Exactly. Intersections will always be the bottle neck. In my opinion, besides minor increases from fiddling with things like lane arrows, it is either splitting traffic up so multiple intersections can handle the load or it's removing intersections altogether.
I played first one just because i wanted to do perfect super insane trafic, but even with mods the game always screwed me with something that was not possible or how it worked like how cars change lanes. But i defienetely made some sick solutions that should work IRWorld.
Actually CS is great for visualising the very point of the video as adding more lanes almost never helped in anything, but I was able to get 89% flow in a 540k city just by being careful with intersections and avoiding traffic lights at (almost) any cost. (Robust mass transit alone got me to only 65%)
Not gonna lie when I saw this video and the name of your channel... this was not what I was expecting. I fully expected a 'serious' one more lane video. I'm pleasantly surprised.
I don't understand how traffic engineers don't understand how the problem isn't capacity with roads, it's throughput. All of the stroads in the US are actually under capacity but have huge bottlenecks. That's what creates congestion. Adding more lanes adds more capacity, which we don't need, and doesn't solve the bottlenecks.
Bad training and bad standards. And a legal system that threatens any engineer who risks doing something less stupid than the standards. My half educated opinion only.
But if an intersection cycles and it has four lanes across, then four times as many cars can cross it during that same cycle as if it had only one lane. So while you might have to stop at intersections, a higher volume of cars would pass through it, the more lanes you had. If they had to line up single file, then it would take four times as long for those same cars to pass through the intersection, and/or only 1/4 of them would make it through during that cycling of the intersection.
@@timogulthat's the point: if intersections are sufficiently far apart, you don't need to build the road between with the same number of lanes as the intersections, it can be reduced.
@@thebigmacd In theory, but the number of intersections tends to depend on the need for cross traffic, not on the efficiency of the feeder roads. You can make very complex arrangements where one road only has three intersections across its length while parallel roads on each side have ten intersections along the same length, so that people loop around to their target destination, and sometimes this is efficient, but you will rarely end up without any benefit to having more travel lanes. There will usually be a point at which travel will back up to the previous intersection, and that is the point at which more lanes were needed years ago.
This one is bookmarked. I've been trying to explain to people that throughput is constrained by intersections for years and now I have an actual qualified traffic engineer saying it on the record. Along with a bunch of other counter-intuitive things such as how reducing lanes can increase throughput by allowing you to remove the signals from a signalised intersection. Perfect!
@@timogul Yes, you wouldn't be able to just remove the signals from an intersection of two major roads where traffic flow and turning rates are high in all directions. But we have to put signals in where a minor side street meets a four lane road, even if there are only 100 turning movements per day, because turning across two lanes into another two causes too many crashes. Reducing that to just one in each direction and removing the signals is an easy win. Of course another option is to block off the minor side street (and most others from the neighbourhood) so that everyone must leave via a single route. That also reduces the number of signalised intersections at the expense of making the start of people's journeys a bit longer/slower.
@@Ladadadada Again though, if the road sees a reasonable amount of traffic, then it is better to have two or more lanes, even if they have to pause at a light every now and then, than to have only one lane. Having only one lane would mean that the whole thing would back up much further. It ONLY works up to a certain amount of "cars per hour," and no further, whereas multi-lane roads can scale up indefinitely, and only become slightly less efficient-per-lane with each lane added. Basically, Lane+1 is more efficient than Lane, but less and less efficient than 2xLane, so long as the number of people using the road is sufficient to keep the bulk of each lane occupied. But yes, like I said, you _can_ just reduce the access points to the primary road. Have the primary road only include a few intersections every mile or so, then parallel to that you have another road that would have intersections every block, so people on the cross streets would feed into that second road, which would move slower on average, then cut across to the faster road to cover the longer distances. It makes shorter trips slower and less convenient, but keeps longer trips faster. This is often how subdivisions work.
@@timogul as they already addressed your points directly I just wanted to add. Even in tines where it wouldn't lead to an increase, it would almost never lead to a decrease in flow as most intersections can only handle a little less than one car lane worth of traffic per hour anyway.
@@cherriberri8373 That's not true at all. I think if that is true of any scenario, it would only apply to a "fair" intersection, one in which all angles are given equal weight. Typically you would not do this. Typically, if you increase lanes above two, you would only do this along one road, not every road that intersects it, and the intersecting roads would only get their turn less than half as often as the main road. In this way, several lanes worth of traffic would sail through that intersection each cycle of the light. You might occasionally also have two such roads intersecting, but this would be the exception to the rule, and would at most back up occasionally.
Structural engineer here. It's strange that traffic engineers take only ONE course on their field of study. I took 14 courses between undergrad and grad school. Since traffic engineers are taking such a broad range of courses, like hydraulics and structural, I can understand why safety factors are so deeply instilled into their work. But unlike structural engineering, traffic engineering deals with a human variable that doesn't seem to be captured in current practice. If I design a wind girt (beam) to support a huge wall of glass, I can make the beam bigger and that doesn't change the wind pressure moving past my building. It does make the structure safer because the beam is much stronger than it needs to be to resist wind pressure. Whatever infrastructure I put in front of the wind doesn't change the behavior of the wind itself. The governing wind pressure, which you design for, is constant. This is not so with street design. The infrastructure you put in front of a car driver changes the way the driver behaves: People drive way faster on wide, straight lanes. If you narrow the lane, it feels less safe to drive on, so people drive slower. From my observations of the built environment, I think it's odd that we don't see narrower lanes in front of schools, which children cross on their walk to class. Instead, we put in wide lanes and 25 mph signs. Speed kills. And speed kills pedestrians. Why wouldn't you account for human psychology that is blatantly observed in your engineering design? It's also odd that we design so reactively. There seems to be a hyper focus on moving as much cars as possible as fast as possible. That's the driving factor for every street, and if it's not achieved the transportation system will just fall apart, and there's just nothing we can do about -- we're always at the mercy of more cars and more cars driving fast. Why can't we design slow streets? And why can't we set a design limit for how many cars a street is going to move ... for forever?
Yeah they narrowed lanes all over the place where I live and now people just drive 2-3 feet over the double yellows and expect everyone else to move out of their way. There’s way more accidents now than before.
I feel humans are now so mentally over stimulated with smart phones that they become painfully bored when things slow down and will become agitated and aggressive even. I feel speed cameras on every corner and physical obstacles like speed humps are the only way force people to slow down.
Thinking about roads in terms of their capacity is more of an American thing, I feel like. It kinda pidgeon holes you into thinking that more capacity = better, and by extension more road = more capacity. It kinda sends the signal that the road's only function is to move as many cars as fast as possible at all times under all circumstances. In reality, there are road users other than cars that have to either cross, or travel those roads, as well as potentially live near them. And in reality, two lanes of traffic doesn't even move that many more cars than one lane. It can even move fewer cars if it's designed wrong.
"the road's only function is to move as many cars as fast as possible" Yes, I've run into a number of times that I've heard that as the thinking. I've challenged them with, "what do you think the best benefit to the city is?" "two lanes of traffic doesn't even move that many more cars than one lane. It can even move fewer cars if it's designed wrong." Yes, that has been shown by those who study traffic. My hometown used to have 4 lanes going through our downtown, and allowed left turns at every side street. It redesigned the road to be 3 lanes with a turn center lane that also restricted the number of left turns that could be made. Traffic flows better, and there have been fewer accidents downtown - which also improves flow.
@@rodshop5897 that sort of setup sounds a lot like my town except that we already have a middle lane with the four travel lanes. I really wish we would just fix the scar through our town, but instead we re paved it recently all while they're trying to make downtown a nicer, slightly more walkable area. I feel like we are trying to appear like a lot of the small towns nearby which ACTUALLY did something to increase walkability, but all the rich NIMBYs with their giant SUVs and trucks demand to see zero actual change
@@cherriberri8373 Yes, for our town, the lane narrowing and limiting of left turn options helped to slow traffic down a bit, while still allowing unimpeded traffic flow. Now there are more parking spaces along the road, which invites more people to stop and shop downtown. It's helped our downtown businesses and lowered the number of traffic injuries.
Car ad: Good enough, is not good enough for you. Because you want more, you hunger for it. Bigger. Faster. Stronger. The all new super max ultra Vroom. (Quickly read disclaimer) *due to being extra wide this vehicle is not legal on all roadways. We are currently bribing politicians to build wider lanes. May be legal by 2026.
11:47 "I could spend the next hour talking about problems with this document" Please do!!! I'd love to hear all about it and I'm sure I'm not alone. For us non-civil engineers, you are our only source for thougtful, intelligent, apolitical, fair-minded, dispassionate discussion on topics like this.
Maybe you could make a video on what the changes you propose would look like for the three intersections you studied before? I think it would be helpful for people to see what it looks like, what it would do to traffic flow (not much change) and how much extra space is created by bringing down the number of lanes between intersections.
I think the point is that the intersection isn't really a problem, but the road width in between the intersections is. It's too many lanes for the "intersection capacity".
@sheepje yes I understand that. I just thought it would be helpful for an international audience to have a visual of what the changed situation would look like in an American context. When I comment on American urbanists with examples from my own city (Utrecht - the Netherlands) I often get the reply that our solutions would never work in the USA. A redrawn map and/or simulation of traffic flow of what actual American intersections might look like when redesigned to be one lane each direction might inspire people to think more out of the box. Reducing the number of lanes would create space for sidewalks, protected bike paths, more green etc.
I am someone non-professional, just interested in this topic, living in The Netherlands. I have the feeling the bigger picture plays always a much bigger role for the traffic design than just the street design itself. As a cyclist I don’t even care if the tarmac is red. The thing is, the entire traffic situation could perhaps be improved with replacing 3 signalized intersections, with just 1 signalised intersections and two detours to reach the other intersections, which then don’t need signals anymore. That one intersection can then be upgraded to a turbo-roundabout with non-level crossings for cyclist/pedestrians, or non-level intersections with exits/entrance towards a roundabout. The entire section between the three junctions could then have service streets next to the main road. These servicing streets convert the stroad into a road. The main road is then one lane in each direction. The service streets will be lower speed, suitable for cycling, and suitable for servicing the exits of neighbourhoods, companies, stores etc. Additionally, they could be even made one-way traffic. This high-level planning is often not covered in the urban planning video’s. But from my youth I always remember the safe cycling routes not to be ‘red tarmac cycle streets’, but ugly converted streets to low volume traffic, with a lot of exits and street parking. This low-cost conversion with a high-level plan, in my opinion this is where it all started in The Netherlands. This involves neighbourhood plans with one-way (two-way for cyclists), cutting streets and thereby convert 4-way junctions in T-junctions. Moving cycling crossings away from the main road intersections, if main roads are one-way lanes, with a middle buffer area, this makes it ideal and easy to cross for a cyclist or pedestrians often without signals at all. This high-level design is much more important then all the nifty design details of expensive street-scapes. The aim is to have a better overall traffic flow, with sufficient access to each area. Would be VERY interesting to see some before/after neighbourhood design in The Netherlands in the 80s/90s, as well as some proposals to actual field cases in the US, for instance these junctions in the video. Nice video btw! ;)
The "there's something for everyone to like in reducing lane count" is really interesting, theoretically. I worked as a civil engineer in the US for a bit (and don't anymore because it sucks), and the DOT I worked for wanted very badly to reduce lane counts - calling them "road diets". They often did trials of this via temporary traffic control, and while traffic throughput never really changed, public opinion was constantly massively against them. Sometimes they actually did the lane reduction when the road was rebuilt, often not. Drivers in the US constantly vote against themselves here.
Because many US drivers feel like they have the right to speed, and how are they going to dangerously swerve around you if there isn't a second lane? In reality the benefits of speeding are near nothing, and only makes the road more dangerous. Anyone who's ever timed how long it takes them to drive from point A to point B on a regular basis will quickly realize that speeding saved them a minute or two at best. You know what really adds to your travel time? Being stopped at poorly designed intersections.
Idk what it is about Americans voting against their own interests constantly, not that it’s exclusive to the US but still. My town actually voted down a proposal for a solar farm because it would “ruin the landscape”
They vote against them for good reason. If you only have a single lane, you are beholden to the driver in front of you. If said driver wants to drive 18 MPH under the speed limit, you do too, whether you like it or not. Having a second lane means easily getting around the idiots.
Or if Grandma decides to do 32 in the 40. I went on a trip to Hawaii recently, and the island I was on had one major road going, one lane each way. Someone ahead of me decided they didn't want to do the 50 MPH speed limit, and decided to do a leisurely 40 MPH for about five miles. By the time he turned off, there were easily 200-300 cars behind us (probably more, we couldn't see the end of the line). And in front of us there was nothing but open road. This one guy managed to waste 7.5 hours of the rest of humanity's time, and the only reason it happened was because there wasn't a way to pass him.
And less water absorption of the ground, so with heavy rain there's a higher risk of flooding! Awesome! In my city (Utrecht, NL) a road near me was actually redesigned a few years ago. Two lane road, one lane each direction. The two lanes were made a bit thinner, to slow cars down a bit as they would often speed. The space that came free in the median became basically a ditch, so any water that fell on the road would go into the ditch and back into nature. It's super green, there's all kinds of low plants and flowers growing. And it's nice to know the municipality is future-proofing the city, as with climate change there simply might be more heavy rain after periods of dryness.
I feel like this single lane thing will be severely hindered in North America because people think they have a right to speed past others who they perceive to have what they consider nothing important to get to. Most car drivers believe theres multiple lanes because the right most lane is the idiot bad driver/semi truck lane, the middle lane is the speeding lane, and the right most lane is the super speeding lane.
Nobody wants to be beholden to an idiot going slower than they should be. If you were stuck on a sidewalk behind a wheelchair going 1/3rd your speed, you'd want to get around him too.
This really reminds me about “the goal” or “the phoenix project” where one of the key takeaways was that it is useless to expand the capacity of the system anywhere except at the constraint, since everything would just pile up at the constraint. You’d think that it is obvious, yet this issue has been popping up all across a variety of engineering disciplines. Crazy to think about
So essentially, it generally makes more sense to think about urban street geometry from a qualitative perspective rather than obsessing about quantitative throughput. Awesome, real perspective shifter. I think we intuitively understand this when we advocate for wider sidewalks even when not strictly "necessary" for moving people around. We have to think of streets as places to be and not just serving conveyance needs. Subscribed, nice video
I can’t this hasn’t really been covered before- and it absolutely makes sense. Thanks for making this video. Seeing arterial road “realignment” projects widening city roads to 2-3 lane arterials is even painful to see knowing that it’s essentially a pointless waste of money and wasted chance to properly redo the road. If you have any resources to share that could help us spark these conversations it would be really great.
In Copenhagen (Denmark)is it normal to so many bikes because the road is designed for it. There is it normal in rush hour to the lanes so filled that maybe 200 bicycles cross every time. But Denmark and Netherlands are also the bicycle capitals of the world.
That doesn’t sound at all extraordinary. Lots of one-way bike lanes can safely fit 2 bikes side-by-side, and where I used to live there were some bike lanes in the downtown (and through or near the university) that could realistically manage 3 or even 4 abreast, with safe passing space. Even with single-file, 1 second is plenty of follow distance on a bike if you’re an experienced rider, and even if you’re not very experienced but also not going that fast. It wouldn’t be difficult to get 2 bikes/second on a busy single-lane bike lane/path (which would translate to 4 bikes per second if it’s a two-way bike lane/path or two opposite-direction one-way paths/lanes).
@@natbarmoreYeah, in theory… It doesn't occur in reality, startin with "safe distance" from the bike before you (min 1s), which basically at least halves the "realistic maximum"…
Oh boy, do I ever hope SOMEONE in Brighton & Hove City Council's Highways Dept watches your output. Our old city, which lies on the South Coast of the UK at the confluence of two valleys, was built for a dirty weekend a couple of centuries ago and definitely WASN'T built with current traffic levels in mind!! Great buses, pretty good rail links, evolving cycle lanes, rubbish road junctions (no design consistency), inappropriate use of mini-roundabouts (Got Google Earth? This one is a classic 50°49'53"N 0°10'20"W). Mercifully, our bypass was completed before our economy died of boinkered stupidity.
A mini roundabout would be there as a way of traffic calming an area. But I see that the surrounding streets don't have mini roundabouts until you get up to Cromwell road.
If you think the roundabout on Goldstone Villas is bonkers, try this one: 50° 51’ 31” N, 0° 5’ 41” W No idea what could be the purpose of it, considering it was always such a minor crossroads, and currently half of it is blocked by parking spaces!
I visited Brighton this summer and was really surprised just how many cars were squeezed in, so many streets that have gone to such effort to keep two travel lanes in. I think I've never had so many near-misses 😅
Anyone who drives a lot knows going down the side streets is faster than taking the main stroad through town. The side streets have only one lane in each direction, less traffic, and no shopping centers. Even if the posted speed limit is lower, it flows better and is faster than the stroad which has lots of stopping and tons of traffic. Taking back roads to get somewhere faster only works if those roads exist and in a lot of cases there are no back roads. Instead of more lanes what we really need is more roads.
This fills in a blank for me for why Seattle has imposed "road diets" on several arterials. One such arterial went right past our old place, and I have to admit I was skeptical of turning a four-lane arterial into a two-lane+dual left turn lane. But SDOT argued that the data supported it - they couched it primarily in overall travel times not increasing, and explained the fairly obvious and logical safety benefits of fewer lanes for pedestrians to cross, or for speeders - like myself, if I'm being honest - to dart back and forth between while passing each other. And I've gotta say, this change 100% delivered its benefits as advertised. Much more pleasant street to walk along, cross, live near, and drive on - and genuinely, no increase in travel times. BUT - my big unanswered question until this moment was *why* travel times would not increase, since it seemed to me that this figure would necessarily be a function of road capacity and demand. And this video just filled in that blank for me so - sincerely, I thank you for it!
Love this, and you've given me words to explain a vague intuition. One rebuttal that could be included (if only time permitted) is the fact, unappreciated by one average 70-something American whom I otherwise respect very much, that lane capacity does not vary greatly with speed. The separation between vehicles at 80mph is twice the separation at 40mph, with the result that the vehicle count passing a point in an interval of time remains the same. This paradox, and overlooking the reality that driving 65 vs 55 affects total travel time negligibly, leads voters into asinine political incentives. So much waste and so much unpleasantness. There's also a fundung problem: state and federal funds are spent aggressively on high-speed roads, leaving very little for rural or urban circulation.
Your comment about increasing speed not increasing capacity is indeed very counter intuitive, but if you assume people drive with safe separations then it's true. Thinking about it a bit more, it occurs to me that if you take a given mile of road and double the number of cars on it then you halve the separation which means you halve the speed. This means that although twice as many people are trying to drive along the road the half speed means there are still the same number of cars pet hour as there were before!
Braking distance goes up with the square of the speed, so separation should actually be four times bigger at 80 mph than at 40 mph. Most people aren’t keeping that much distance though.
@monobryn64 true, and especially for larger vehicles following small vehicles! (Or small vehicles cutting in front of larger.) But if all vehicles are approximately the same, the governing process is reaction time: brake lights to eye through brain to foot.
Honestly, I would expect that the average practicing American engineer falls into this speed fallacy assumption... unless there's a specific table in a manual somewhere telling them in big, bold letters that it's NOT TRUE.
Great video. One criticism: Capacity under non-ideal conditions is important to consider. In Calgary, Canada, roads freeze and thaw like 40x a year, leading to a lot of road maintenance. Temporarily losing a lane on a one or two lane road means a lot. A road needs at least 3 lanes in total before its even feasible to work on one without losing the road.
Just use temporary traffic lights. How do you think they do maintenance on 1 lane roads? Yeah it's way less efficient but during road works of course it will be worse
Ok, but how often does having a short stretch of an urban or suburban road under construction cut off access except to destinations in the construction zone? How often in an urban or suburban area is there _not_ another road people could take to get where they’re going? Sure, the alternate route might be longer, and it might temporarily put too much traffic on a side street. But for basically any urban/suburban street, you’re occasionally going to need to do repairs to the whole width of the street, so even with more lanes you’re _still_ going to have to figure out how to deal with that. Whatever strategies you have for dealing with having 3 lanes of a 4-lane road closed/blocked/torn up will work even better when 1 lane of a 2-lane road is closed/blocked/torn up. (Added bonus: in many cases, repairing both lanes of a 2-lane road at the same time would take about the same time as doing one lane, so you could significantly cut the amount of time the road was under construction if you could just close or all-but-close the entire road.)
@@skylarius3757 But it would flow more efficiently, especially when outside of peak capacity. No more waiting at a red light when there's nobody actually going on the other lights that are green. Roundabouts ftw.
Roundabouts are great, up to a point. When there is too much traffic you'll reach a point where a (well designed) signaled intersection has a higher thankfully throughput. But you need smart signalling and the correct direction lanes, you my even need to sync signalling across multiple intersections. There's a road near where I live (in the Netherlands) where the traffic lights of 7 intersections in row all communicate with each other to optimize the timing of the lights for the best throughout. During peak times traffic is still doable there, which it wouldn't be with roundabouts.
finally, an urbanist who does not repeat the same old points. I really like what you said about the NACTO transit street design guide. I always had a feeling that there was something wrong and your explanation confirmed it
Great video! I hope more people find your channel. I would like it if potentially you could make the video longer and dive more into the details at the end, but that's up you of course. In any case great video!
thanks! unfortunately i got stuck on this video for around 6 months due to life happening, but im hoping i can make shorter, more frequent and higher quality videos soon. Thanks for watching!
I like your point about the capacity in the NACTO doc. I think the figures are helpful in arguing that bike lanes and bus lanes have greater capacity and therefore if we expect the population to grow then we can accommodate more people in a fixed amount of space without needing to tear down buildings to widen streets. And just to be clear- the Dutch don’t have any rules like “we can take a lane out on this street because the peak hour traffic is below a certain threshold”? In a lot of US cities it is common to say if a street has below a certain volume we can take out a lane because the demand can be satisfied by a single lane without creating traffic. But I guess there is no parallel equivalent in the Netherlands?
As a trucker in the US, someone I'm willing to bet you've never even considered, these narrow 2 lane roads make life more expensive. Truckers need the extra space to escape brake-checkers, make sharp turns, and get around hazards such as parked/pulled-over vehicles, delivery vans, road debris, or even pedestrians. The way Europe deals with these issues is by having truckers live in cramped bunks squeezed between their seat and trailer (US truck cabs are about 400% larger than European caps on the interior, allowing us to live VERY comfortably in the truck for weeks or months at a time). This means European truckers demand higher pay, either to deal with the discomfort or to pay for expensive hotels every night. If they demand higher pay, then the cost of transportation rises, so stores and vendors raise the price of goods to maintain the same profit margin. This is the primary reason it costs nearly 3 times as much to live in dense cities in the US (like New York or Los Angeles) than it does to live in rural and suburban communities with larger roads. Urbanists never think about truckers when they advocate for removing highways and narrowing arterial roads. As for traffic flow, EVERY primary road must have AT MINIMUM 4 lanes so that people going HALF the limit don't grind the city to a halt; something I've witnessed myself multiple times as a trucker.
This is wonderful. But there's a big problem. Unless you're one of the 3.5k people that watched this video, you won't understand this. And here's why that's a problem. I actually know an intersection exactly like this that I travel through near Arlington, Virginia. The road is one lane each direction but widens to two lanes each direction for an intersection and narrows back down to one lane. Nobody uses that extra lane, because if you do, (and I do), you'll get honked at, cursed at, and blocked for being that jerk that tried to pass everyone at the traffic light. It's the same problem with zipper merges. I was driving with a friend one day and I used the extra lane, and he said, "wow, you're one of those people." I proceed to explain the exact same thing you just explained. Their response? "yeah, but still that's so rude, just wait." The problem is not that people don't understand, it's that people refuse to understand.
Haha, I got honked at today for the same thing. And this was a person that was behind me as if I was wrong for not getting behind them as the road narrowed to one lane. So bizarre...
I'm confused as how the intersection works. The way is should work, is that one lane widens to two or three lanes (left-straight or left-straight-right) and there is only one exit lane in each direction. Does your intersection have go from one to two, intersection to two exit lanes for the direction and then merges back to one after that? If so, it's not that the concept introduced in this video is flawed in anyway, it just mean that the traffic design of your local intersection is shit. Which is not at all surprising.
@@tommihaapanen846 In the netherlands a lot of 1 lane urban roads widen into four lanes at the intersection: one left, two straight ahead and one to the right. The two straight lanes than merge into one, exactly as shown in the video at 2:14 This works very well as it leaves space for the cars to wait and accumulate. Then then spread out again on the single lane. So no, that intersection is designed correctly and people are reducing the efficiency of the intersection by only using one que-lane
Louis, which intersection are you referring to? As an aside, my "holy grail" for road diets in Arlington is Glebe Rd. from 395 to Ballston. I hate driving that stretch because if you take the left lane, you'll get stuck behind a left-turner and if you take the right lane, you'll get stuck behind a bus, trash truck, etc. I have maintained for years that the 2x2 lane configuration is functionally obsolete and should be completely eradicated within the Beltway, if not further.
Very important point to also get car drivers on board with the idea of reducing the number of lanes: it will make car journeys faster and more fluid! Because you will be able to remove traffic lights, you will be able to make turns. Too many lanes causes every intersection to have a traffic light.
Are roads in the Netherlands currently designed with fluid traffic in mind? In Belgium they seem to do everything they can to slow down traffic. Speed bumps, chicanes, 30 km/h zones, zones where you can't overtake a bicycle (makes sense - what's safer: a car in front or behind you when riding your bike?). Potholes are getting bigger by the day, but speed cameras are state of the art. What used to be a 30 min journey is now 40 min if you're lucky.
Probably because design is not a word in the Belgian language /s So on the one hand, Belgium is pro-active in trying to reduce traffic incidents, which is good (and something which is still up to debate in North America for example), but on the other hand there isn't yet a mindset to implement safety from the ground up in the design of our roads because Belgian urban planning is shite. So what we end up with is a battle against symptoms (traffic fatalities) with band-aid solutions (speed bumps), but no desire yet to fix sprawl or start to *formally* classify roads as roads, streets, etc.
Huge issue with one lane roads that is if there is any problem the traffic completely stops, multiple lanes allows for traffic to continue moving in the same direction. Real life is a thing, and while single lanes sound good in a bubble they don't stand up in cities that often have many different events all occurring at the same time.
@@therealdutchidiot How do they prove me wrong? How do you get by a stalled vehicle? How do emergency vehicles pass in a single lane divided road? What happens if fire needs to work on a roadside burn? Is the road closed completely? What about construction? What if there is a large event taking place on the street or road? I assure you these issues exist despite your denial.
@@Zanduras1 How do Dutch roads prove you wrong? Because within cities roads are never more than one lane per direction an the issues you're describing simply never happen. Ever.
There is also one other factor separate from traffic engineering that contributes to throughput and flow - driver (and pedestrian) IQ. Obviously this is subjective but the drivers here in Toronto are not only moronic but borderline malicious.
I was so scared when a channel called "build the lanes" popped up in my feed. But I'm glad you're not someone who just wants more lanes because car propaganda xD
It's logical, really. All (exceptions?) systems are limited by the bottlenecks, not what goes between them. For some of them, like bikes and pedestrians, actually reaching "full" capacity requires a concentrated effort by the people to go out there, unless we're talking very popular routes that can reach those numbers naturally.
Multiple reasons why you may want more than 1 lane: A. Someone pulls over to let someone out of the car. B. Someone wants to turn across traffic into a side street. C. Someone is doing 20 under the speed limit. Emphasising good alternatives to driving and in particular, protected bike lanes is good but being disingenuous and saying that there's NO good reason for a road to be more than two lanes wide is just agenda pushing.
driving in most british towns is not really like this-narrower roads and more curves than USA-but it's true, the town centers get fully saturated and at a standstill. The key metric has to be how easy it is to get people out of the busy patch / off the road wherever they are going.
THANK YOU! I live in LA and I spend more time waiting at intersections than I do "in traffic". I am convinced traffic in LA (at least non-freeway driving) is bad because of the incessant insistence for almost EVERY intersection to be controlled by traffic lights "for safety".
I've been a pedestrian, transit rider, cyclist, and driver in LA, and I can say for sure that ALL of them sucked when it came to waiting at intersections/traffic jams. Riding a bike on the streets was dangerous, buses stopped every other block, walking felt like stepping in an oven on a hot day, and driving was stop and go all day.
Nice video! I always appreciate your insights. The video I loved the most was the lecture you gave at CSU Sacramento. For this format, your sound design could be improved. If you are interested in improving your audio, it can be done cheaply. Look into getting a good mic (you really don't need anything more expensive than a wired SM58), an audio interface (like a Behringer UM2), a 1 meter XLR cable, a mic stand (mine just clips to my desk), and a pair of studio headphones (I've had luck with Sennheiser). You can get a lot of this stuff used. Record with Audacity software and watch a couple tutorials on using the software tools to improve vocal quality. Also Google "microphone technique" and read a couple tips about that.
Love the video! There’s a stroad in my town that goes right by the local high school, 5 lanes of traffic (two in each direction and one turn lane) and a massive car dealership on the opposite side of the street. TECHNICALLY there is supposed to be a school zone of 30 mph for driving during the week and the normal speed limit is 40 mph, but the road capacity easily can handle 50 mph. Next to a school! This one road is also the main arterial that runs through town, so the road is constantly facing through traffic that could easily shift to the highway just half a mile westward. I’d like to see the road cut down completely-one lane in either direction, separated bus lane for students and for people going northwards to downtown, and a bike path for bikers to school and work. Will traffic be slower? Maybe, but that’s the point-it’s a school zone!
A positive side effect of changing to single lanes will also be that North Americans would learn and finally get used to merging properly without collective road rage outbreaks 😂
The concept of 'traffic flow' is lost to many people. Car drivers will want to emulate a laminar flow, but instead it's like water droplets trying to overtake and crash over one another. The latter is the definition of a turbulent flow. Psychology plays a major factor in traffic. To a severely underestimated degree.
I moved from a big city in the Northeast to suburbs in the PNW and I immediately saw the problem with road design. stroads and arterials dominate. There is no way to turn left without a separate cycle of protected left turns. There are no alternative roads and detours you can take that you can get with grid pattern and multiple parallel roadways like in many cities that can help spread out traffic. This piles on top of lack of transit, non motorized options and zoning systems that help make traffic worse.
I haven’t been this excited watching a new video from a new channel (at least to me) in a while. You are approaching the problem from a perspective which makes sense to me - queueing theory, which I think too few people are familiar with, I’m no expert but I have passing knowledge of it, as such I sometimes wonder while walking around town how would one model traffic - what’s the throughput, arrival rate, processing time, where are the bottlenecks, etc. I’m no traffic engineer, so it remains a curiosity, but I would love to explore those questions, the revelation between the steady flow of a country road and stop and go of a city caused by intersections (though in hindsight should have been obvious) feels like it opened a third eye for me, I don’t think I will look at roads the same way.
Even if the theoretical throughput of a lane of traffic is 1,800 vehicles/hour, I feel like it's important to bring up that the theoretical throughput of a lane of intersection is going to be significantly lower than that. At best, any given lane is going to average 40% of 'green light time' while at an intersection, which brings theoretical throughput down by 60%- though in practice it would be significantly lower than that as you have to accelerate from a stop which is going to cut into the number of vehicles you can get through each green line at an intersection.
You strike an incredible point on the realistic balance between 'Orange-pill' urbanism and car-first infrastructure. I particularly like your point about the size of sidewalks not increasing the capacity, but improving the quality of a system for everyone involved. As a traffic engineer, do you have any insight into how best individuals can influence their cities to build smarter infrastructure like you explain here? Also, a more technical question on your laminar flow approximation of traffic. I'm a MechE student myself, but I've often thought about traffic engineering. Do you think a theory that roadways with more turbulence are more dangerous has merit? In that I mean is there some combination of factors of vehicle density, speed, and length in which something akin to a "Reynold's" number can be calculated for a roadway, and then with that an estimated area where traffic would become viscous, and therefore more dangerous? The only thing holding back this theory is how you could assign a viscosity to traffic flow.
Great video! I've been trying to say this to others on urbanist communities who generally solely seem to only circle jerk the "muh induced demand" phrase ad nauseam without providing much discussion on road design itself. Good road layouts / designs / geometry doesn't only benefit pedestrians and bicyclists, but it is also for the benefit of the driver. Most urbanist communities fail to provide this crucial messaging that the opposition would have a harder time arguing against. Talking on a tangent - for things like controlled access highways in urban and suburban areas, a lot of lanes just lead to levels of complexity that humans cannot handle leading to crashes... leading to traffic jams.
Finally there is someone stating facts about the NACTO scale. As a civil engineer I hate the way that urbanists think that reducing lanes everywhere and building different infrastructure automatically increases use of bike paths or public transit. As long as the comfort, safety and especially speed of the mode of transport allows it, people will take that set mode of transport. Are bikes faster? Bikes are the answer. Is the car faster? Cars are the answer. You can't make a society but you can always facilitate everyone.
Actually, that's exactly what will happen. Most people choose the most convenient way of getting somewhere. Within cities there's absolutely no need to make the most convenient mode the car, though there should still be capacity for it.
Ignoring choke points, why they are choke points and just increasing more flow towards it obviously just creates more problems. Imagine if you engineered anything else so mindlessly.
As an avid driver and car lover, I would LOVE for more public transit and better alternatives to driving. Cause people who don't like to drive tend to suck at it. Giving them an alternative would get them off the road and out of my way. My road rage goes away, and everyone is happy. Yay.
The double-edged sword with road hierarchy is that everyone is forced to use the same roads while the other, surface roads have very little traffic. The best way to do it is to have options. At least one lane for every direction of travel on a road, and multiple routes you can take to get to your destination. Grided cities worked a lot better in American cities than they do now with a single arterial road everyone now has to use.
This ignores that stroads are typically not simply routes for through traffic, they are also dealing with cars entering and exiting large numbers of destinations along the stroad. Cars pulling into and out of these parking lots and driveways by necessity are going at speeds much lower than what would be desired for steady state flow, and their sudden entry onto roads (often from poorly designed interfaces with poor visibility) poses risks to traffic passing through. Ideally you would have a proper road (which would have minimal intersections btw) for high speed, long range transit which would feed into dedicated slow speed, low capacity streets that service the various destinations. Stroads, pretty much by definition, are a compromise between these two attempting to do both. Additional lanes aren't there for maximizing capacity, they are there to allow cars to move at wildly different speeds simultaneously. If you take a two lane road, add on two right lanes for slow merging traffic and a shared central lane for left turns, now you're up to a 5 lane stroad with no additional capacity. Now stroads are a bad compromise that create lots of problems - greatly varying traffic speed is dangerous for motorists, extremely wide roads are terrible for walkability and pedestrian safety, the lack of a proper road creates congestion, large numbers of innefficient intersections are unavoidable, and they are expensive to build and maintain - but the design of stroads must be evaluated in the context that demands the stroads. If you eliminate those 3 extra lanes that aren't providing any capacity, essentially turning the stroad into a road, it is no longer able to accomplish the street functions that are necessary due to the absence of proper street infrastructure. Eliminating the need for stroads is a much harder challenge, but it is critical to see the desired improvements to quality of life.
5:11 For non-engineers and non-Americans, it really IS true that the U.S. university system only leaves room for civil engineering students to take about 1-4 classes in their actual career field after all of the mathematics, general science, computer, elective, and cross-disciplinary "breadth" course requirements are satisfied.
Interesting, that reminds me of my husband's experience in law school which taught him to pass the bar, but didn't teach him much in his specialization. It is expected that attorneys will be training on the job for about the first 3 years.
I have just checked up on Danish calculations. The free flow capacity on a 1 lane road is estimated at 1800 vehicles per hour. On 2 lane roads it is 2200 vehicles. A 2,5 meter wide bicycle lane has a capacity of 3000 bicycles an hour. With cross sections and traffic lights these numbers reduce significantly. I suppose this is why roundabouts are popular among road planners. It is in most cases much more effective than a traffic light. Bicycles can easily blend in bicycle lanes, while cars have more problems. Still, roundabouts are generally much more effective. As shown, additional lanes do not help much when you have cross traffic. I suppose more than two lanes in towns are in most cases contra productive, especially with undisciplined drivers like in the USA. My own anecdote experience is that in Germany on highways (Autobahn) drivers keep to the right and faster cars can pass on the left. But in towns with 50, 60 or 70 kph restrictions hardly anybody keeps to the left when there are two lanes. They pick a lane from the start and stays there when they are going to position them selves 2 to 3 km later. Even though it is taught in driving lessons, blending like a zipper is not followed by many in Germany in towns and cities. So people fear being caught in the wrong lane. This is possibly the main reason why 2 lanes has almost insignificant higher capacity than 1 lane in each direction.
I love how your first example show that a dual carriageway two lane road would more than suffice to swallow all of the traffic even for the most busy intersection. All those extra lanes? Rolling parking space.
Another great case study where a lot comes together is the veldmaarschalk montgomerylaan in Eindhoven, 2x2 highway converted to a 1x1 road with a 1x1 bus corridor which also functions as an expressway for emergency services into the centre, intellegently coupled signalling systems, and a multilevel crossing with the inner ring road.
This is literally why I never will move to a different country than the Netherlands. Growing up here you take it for granted but once I visited other countries, every time I was stunned by either how unsafe/dangerous it was or how impossible it was to get around without (or even with) a car.
I live in Kansas City and they've cut some urban residential streets from four lanes to two recently, making room for street parking and bike lanes. They've done this is a few more midwestern cities as well, along with adding double diamond interchanges and roundabouts. There's a bike lane outside my apartment now, and in five years here, I think I've seen two people use it. Still, cutting down the lanes makes sense given the throughput element and its relationship to intersections. I like having lots of lanes - KC has more freeway per capita than any other city on earth, and I love getting around here - but it's a luxury in most cases. This is a lot better than what I usually see from MMT channels and I'm subscribing.
Yes yes yes. The bane of my life though is calculating stopline capacities in cities - mixing the theoretical and the observed. As a fellow transport planner (and traffic modeller) - I salute you!
As I understand it roundabouts aren't made for throughput (it's usually not mentioned as benefit of roundabouts) but for safety as well as better traffic flow. Cars don't need to wait longer than necessary, as soon as there's a gap they can enter the roundabout. Though this relies on a gap existing, so intersections are better for heavy traffic because the traffic lights guarantee an upper limit to the waiting time. If I had to guess I'd say the throughput isn't really much better but the minimized waiting times can still accelerate traffic on average.
I don't have a scientific explanation, but I think it really depends on the amount of traffic as well as the size of the roundabout. If there's too much traffic, you might have to wait at a roundabout for a long time. Maybe shorter than with traffic lights, but because it's not controlled it can feel longer. In the Netherlands cyclists and pedestrians often have right of way on roundabouts. As a driver you're waiting both for cars and cyclists on the roundabout when you want to enter, and again wait for cyclists when you want to leave. If there are a lot of cyclists using the roundabout continuously, it can create traffic jams. In my experience here in NL, roundabouts with significant amounts of traffic are often placed near intersections controlled by lights, so traffic from different directions basically come in waves rather than continuously. Of course having to wait at a roundabout for a long time can increase risk of accidents, as drivers might decide to quickly jump in front of other traffic. In NL traffic lights for cyclists nowadays often have a button that lights up saying "please wait" or something like that when you arrive. Pushing the button or riding over magnetic strips on the road activate it. Often it doesn't change anything to the operation of the intersection, but psychologically it makes cyclists wait for green more often, as they know they'll get green sometime soon anyway.
Roundabouts are great for roads with one lane per direction and even flow in all directions. It also makes turning left very easy. Two or three lane Roundabouts don't work so well. Also if the traffic is very high from two approaches. Vehicles coming from the other directions will have issues entering the roundabout.
Look on TH-cam where there are good simulations of just this with throughput numbers. Roundabouts are split into simple one lane, double lane, dual roundabouts, etc. up to the "magic" roundabout. They are in general more efficient for local traffic than lights, but less efficient than say a diamond interchange. The flow goes something like stack interchange/double crossover diverging interchange > diamond interchange > double roundabout > single point interchange > simple roundabout > drivers waiting/figuring it out on their own > simple lights The exact ordering can vary by simulation, as some don't include pedestrian or bike areas, and can also be affected by local terrain and the presence/absence of public transport and truck traffic.
The nearest big city is doing road diets, permeant protected bike lanes as well as a light rail. It was argued by Warren Buffett that they should improve the bus lines first because currently they aren't just bad... They are literally unusable for everyone though some poor souls have no choice. My question is when it comes to down sizing roads or putting in a light rail should they not also work on the buses? I agree with Buffett that I think the bike lanes and light rail would get more use if they improved them first. But Wanted to know your opinion as well (if the city is important it's Omaha.) Also, I'm a driver that wants less fools off the road and am more than happy to patiently drive around public transit if that means they are! Besides sometimes I do not want to drive.
I live in Bristol, in the United Kingdom, and I never noticed it before watching this video, but we actually have a lot of roads that are single-lane that widen to two or three lanes at an intersection, and double-lane roads that widen to 4-5 lanes at the intersection. One problem I've noticed a lot while driving is that our single-lane roads (of which there are many, because our infrastructure has to fit in cities that were built long before cars existed and in some cases follow a street plan that was decided in the middle ages) cause, is that it makes it extremely difficult to keep traffic flowing in cases where a vehicle needs to stop, such as to turn off into a side-road, or get around a bus that has to stop to offload passengers, or even just a vehicle that breaks down. Having a second lane allows overtaking in these instances, but is very much a luxury.
Solid video all around. I know in my city, we have way too many traffic signals, simply because the streets approaching the intersection are multilane, and going to one lane in each direction would immediately disqualify the need for a signal at all. Also glad you brought up the theoretical capacities of bike lanes/sidewalks/etc, it always felt weird using Streetmix for example and seeing these wild capacities if everyone gave up their personal space and comfort. Like yeah a bike lane can move more people on a congested street than a car lane, but I’m trying to make a safe dedicated lane here, not too concerned with this full saturation throughput lol.
Been saying this for years. Flow is more important than capacity. Especially when my city council was hell bent on building 6 lane monstrosities that stretched only 600m to the next intersection and then narrowed back down.
Heavens above! Finally something I had been thinking about for a while. I read that Denmark or Sweden found two lane roads were best and safest. Now I can visualise that. Our Government is building RoNS - Roads of National Significance and RoRS - Roads of Regional Significance. They will be two or three lanes in each direction. This is going to cost Billions more than two lane roads (one in each direction), and it makes it more dangerous as our appalling drivers see this as a contest to use the road to get ahead of other traffic. Our road toll (deaths from traffic crashes) per capital is one the highest in the developed world. This is not a Banana Republic! It’s NEW ZEALAND!
Your high road toll is probably more to do with over-policing speed with cameras everywhere. Like in Australia you'd be better to stop doing this and focus on the over 65 category that is the most dangerous by far.
10:19 i thought it was obvious when ive seen this graphic that its talking about maximum theoretical throughput, obviously you wont actually get those numbers except under extreme circumstances. I think its still useful when people talk about how cars are "efficient" when they are so clearly not when compared to other modes.
So I like the video, nice to see actual stats to back up claims. But here in Toronto we have added bike lanes to almost every street, and traffic has gotten to a choke level, where the transit can't even complete their routes because buses can't get to the terminal.
sooo.... What do you think of videos from Vietnam where everyone just slowly proceeds into a completely uncontrolled intersection and goes wherever it is that they are going? Eyeballing it, the throughput looks nuts. Also. My city has a number of intersections in close proximity where you have one entering and one exiting the intersection from each of the four directions and a large amount of pedestrian traffic. Currently it's a two phase light (N-S green and W-E red and then switch) with ped signals. What do you think of having one green going around clockwise (or cc, whatever) with the rest red with ped scrambles to facilitate pedestrian movements.
Hello from Sacramento! I recognized so many of those stroads, especially Howe Ave. I have the misfortune of needing to drive on Howe once or twice a week. Sacramento seems especially bad about this, so so many stroads! I will say this...I'm a mechanical engineer, not a traffic engineer, but I've heard the "capacity" or "volume" argument so many times that it was really mind blowing finding out that it doesn't really matter, even for bike lanes (which makes sense if you think about it even for a moment). I remember looking at an "active transportation plan" for the Pocket/Greenhaven area where the sections of Florin and Meadowview leading to I5 were shown as not eligible for bike/pedestrian infrastructure because, at 40,000 cars/hour, the traffic volumes were "too high!" (Another example of "we don't ever dare take space away from cars!"). I remember thinking how absurd that was on so many levels. And this adds a new level to the absurdity. In any case, I'm looking to get out of here. I don't think California in general, or Sacramento in particular, will ever get it. There is just too many entrenched interests and too much money sloshing around in the political system to ever expect anything to change. Franklin Blvd. was supposed to get the "Complete Streets" treatment four years ago. They keep saying it's going to happen soon and then...nothing. Don't even get me started on how pathetic SacRT is these days. I'm looking at Delft as my final destination, if I don't get run over first.
@@barryrobbins7694 Nederland changed because a solid plurality, if not a majority, of the public rose up and said no. And very aggressively at that. When you have a system where 85% of all trips are by car and most people don’t really know of, or can’t visualize an alternative, then you have a vast majority who are either indifferent or hostile to change. That is the situation in America today. The Dutch stopped before really even getting started. We have literal decades of entrenchment to reverse. And it’ll probably take twice as long to reverse the damage as it took to cause it. Simply “getting involved” won’t fix that. Today’s “advocates” are too feckless and would rather beg for bread crumbs and incrementalism than demand real change. I’m pushing 50. The day when it’s no longer possible, or safe, for me to keep driving is coming, and probably sooner than I think. I don’t see America looking remotely like Nederland 20 years, or even 30 years from now. I don’t intend to be trapped in my house, experiencing cognitive decline, because I’m too old to drive and every other mode is unreliable or too dangerous. No thank you. Better to leave now while I can and move somewhere that I know is already safe and reliable for the elderly than bet on a future that is unlikely to happen in my lifetime.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. The United States is a dying empire. While China has evolved, the United States has devolved.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. The United States is a dying empire. While China has evolved, the United States has devolved.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. China has evolved, the United States has devolved.
Great video! I never thought about that. Now I feel bad for using that source in my own video. Good reminder that we aren’t the experts. Still hate the Coomera Connector project tho
Really great video, this is something that's frustrated me alot about UK road design. So many of our roads (specifically the carriageways) are bigger than they need to be 'just because'. There's one near me that almost looks as though it should be 2 lanes in either direction but is one (despite bottlenecks on either side 500 meters apart) so you end up with rediculous weaving and awkward queueing. It's like the planners wanted to "suggest" driving side by side but without drawing a dotted line to make people do it. It was recently resurfaced and every time I walk on the bumpy uneven pavement I think 'that's so much asphalt for no added benefit' Trying to do Street improvement projects here runs up against the inevitable assumption that roadspace = congestion capacity, so as much as people are statistically on board, they still resent any space being taken from cars, even the useless space no one is able to use
This video is a great example of why simpler transportation systems seem to work better, and layering adjacent but not conflicting transportation modes seems to be better than doubling down on one. A boulevard with a light rail line, bike lanes, and sidewalks moves many, many more people than the same space with just cars and sidewalks.
Living in a city that has installed traffic lights in roundabouts, THANK YOU! It is nice to know that there are non-insane traffic professionals out there.
When my son was at Uni members of his course were given a task to 'prove' that traffic lights were better for flow than other systems. The research was of course paid for by a company that made traffic light systems. In the UK we use many Roundabout junctions , of varying sizes, a solution that enables crossing traffic without necessarily stopping the flow,They tend to be self adjusting as flow varies.
The cycle lane I've seen come closest to this 7500/hr is probably the Nijmegen Central station -> Campus route. Would be interesting to get an actual count there...
I have noticed in a lot of Dutch cities (also outside cities but to a lesser extent) the following scenario: I am stood at a red traffic light. The light turns green and I drive speed limit towards the next light. Just before I get to the next light, it will turn from green to red, forcing me to stop rather than allowing for continuous driving. In some cases, the light will then even turn green again within a second or two. I have noticed this quite a lot in the city you mentioned, Haarlem. This seems extremely frustrating and wasteful to me because it forces unnecessary stopping and starting which causes extra brake wear and fuel usage. I understand that many Dutch traffic lights have proximity sensors in the road so that the lights turn red when there are no cars coming but still the way this is often timed is a bit frustrating. I was wondering if this is just poorly timed lights or whether there is indeed a good reason for this. My suspicion is that the intention is to slow down cars going through the city to make traffic safer for cyclists and pedestrians but I'd love to hear some genuine insight on this.
I'm a car-free road-diet advocate, but I'm not convinced by the apparently argument that street width doesn't matter. Frequent traffic lights cut road capacity, sure; naively they would cut it from 1800 to 900 vehicles per lane. But you would still have benefit from having 2 through lanes instead of 1, or 3 instead of 2. I have done my own traffic counts locally, and have gotten 10 cars per minute per lane for a 4-3 converted street (one lane each way, plus turn lane; all wide), and 8-10 cars per minute per lane (usually 8, but 10 one time at 5 PM) for the baby stroad (2 lanes each way, plus turn). The more-lane street is in fact passing more cars, 960-1200 per hour. (Granted, I have not counted on any 3-lane in a direction streets, don't have one handy.) And yeah, 1200 per hour looks minimal compared to 1800 on an uninterrupted lane, but the intersections are a given. What I see is not "more lanes don't help at all" but "the extra lane would do more good as a bus lane, bike lane, light rail lane, etc."
Your alternative is generally the intent because in most of these use cases there is no opportunity to expand the road. It's already used all the space it can get. However, there can still be some side effects that ideologues might not be dispositionally inclined to take into account... like people using side streets instead. My city is horrid with intersection management, and that overwhelms whatever else they try to improve.
Well, considering how different traffic lights are in the US vs NL and how intersection design differs because of this you can imagine intersection capacity in NL is a lot higher, and it's not even funny by how much. I'll let Ontario Traffic Man explain (Ontario, Canada uses the same signal style as the US): th-cam.com/video/7KPGVP85WpU/w-d-xo.html Now, add sensors to the mix on top of the timing differences (because even with sensors the conflict resolution has to be preserved) and you see how the capacity increases by simply ensuring once a vehicle is noticed it'll almost always get a green light by the time it hits the light itself.
We recently reduced a 4 lane divided road to a two way divided road with protected bike lanes. Yet kept an unwarranted signal due to political pressure. The protected intersection geometry negates the need for a signal but people are so scared to not have a signal. I was so frustrated we gave in!
If the problem are intersections, then build more roundabouts and narrower roads!! The flow will significantly improve!! The US is ridiculous with it's 26 lane highways!!
I am a Nor Cal guy myself and lived in the Netherlands for more than 5 years. I miss California for the physical geography and the Netherlands for the social geography.
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"In cities we can't forget about transit."
USA: Are you sure about that?
Houston: challenge accepted
You can't catch me rational thoughts!
@@rishabhanand4973there are actually some transit lines in Houston and it’s expanding
@@Takoma420That’s awesome, hope they keep expanding it
Republicans will NEVER use public transit of any kind. 😂
Reminds me when I played "Cities Skylines" and noticed that I can fix a lot of traffic problems by fiddling with the intersections.
Exactly. Intersections will always be the bottle neck. In my opinion, besides minor increases from fiddling with things like lane arrows, it is either splitting traffic up so multiple intersections can handle the load or it's removing intersections altogether.
Lol I started playing CS again and yes you better get those intersections right the first time or you will have a headache come population growth.
Turns out that, yes, you do need a six lane road through your rural village if you end up halting traffic every half mile with traffic lights.
I played first one just because i wanted to do perfect super insane trafic, but even with mods the game always screwed me with something that was not possible or how it worked like how cars change lanes. But i defienetely made some sick solutions that should work IRWorld.
Actually CS is great for visualising the very point of the video as adding more lanes almost never helped in anything, but I was able to get 89% flow in a 540k city just by being careful with intersections and avoiding traffic lights at (almost) any cost. (Robust mass transit alone got me to only 65%)
Not gonna lie when I saw this video and the name of your channel... this was not what I was expecting. I fully expected a 'serious' one more lane video. I'm pleasantly surprised.
LOL, thought the same thing🤣
same
I'm honestly a little disappointed. I was kinda into the idea of an evil version of Adam Something.
@@Iknowtoomuchable after the internet video... that's Adam himself
Definitely. I would love to see him rambling about the NACTO graphics ;)
I don't understand how traffic engineers don't understand how the problem isn't capacity with roads, it's throughput. All of the stroads in the US are actually under capacity but have huge bottlenecks. That's what creates congestion. Adding more lanes adds more capacity, which we don't need, and doesn't solve the bottlenecks.
Bad training and bad standards. And a legal system that threatens any engineer who risks doing something less stupid than the standards. My half educated opinion only.
But if an intersection cycles and it has four lanes across, then four times as many cars can cross it during that same cycle as if it had only one lane. So while you might have to stop at intersections, a higher volume of cars would pass through it, the more lanes you had. If they had to line up single file, then it would take four times as long for those same cars to pass through the intersection, and/or only 1/4 of them would make it through during that cycling of the intersection.
@@timogulthat's the point: if intersections are sufficiently far apart, you don't need to build the road between with the same number of lanes as the intersections, it can be reduced.
@@thebigmacd In theory, but the number of intersections tends to depend on the need for cross traffic, not on the efficiency of the feeder roads. You can make very complex arrangements where one road only has three intersections across its length while parallel roads on each side have ten intersections along the same length, so that people loop around to their target destination, and sometimes this is efficient, but you will rarely end up without any benefit to having more travel lanes. There will usually be a point at which travel will back up to the previous intersection, and that is the point at which more lanes were needed years ago.
"Nonono, we just need one extra lane, that will solve the problem"
This one is bookmarked. I've been trying to explain to people that throughput is constrained by intersections for years and now I have an actual qualified traffic engineer saying it on the record. Along with a bunch of other counter-intuitive things such as how reducing lanes can increase throughput by allowing you to remove the signals from a signalised intersection. Perfect!
That would only work during extremely low use periods, or for cross traffic. It would not lead to higher _overall_ throughput in a high use system.
@@timogul Yes, you wouldn't be able to just remove the signals from an intersection of two major roads where traffic flow and turning rates are high in all directions.
But we have to put signals in where a minor side street meets a four lane road, even if there are only 100 turning movements per day, because turning across two lanes into another two causes too many crashes. Reducing that to just one in each direction and removing the signals is an easy win.
Of course another option is to block off the minor side street (and most others from the neighbourhood) so that everyone must leave via a single route. That also reduces the number of signalised intersections at the expense of making the start of people's journeys a bit longer/slower.
@@Ladadadada Again though, if the road sees a reasonable amount of traffic, then it is better to have two or more lanes, even if they have to pause at a light every now and then, than to have only one lane. Having only one lane would mean that the whole thing would back up much further. It ONLY works up to a certain amount of "cars per hour," and no further, whereas multi-lane roads can scale up indefinitely, and only become slightly less efficient-per-lane with each lane added.
Basically, Lane+1 is more efficient than Lane, but less and less efficient than 2xLane, so long as the number of people using the road is sufficient to keep the bulk of each lane occupied.
But yes, like I said, you _can_ just reduce the access points to the primary road. Have the primary road only include a few intersections every mile or so, then parallel to that you have another road that would have intersections every block, so people on the cross streets would feed into that second road, which would move slower on average, then cut across to the faster road to cover the longer distances. It makes shorter trips slower and less convenient, but keeps longer trips faster.
This is often how subdivisions work.
@@timogul as they already addressed your points directly I just wanted to add. Even in tines where it wouldn't lead to an increase, it would almost never lead to a decrease in flow as most intersections can only handle a little less than one car lane worth of traffic per hour anyway.
@@cherriberri8373 That's not true at all. I think if that is true of any scenario, it would only apply to a "fair" intersection, one in which all angles are given equal weight. Typically you would not do this. Typically, if you increase lanes above two, you would only do this along one road, not every road that intersects it, and the intersecting roads would only get their turn less than half as often as the main road. In this way, several lanes worth of traffic would sail through that intersection each cycle of the light. You might occasionally also have two such roads intersecting, but this would be the exception to the rule, and would at most back up occasionally.
"if there's one thing the Dutch hate, it's having to pay for something that provides no benefit"
I feel so called out right now 😂
Shouldn't everyone hate that? 😁
@@Strideo1 The dutch are famously cheap
The Dutch, the Scotts, the French and another group of people who if I mention you won’t see this comment.
“As an American who works in the Netherlands”. That explains why the video is published at 4am EDT. Love your videos!
@@chefnyc 👉👈🙏
@@buildthelanes Did you have to become a dutch citizen or have you been able to keep your US citizenship?
netherlands* u mean
@@commandbrawler9348 The Netherlands.
Why do Americans always insist on using timezones nobody knows? Just give it to me in UTC, please!
Structural engineer here. It's strange that traffic engineers take only ONE course on their field of study. I took 14 courses between undergrad and grad school. Since traffic engineers are taking such a broad range of courses, like hydraulics and structural, I can understand why safety factors are so deeply instilled into their work. But unlike structural engineering, traffic engineering deals with a human variable that doesn't seem to be captured in current practice. If I design a wind girt (beam) to support a huge wall of glass, I can make the beam bigger and that doesn't change the wind pressure moving past my building. It does make the structure safer because the beam is much stronger than it needs to be to resist wind pressure. Whatever infrastructure I put in front of the wind doesn't change the behavior of the wind itself. The governing wind pressure, which you design for, is constant. This is not so with street design. The infrastructure you put in front of a car driver changes the way the driver behaves: People drive way faster on wide, straight lanes. If you narrow the lane, it feels less safe to drive on, so people drive slower.
From my observations of the built environment, I think it's odd that we don't see narrower lanes in front of schools, which children cross on their walk to class. Instead, we put in wide lanes and 25 mph signs. Speed kills. And speed kills pedestrians. Why wouldn't you account for human psychology that is blatantly observed in your engineering design? It's also odd that we design so reactively. There seems to be a hyper focus on moving as much cars as possible as fast as possible. That's the driving factor for every street, and if it's not achieved the transportation system will just fall apart, and there's just nothing we can do about -- we're always at the mercy of more cars and more cars driving fast. Why can't we design slow streets? And why can't we set a design limit for how many cars a street is going to move ... for forever?
I thought the "one course" line in the video was a joke rather than a serious comment.
Technically 1-3 classes. But most of the time just 1. Transportation engineering isnt a thing really, just civil engineering
Yeah they narrowed lanes all over the place where I live and now people just drive 2-3 feet over the double yellows and expect everyone else to move out of their way. There’s way more accidents now than before.
Visibility matters too
I feel humans are now so mentally over stimulated with smart phones that they become painfully bored when things slow down and will become agitated and aggressive even. I feel speed cameras on every corner and physical obstacles like speed humps are the only way force people to slow down.
Thank you for the impeccably executed video! Your analysis is spot on. "Goed gedaan!"
Thinking about roads in terms of their capacity is more of an American thing, I feel like. It kinda pidgeon holes you into thinking that more capacity = better, and by extension more road = more capacity. It kinda sends the signal that the road's only function is to move as many cars as fast as possible at all times under all circumstances. In reality, there are road users other than cars that have to either cross, or travel those roads, as well as potentially live near them.
And in reality, two lanes of traffic doesn't even move that many more cars than one lane. It can even move fewer cars if it's designed wrong.
"the road's only function is to move as many cars as fast as possible" Yes, I've run into a number of times that I've heard that as the thinking. I've challenged them with, "what do you think the best benefit to the city is?"
"two lanes of traffic doesn't even move that many more cars than one lane. It can even move fewer cars if it's designed wrong." Yes, that has been shown by those who study traffic. My hometown used to have 4 lanes going through our downtown, and allowed left turns at every side street. It redesigned the road to be 3 lanes with a turn center lane that also restricted the number of left turns that could be made. Traffic flows better, and there have been fewer accidents downtown - which also improves flow.
But, but... bigger is always better!
@@rodshop5897 that sort of setup sounds a lot like my town except that we already have a middle lane with the four travel lanes. I really wish we would just fix the scar through our town, but instead we re paved it recently all while they're trying to make downtown a nicer, slightly more walkable area. I feel like we are trying to appear like a lot of the small towns nearby which ACTUALLY did something to increase walkability, but all the rich NIMBYs with their giant SUVs and trucks demand to see zero actual change
@@cherriberri8373 Yes, for our town, the lane narrowing and limiting of left turn options helped to slow traffic down a bit, while still allowing unimpeded traffic flow. Now there are more parking spaces along the road, which invites more people to stop and shop downtown. It's helped our downtown businesses and lowered the number of traffic injuries.
Car ad: Good enough, is not good enough for you. Because you want more, you hunger for it. Bigger. Faster. Stronger. The all new super max ultra Vroom.
(Quickly read disclaimer) *due to being extra wide this vehicle is not legal on all roadways. We are currently bribing politicians to build wider lanes. May be legal by 2026.
11:47 "I could spend the next hour talking about problems with this document"
Please do!!! I'd love to hear all about it and I'm sure I'm not alone. For us non-civil engineers, you are our only source for thougtful, intelligent, apolitical, fair-minded, dispassionate discussion on topics like this.
Maybe you could make a video on what the changes you propose would look like for the three intersections you studied before? I think it would be helpful for people to see what it looks like, what it would do to traffic flow (not much change) and how much extra space is created by bringing down the number of lanes between intersections.
@@rvdb7363 he might not have enough time for that. But maybe Streetcraft can help out with that.
I think the point is that the intersection isn't really a problem, but the road width in between the intersections is. It's too many lanes for the "intersection capacity".
@sheepje yes I understand that. I just thought it would be helpful for an international audience to have a visual of what the changed situation would look like in an American context. When I comment on American urbanists with examples from my own city (Utrecht - the Netherlands) I often get the reply that our solutions would never work in the USA. A redrawn map and/or simulation of traffic flow of what actual American intersections might look like when redesigned to be one lane each direction might inspire people to think more out of the box. Reducing the number of lanes would create space for sidewalks, protected bike paths, more green etc.
I am someone non-professional, just interested in this topic, living in The Netherlands. I have the feeling the bigger picture plays always a much bigger role for the traffic design than just the street design itself. As a cyclist I don’t even care if the tarmac is red.
The thing is, the entire traffic situation could perhaps be improved with replacing 3 signalized intersections, with just 1 signalised intersections and two detours to reach the other intersections, which then don’t need signals anymore. That one intersection can then be upgraded to a turbo-roundabout with non-level crossings for cyclist/pedestrians, or non-level intersections with exits/entrance towards a roundabout. The entire section between the three junctions could then have service streets next to the main road. These servicing streets convert the stroad into a road. The main road is then one lane in each direction. The service streets will be lower speed, suitable for cycling, and suitable for servicing the exits of neighbourhoods, companies, stores etc. Additionally, they could be even made one-way traffic.
This high-level planning is often not covered in the urban planning video’s. But from my youth I always remember the safe cycling routes not to be ‘red tarmac cycle streets’, but ugly converted streets to low volume traffic, with a lot of exits and street parking. This low-cost conversion with a high-level plan, in my opinion this is where it all started in The Netherlands. This involves neighbourhood plans with one-way (two-way for cyclists), cutting streets and thereby convert 4-way junctions in T-junctions. Moving cycling crossings away from the main road intersections, if main roads are one-way lanes, with a middle buffer area, this makes it ideal and easy to cross for a cyclist or pedestrians often without signals at all.
This high-level design is much more important then all the nifty design details of expensive street-scapes. The aim is to have a better overall traffic flow, with sufficient access to each area. Would be VERY interesting to see some before/after neighbourhood design in The Netherlands in the 80s/90s, as well as some proposals to actual field cases in the US, for instance these junctions in the video.
Nice video btw! ;)
The channel @Streetcraft makes good videos to visualise street redesigning. Sometimes he talks about real projects and shows the results.
The "there's something for everyone to like in reducing lane count" is really interesting, theoretically. I worked as a civil engineer in the US for a bit (and don't anymore because it sucks), and the DOT I worked for wanted very badly to reduce lane counts - calling them "road diets". They often did trials of this via temporary traffic control, and while traffic throughput never really changed, public opinion was constantly massively against them. Sometimes they actually did the lane reduction when the road was rebuilt, often not. Drivers in the US constantly vote against themselves here.
Because many US drivers feel like they have the right to speed, and how are they going to dangerously swerve around you if there isn't a second lane? In reality the benefits of speeding are near nothing, and only makes the road more dangerous. Anyone who's ever timed how long it takes them to drive from point A to point B on a regular basis will quickly realize that speeding saved them a minute or two at best. You know what really adds to your travel time? Being stopped at poorly designed intersections.
Idk what it is about Americans voting against their own interests constantly, not that it’s exclusive to the US but still. My town actually voted down a proposal for a solar farm because it would “ruin the landscape”
They vote against them for good reason.
If you only have a single lane, you are beholden to the driver in front of you. If said driver wants to drive 18 MPH under the speed limit, you do too, whether you like it or not.
Having a second lane means easily getting around the idiots.
@@Shibouu59time is our most valuable resource, and speeding saves it. Definitely worth it
@@austinbaccusand two lanes are perfectly enough for that
One major advantage to having a second lane (but not more) is allowing a road to function even if a car lets a passanger on or off, or breaks down.
Also, no weaving and overtaking is good only until you stuck behind that old fart who drives twice a year doing 25km/h.
That function could be achieved with a paved shoulder, as is seen on many state highways in New Jersey.
Or if Grandma decides to do 32 in the 40.
I went on a trip to Hawaii recently, and the island I was on had one major road going, one lane each way.
Someone ahead of me decided they didn't want to do the 50 MPH speed limit, and decided to do a leisurely 40 MPH for about five miles.
By the time he turned off, there were easily 200-300 cars behind us (probably more, we couldn't see the end of the line). And in front of us there was nothing but open road.
This one guy managed to waste 7.5 hours of the rest of humanity's time, and the only reason it happened was because there wasn't a way to pass him.
One "benefit" of those extra lanes you forgot to mention is that they vastly increase the heat island effect in all of our US cities!
And less water absorption of the ground, so with heavy rain there's a higher risk of flooding! Awesome!
In my city (Utrecht, NL) a road near me was actually redesigned a few years ago. Two lane road, one lane each direction. The two lanes were made a bit thinner, to slow cars down a bit as they would often speed. The space that came free in the median became basically a ditch, so any water that fell on the road would go into the ditch and back into nature. It's super green, there's all kinds of low plants and flowers growing. And it's nice to know the municipality is future-proofing the city, as with climate change there simply might be more heavy rain after periods of dryness.
Not to mention my cousin the road contactor can buy a new condo in Malibu.
I feel like this single lane thing will be severely hindered in North America because people think they have a right to speed past others who they perceive to have what they consider nothing important to get to. Most car drivers believe theres multiple lanes because the right most lane is the idiot bad driver/semi truck lane, the middle lane is the speeding lane, and the right most lane is the super speeding lane.
But how am I supposed to get to Costco 1 minute faster?
@@Senthiuz Build it closer to your home, easy
Nobody wants to be beholden to an idiot going slower than they should be.
If you were stuck on a sidewalk behind a wheelchair going 1/3rd your speed, you'd want to get around him too.
@@austinbaccus too bad. We live in a society
This really reminds me about “the goal” or “the phoenix project” where one of the key takeaways was that it is useless to expand the capacity of the system anywhere except at the constraint, since everything would just pile up at the constraint. You’d think that it is obvious, yet this issue has been popping up all across a variety of engineering disciplines. Crazy to think about
So essentially, it generally makes more sense to think about urban street geometry from a qualitative perspective rather than obsessing about quantitative throughput. Awesome, real perspective shifter. I think we intuitively understand this when we advocate for wider sidewalks even when not strictly "necessary" for moving people around. We have to think of streets as places to be and not just serving conveyance needs. Subscribed, nice video
I can’t this hasn’t really been covered before- and it absolutely makes sense. Thanks for making this video.
Seeing arterial road “realignment” projects widening city roads to 2-3 lane arterials is even painful to see knowing that it’s essentially a pointless waste of money and wasted chance to properly redo the road.
If you have any resources to share that could help us spark these conversations it would be really great.
10:20 7500/2/3600 = 1 bicycle PER SECOND in each direction! That would probably be the busiest bike lane in the world.
In Copenhagen (Denmark)is it normal to so many bikes because the road is designed for it. There is it normal in rush hour to the lanes so filled that maybe 200 bicycles cross every time. But Denmark and Netherlands are also the bicycle capitals of the world.
That doesn’t sound at all extraordinary. Lots of one-way bike lanes can safely fit 2 bikes side-by-side, and where I used to live there were some bike lanes in the downtown (and through or near the university) that could realistically manage 3 or even 4 abreast, with safe passing space.
Even with single-file, 1 second is plenty of follow distance on a bike if you’re an experienced rider, and even if you’re not very experienced but also not going that fast. It wouldn’t be difficult to get 2 bikes/second on a busy single-lane bike lane/path (which would translate to 4 bikes per second if it’s a two-way bike lane/path or two opposite-direction one-way paths/lanes).
@@natbarmoreYeah, in theory… It doesn't occur in reality, startin with "safe distance" from the bike before you (min 1s), which basically at least halves the "realistic maximum"…
Oh boy, do I ever hope SOMEONE in Brighton & Hove City Council's Highways Dept watches your output. Our old city, which lies on the South Coast of the UK at the confluence of two valleys, was built for a dirty weekend a couple of centuries ago and definitely WASN'T built with current traffic levels in mind!!
Great buses, pretty good rail links, evolving cycle lanes, rubbish road junctions (no design consistency), inappropriate use of mini-roundabouts (Got Google Earth? This one is a classic 50°49'53"N 0°10'20"W). Mercifully, our bypass was completed before our economy died of boinkered stupidity.
Boinkered stupidity is my favorite new phrase of the day! Here's to hoping that the good elements of your infrastructure start outweighing the bad.
Hope? Do they have public meetings?
A mini roundabout would be there as a way of traffic calming an area. But I see that the surrounding streets don't have mini roundabouts until you get up to Cromwell road.
If you think the roundabout on Goldstone Villas is bonkers, try this one:
50° 51’ 31” N, 0° 5’ 41” W
No idea what could be the purpose of it, considering it was always such a minor crossroads, and currently half of it is blocked by parking spaces!
I visited Brighton this summer and was really surprised just how many cars were squeezed in, so many streets that have gone to such effort to keep two travel lanes in. I think I've never had so many near-misses 😅
As a wise man once said, you're not stuck in traffic, you are traffic. :)
Very true, when you are on a bicycle or motorbike (sometimes) you can just skip by it all!
Anyone who drives a lot knows going down the side streets is faster than taking the main stroad through town.
The side streets have only one lane in each direction, less traffic, and no shopping centers. Even if the posted speed limit is lower, it flows better and is faster than the stroad which has lots of stopping and tons of traffic. Taking back roads to get somewhere faster only works if those roads exist and in a lot of cases there are no back roads.
Instead of more lanes what we really need is more roads.
I block myself in myself 🤔
This fills in a blank for me for why Seattle has imposed "road diets" on several arterials.
One such arterial went right past our old place, and I have to admit I was skeptical of turning a four-lane arterial into a two-lane+dual left turn lane. But SDOT argued that the data supported it - they couched it primarily in overall travel times not increasing, and explained the fairly obvious and logical safety benefits of fewer lanes for pedestrians to cross, or for speeders - like myself, if I'm being honest - to dart back and forth between while passing each other.
And I've gotta say, this change 100% delivered its benefits as advertised. Much more pleasant street to walk along, cross, live near, and drive on - and genuinely, no increase in travel times.
BUT - my big unanswered question until this moment was *why* travel times would not increase, since it seemed to me that this figure would necessarily be a function of road capacity and demand. And this video just filled in that blank for me so - sincerely, I thank you for it!
Love this, and you've given me words to explain a vague intuition.
One rebuttal that could be included (if only time permitted) is the fact, unappreciated by one average 70-something American whom I otherwise respect very much, that lane capacity does not vary greatly with speed. The separation between vehicles at 80mph is twice the separation at 40mph, with the result that the vehicle count passing a point in an interval of time remains the same. This paradox, and overlooking the reality that driving 65 vs 55 affects total travel time negligibly, leads voters into asinine political incentives.
So much waste and so much unpleasantness.
There's also a fundung problem: state and federal funds are spent aggressively on high-speed roads, leaving very little for rural or urban circulation.
Your comment about increasing speed not increasing capacity is indeed very counter intuitive, but if you assume people drive with safe separations then it's true. Thinking about it a bit more, it occurs to me that if you take a given mile of road and double the number of cars on it then you halve the separation which means you halve the speed. This means that although twice as many people are trying to drive along the road the half speed means there are still the same number of cars pet hour as there were before!
Braking distance goes up with the square of the speed, so separation should actually be four times bigger at 80 mph than at 40 mph. Most people aren’t keeping that much distance though.
@monobryn64 true, and especially for larger vehicles following small vehicles! (Or small vehicles cutting in front of larger.) But if all vehicles are approximately the same, the governing process is reaction time: brake lights to eye through brain to foot.
Honestly, I would expect that the average practicing American engineer falls into this speed fallacy assumption... unless there's a specific table in a manual somewhere telling them in big, bold letters that it's NOT TRUE.
Great video.
One criticism:
Capacity under non-ideal conditions is important to consider. In Calgary, Canada, roads freeze and thaw like 40x a year, leading to a lot of road maintenance. Temporarily losing a lane on a one or two lane road means a lot. A road needs at least 3 lanes in total before its even feasible to work on one without losing the road.
Just use temporary traffic lights. How do you think they do maintenance on 1 lane roads? Yeah it's way less efficient but during road works of course it will be worse
Ok, but how often does having a short stretch of an urban or suburban road under construction cut off access except to destinations in the construction zone? How often in an urban or suburban area is there _not_ another road people could take to get where they’re going?
Sure, the alternate route might be longer, and it might temporarily put too much traffic on a side street. But for basically any urban/suburban street, you’re occasionally going to need to do repairs to the whole width of the street, so even with more lanes you’re _still_ going to have to figure out how to deal with that. Whatever strategies you have for dealing with having 3 lanes of a 4-lane road closed/blocked/torn up will work even better when 1 lane of a 2-lane road is closed/blocked/torn up.
(Added bonus: in many cases, repairing both lanes of a 2-lane road at the same time would take about the same time as doing one lane, so you could significantly cut the amount of time the road was under construction if you could just close or all-but-close the entire road.)
They're called "Traffic Lights" because they cause traffic
if all the traffic lights were broken at an intersection then there would still be traffic.
And not exactly light traffic.
@@skylarius3757 But it would flow more efficiently, especially when outside of peak capacity. No more waiting at a red light when there's nobody actually going on the other lights that are green. Roundabouts ftw.
Roundabouts are great, up to a point. When there is too much traffic you'll reach a point where a (well designed) signaled intersection has a higher thankfully throughput. But you need smart signalling and the correct direction lanes, you my even need to sync signalling across multiple intersections. There's a road near where I live (in the Netherlands) where the traffic lights of 7 intersections in row all communicate with each other to optimize the timing of the lights for the best throughout. During peak times traffic is still doable there, which it wouldn't be with roundabouts.
@@CycleCalm "specially when outside of peak capacity" uh yeah so when there's less traffic there's gonna be less traffic, is what you're saying?
finally, an urbanist who does not repeat the same old points. I really like what you said about the NACTO transit street design guide. I always had a feeling that there was something wrong and your explanation confirmed it
Insanely high quality video. I will forward this video to my NIMBY neighbors. Thanks!
I'm sure your neighbors love you
@@austinbaccus I’d love anyone who deprogrammed me out of car-centric zombie thinking
@@DefenestrateYourself anyone who uses "car-brained" unironically needs to get a life
Great video! I hope more people find your channel. I would like it if potentially you could make the video longer and dive more into the details at the end, but that's up you of course. In any case great video!
thanks! unfortunately i got stuck on this video for around 6 months due to life happening, but im hoping i can make shorter, more frequent and higher quality videos soon. Thanks for watching!
I like your point about the capacity in the NACTO doc. I think the figures are helpful in arguing that bike lanes and bus lanes have greater capacity and therefore if we expect the population to grow then we can accommodate more people in a fixed amount of space without needing to tear down buildings to widen streets.
And just to be clear- the Dutch don’t have any rules like “we can take a lane out on this street because the peak hour traffic is below a certain threshold”? In a lot of US cities it is common to say if a street has below a certain volume we can take out a lane because the demand can be satisfied by a single lane without creating traffic. But I guess there is no parallel equivalent in the Netherlands?
As a trucker in the US, someone I'm willing to bet you've never even considered, these narrow 2 lane roads make life more expensive. Truckers need the extra space to escape brake-checkers, make sharp turns, and get around hazards such as parked/pulled-over vehicles, delivery vans, road debris, or even pedestrians. The way Europe deals with these issues is by having truckers live in cramped bunks squeezed between their seat and trailer (US truck cabs are about 400% larger than European caps on the interior, allowing us to live VERY comfortably in the truck for weeks or months at a time). This means European truckers demand higher pay, either to deal with the discomfort or to pay for expensive hotels every night. If they demand higher pay, then the cost of transportation rises, so stores and vendors raise the price of goods to maintain the same profit margin. This is the primary reason it costs nearly 3 times as much to live in dense cities in the US (like New York or Los Angeles) than it does to live in rural and suburban communities with larger roads.
Urbanists never think about truckers when they advocate for removing highways and narrowing arterial roads.
As for traffic flow, EVERY primary road must have AT MINIMUM 4 lanes so that people going HALF the limit don't grind the city to a halt; something I've witnessed myself multiple times as a trucker.
This is wonderful. But there's a big problem. Unless you're one of the 3.5k people that watched this video, you won't understand this. And here's why that's a problem. I actually know an intersection exactly like this that I travel through near Arlington, Virginia. The road is one lane each direction but widens to two lanes each direction for an intersection and narrows back down to one lane. Nobody uses that extra lane, because if you do, (and I do), you'll get honked at, cursed at, and blocked for being that jerk that tried to pass everyone at the traffic light. It's the same problem with zipper merges. I was driving with a friend one day and I used the extra lane, and he said, "wow, you're one of those people." I proceed to explain the exact same thing you just explained. Their response? "yeah, but still that's so rude, just wait." The problem is not that people don't understand, it's that people refuse to understand.
Haha, I got honked at today for the same thing. And this was a person that was behind me as if I was wrong for not getting behind them as the road narrowed to one lane. So bizarre...
I'm confused as how the intersection works. The way is should work, is that one lane widens to two or three lanes (left-straight or left-straight-right) and there is only one exit lane in each direction. Does your intersection have go from one to two, intersection to two exit lanes for the direction and then merges back to one after that? If so, it's not that the concept introduced in this video is flawed in anyway, it just mean that the traffic design of your local intersection is shit. Which is not at all surprising.
@@tommihaapanen846 In the netherlands a lot of 1 lane urban roads widen into four lanes at the intersection: one left, two straight ahead and one to the right.
The two straight lanes than merge into one, exactly as shown in the video at 2:14
This works very well as it leaves space for the cars to wait and accumulate. Then then spread out again on the single lane.
So no, that intersection is designed correctly and people are reducing the efficiency of the intersection by only using one que-lane
Louis, which intersection are you referring to?
As an aside, my "holy grail" for road diets in Arlington is Glebe Rd. from 395 to Ballston. I hate driving that stretch because if you take the left lane, you'll get stuck behind a left-turner and if you take the right lane, you'll get stuck behind a bus, trash truck, etc. I have maintained for years that the 2x2 lane configuration is functionally obsolete and should be completely eradicated within the Beltway, if not further.
@@daandenhartog6950 Thanks for the clarification 👍
Moved from Ottawa to Haarlem this year. So cool to see all the footage of my new home :)!
Surely by now there is enough tracking of our phones to determine where transit really needs to go....
Very important point to also get car drivers on board with the idea of reducing the number of lanes: it will make car journeys faster and more fluid! Because you will be able to remove traffic lights, you will be able to make turns. Too many lanes causes every intersection to have a traffic light.
Are roads in the Netherlands currently designed with fluid traffic in mind?
In Belgium they seem to do everything they can to slow down traffic. Speed bumps, chicanes, 30 km/h zones, zones where you can't overtake a bicycle (makes sense - what's safer: a car in front or behind you when riding your bike?). Potholes are getting bigger by the day, but speed cameras are state of the art. What used to be a 30 min journey is now 40 min if you're lucky.
Probably because design is not a word in the Belgian language /s
So on the one hand, Belgium is pro-active in trying to reduce traffic incidents, which is good (and something which is still up to debate in North America for example), but on the other hand there isn't yet a mindset to implement safety from the ground up in the design of our roads because Belgian urban planning is shite.
So what we end up with is a battle against symptoms (traffic fatalities) with band-aid solutions (speed bumps), but no desire yet to fix sprawl or start to *formally* classify roads as roads, streets, etc.
Huge issue with one lane roads that is if there is any problem the traffic completely stops, multiple lanes allows for traffic to continue moving in the same direction. Real life is a thing, and while single lanes sound good in a bubble they don't stand up in cities that often have many different events all occurring at the same time.
And still, Dutch roads prove you wrong. You're looking for issues that don't actually exist.
@@therealdutchidiot How do they prove me wrong? How do you get by a stalled vehicle? How do emergency vehicles pass in a single lane divided road? What happens if fire needs to work on a roadside burn? Is the road closed completely? What about construction? What if there is a large event taking place on the street or road? I assure you these issues exist despite your denial.
@@Zanduras1 How do Dutch roads prove you wrong? Because within cities roads are never more than one lane per direction an the issues you're describing simply never happen. Ever.
@@therealdutchidiot Ahh I was giving you the benefit of the doubt, but I see you truly do take after your namesake.
@@Zanduras1 So here's what you do, right? You build a two-lane road, one lane in each direction. Boom. Every problem you could think of is solved.
There is also one other factor separate from traffic engineering that contributes to throughput and flow - driver (and pedestrian) IQ. Obviously this is subjective but the drivers here in Toronto are not only moronic but borderline malicious.
This video blew my mind.
I was so scared when a channel called "build the lanes" popped up in my feed. But I'm glad you're not someone who just wants more lanes because car propaganda xD
Me too. The correct title is "build the lanes right" but maybe that is too long.
This is my thought too
Same here. Is road guy rob a car propagandist? I thought this channel was too before I officially watched the video 😅
lanes are not just for cars people, build the bike lanes!
"One more lane", but it's a bike lane.
It's logical, really. All (exceptions?) systems are limited by the bottlenecks, not what goes between them.
For some of them, like bikes and pedestrians, actually reaching "full" capacity requires a concentrated effort by the people to go out there, unless we're talking very popular routes that can reach those numbers naturally.
Multiple reasons why you may want more than 1 lane:
A. Someone pulls over to let someone out of the car.
B. Someone wants to turn across traffic into a side street.
C. Someone is doing 20 under the speed limit.
Emphasising good alternatives to driving and in particular, protected bike lanes is good but being disingenuous and saying that there's NO good reason for a road to be more than two lanes wide is just agenda pushing.
driving in most british towns is not really like this-narrower roads and more curves than USA-but it's true, the town centers get fully saturated and at a standstill. The key metric has to be how easy it is to get people out of the busy patch / off the road wherever they are going.
THANK YOU! I live in LA and I spend more time waiting at intersections than I do "in traffic". I am convinced traffic in LA (at least non-freeway driving) is bad because of the incessant insistence for almost EVERY intersection to be controlled by traffic lights "for safety".
I've been a pedestrian, transit rider, cyclist, and driver in LA, and I can say for sure that ALL of them sucked when it came to waiting at intersections/traffic jams. Riding a bike on the streets was dangerous, buses stopped every other block, walking felt like stepping in an oven on a hot day, and driving was stop and go all day.
Americans shouldn't be allowed to design things @@veelastname
Nice video! I always appreciate your insights. The video I loved the most was the lecture you gave at CSU Sacramento. For this format, your sound design could be improved. If you are interested in improving your audio, it can be done cheaply. Look into getting a good mic (you really don't need anything more expensive than a wired SM58), an audio interface (like a Behringer UM2), a 1 meter XLR cable, a mic stand (mine just clips to my desk), and a pair of studio headphones (I've had luck with Sennheiser). You can get a lot of this stuff used. Record with Audacity software and watch a couple tutorials on using the software tools to improve vocal quality. Also Google "microphone technique" and read a couple tips about that.
Please contact me on my email. Ive been trying to improve audio quality with a new mic but i seem to be stuck
Cool to see you use clips from Dutch cities! Immediately recognized the Rotterdam shots and the shots from my Schiedam neighbourhood 😊
Love the video! There’s a stroad in my town that goes right by the local high school, 5 lanes of traffic (two in each direction and one turn lane) and a massive car dealership on the opposite side of the street. TECHNICALLY there is supposed to be a school zone of 30 mph for driving during the week and the normal speed limit is 40 mph, but the road capacity easily can handle 50 mph. Next to a school! This one road is also the main arterial that runs through town, so the road is constantly facing through traffic that could easily shift to the highway just half a mile westward.
I’d like to see the road cut down completely-one lane in either direction, separated bus lane for students and for people going northwards to downtown, and a bike path for bikers to school and work. Will traffic be slower? Maybe, but that’s the point-it’s a school zone!
A positive side effect of changing to single lanes will also be that North Americans would learn and finally get used to merging properly without collective road rage outbreaks 😂
The concept of 'traffic flow' is lost to many people. Car drivers will want to emulate a laminar flow, but instead it's like water droplets trying to overtake and crash over one another. The latter is the definition of a turbulent flow. Psychology plays a major factor in traffic. To a severely underestimated degree.
I moved from a big city in the Northeast to suburbs in the PNW and I immediately saw the problem with road design. stroads and arterials dominate. There is no way to turn left without a separate cycle of protected left turns. There are no alternative roads and detours you can take that you can get with grid pattern and multiple parallel roadways like in many cities that can help spread out traffic. This piles on top of lack of transit, non motorized options and zoning systems that help make traffic worse.
I haven’t been this excited watching a new video from a new channel (at least to me) in a while. You are approaching the problem from a perspective which makes sense to me - queueing theory, which I think too few people are familiar with, I’m no expert but I have passing knowledge of it, as such I sometimes wonder while walking around town how would one model traffic - what’s the throughput, arrival rate, processing time, where are the bottlenecks, etc. I’m no traffic engineer, so it remains a curiosity, but I would love to explore those questions, the revelation between the steady flow of a country road and stop and go of a city caused by intersections (though in hindsight should have been obvious) feels like it opened a third eye for me, I don’t think I will look at roads the same way.
Even if the theoretical throughput of a lane of traffic is 1,800 vehicles/hour, I feel like it's important to bring up that the theoretical throughput of a lane of intersection is going to be significantly lower than that. At best, any given lane is going to average 40% of 'green light time' while at an intersection, which brings theoretical throughput down by 60%- though in practice it would be significantly lower than that as you have to accelerate from a stop which is going to cut into the number of vehicles you can get through each green line at an intersection.
You strike an incredible point on the realistic balance between 'Orange-pill' urbanism and car-first infrastructure. I particularly like your point about the size of sidewalks not increasing the capacity, but improving the quality of a system for everyone involved. As a traffic engineer, do you have any insight into how best individuals can influence their cities to build smarter infrastructure like you explain here?
Also, a more technical question on your laminar flow approximation of traffic. I'm a MechE student myself, but I've often thought about traffic engineering. Do you think a theory that roadways with more turbulence are more dangerous has merit? In that I mean is there some combination of factors of vehicle density, speed, and length in which something akin to a "Reynold's" number can be calculated for a roadway, and then with that an estimated area where traffic would become viscous, and therefore more dangerous? The only thing holding back this theory is how you could assign a viscosity to traffic flow.
Great video! I've been trying to say this to others on urbanist communities who generally solely seem to only circle jerk the "muh induced demand" phrase ad nauseam without providing much discussion on road design itself. Good road layouts / designs / geometry doesn't only benefit pedestrians and bicyclists, but it is also for the benefit of the driver. Most urbanist communities fail to provide this crucial messaging that the opposition would have a harder time arguing against.
Talking on a tangent - for things like controlled access highways in urban and suburban areas, a lot of lanes just lead to levels of complexity that humans cannot handle leading to crashes... leading to traffic jams.
Finally there is someone stating facts about the NACTO scale. As a civil engineer I hate the way that urbanists think that reducing lanes everywhere and building different infrastructure automatically increases use of bike paths or public transit. As long as the comfort, safety and especially speed of the mode of transport allows it, people will take that set mode of transport. Are bikes faster? Bikes are the answer. Is the car faster? Cars are the answer. You can't make a society but you can always facilitate everyone.
Actually, that's exactly what will happen. Most people choose the most convenient way of getting somewhere. Within cities there's absolutely no need to make the most convenient mode the car, though there should still be capacity for it.
Ignoring choke points, why they are choke points and just increasing more flow towards it obviously just creates more problems. Imagine if you engineered anything else so mindlessly.
Generous of you to call it engineering
As an avid driver and car lover, I would LOVE for more public transit and better alternatives to driving. Cause people who don't like to drive tend to suck at it.
Giving them an alternative would get them off the road and out of my way. My road rage goes away, and everyone is happy. Yay.
The double-edged sword with road hierarchy is that everyone is forced to use the same roads while the other, surface roads have very little traffic.
The best way to do it is to have options. At least one lane for every direction of travel on a road, and multiple routes you can take to get to your destination.
Grided cities worked a lot better in American cities than they do now with a single arterial road everyone now has to use.
This ignores that stroads are typically not simply routes for through traffic, they are also dealing with cars entering and exiting large numbers of destinations along the stroad. Cars pulling into and out of these parking lots and driveways by necessity are going at speeds much lower than what would be desired for steady state flow, and their sudden entry onto roads (often from poorly designed interfaces with poor visibility) poses risks to traffic passing through. Ideally you would have a proper road (which would have minimal intersections btw) for high speed, long range transit which would feed into dedicated slow speed, low capacity streets that service the various destinations. Stroads, pretty much by definition, are a compromise between these two attempting to do both. Additional lanes aren't there for maximizing capacity, they are there to allow cars to move at wildly different speeds simultaneously. If you take a two lane road, add on two right lanes for slow merging traffic and a shared central lane for left turns, now you're up to a 5 lane stroad with no additional capacity. Now stroads are a bad compromise that create lots of problems - greatly varying traffic speed is dangerous for motorists, extremely wide roads are terrible for walkability and pedestrian safety, the lack of a proper road creates congestion, large numbers of innefficient intersections are unavoidable, and they are expensive to build and maintain - but the design of stroads must be evaluated in the context that demands the stroads. If you eliminate those 3 extra lanes that aren't providing any capacity, essentially turning the stroad into a road, it is no longer able to accomplish the street functions that are necessary due to the absence of proper street infrastructure. Eliminating the need for stroads is a much harder challenge, but it is critical to see the desired improvements to quality of life.
Sounds like a cars need to pull into traffic faster
5:11 For non-engineers and non-Americans, it really IS true that the U.S. university system only leaves room for civil engineering students to take about 1-4 classes in their actual career field after all of the mathematics, general science, computer, elective, and cross-disciplinary "breadth" course requirements are satisfied.
Interesting, that reminds me of my husband's experience in law school which taught him to pass the bar, but didn't teach him much in his specialization. It is expected that attorneys will be training on the job for about the first 3 years.
This explains exactly why the only areas on my commute to work that are consistently backed up are bad intersections.
I have just checked up on Danish calculations. The free flow capacity on a 1 lane road is estimated at 1800 vehicles per hour. On 2 lane roads it is 2200 vehicles. A 2,5 meter wide bicycle lane has a capacity of 3000 bicycles an hour.
With cross sections and traffic lights these numbers reduce significantly.
I suppose this is why roundabouts are popular among road planners. It is in most cases much more effective than a traffic light.
Bicycles can easily blend in bicycle lanes, while cars have more problems. Still, roundabouts are generally much more effective. As shown, additional lanes do not help much when you have cross traffic. I suppose more than two lanes in towns are in most cases contra productive, especially with undisciplined drivers like in the USA.
My own anecdote experience is that in Germany on highways (Autobahn) drivers keep to the right and faster cars can pass on the left. But in towns with 50, 60 or 70 kph restrictions hardly anybody keeps to the left when there are two lanes. They pick a lane from the start and stays there when they are going to position them selves 2 to 3 km later.
Even though it is taught in driving lessons, blending like a zipper is not followed by many in Germany in towns and cities. So people fear being caught in the wrong lane. This is possibly the main reason why 2 lanes has almost insignificant higher capacity than 1 lane in each direction.
Was not expecting to see a clip of Yonge and Davis in Newmarket (my hometown) at 11:54, wonderful video!
I love how your first example show that a dual carriageway two lane road would more than suffice to swallow all of the traffic even for the most busy intersection. All those extra lanes? Rolling parking space.
Another great case study where a lot comes together is the veldmaarschalk montgomerylaan in Eindhoven, 2x2 highway converted to a 1x1 road with a 1x1 bus corridor which also functions as an expressway for emergency services into the centre, intellegently coupled signalling systems, and a multilevel crossing with the inner ring road.
This is literally why I never will move to a different country than the Netherlands. Growing up here you take it for granted but once I visited other countries, every time I was stunned by either how unsafe/dangerous it was or how impossible it was to get around without (or even with) a car.
I live in Kansas City and they've cut some urban residential streets from four lanes to two recently, making room for street parking and bike lanes. They've done this is a few more midwestern cities as well, along with adding double diamond interchanges and roundabouts. There's a bike lane outside my apartment now, and in five years here, I think I've seen two people use it. Still, cutting down the lanes makes sense given the throughput element and its relationship to intersections. I like having lots of lanes - KC has more freeway per capita than any other city on earth, and I love getting around here - but it's a luxury in most cases.
This is a lot better than what I usually see from MMT channels and I'm subscribing.
Yes yes yes. The bane of my life though is calculating stopline capacities in cities - mixing the theoretical and the observed. As a fellow transport planner (and traffic modeller) - I salute you!
Do roundabouts allow more throughput at intersections than lights? I feel that yes, but what does the transportation science say about it?
As I understand it roundabouts aren't made for throughput (it's usually not mentioned as benefit of roundabouts) but for safety as well as better traffic flow. Cars don't need to wait longer than necessary, as soon as there's a gap they can enter the roundabout. Though this relies on a gap existing, so intersections are better for heavy traffic because the traffic lights guarantee an upper limit to the waiting time. If I had to guess I'd say the throughput isn't really much better but the minimized waiting times can still accelerate traffic on average.
Yes, as long as you don't put a traffic light in the middle. Then it's twice as bad
I don't have a scientific explanation, but I think it really depends on the amount of traffic as well as the size of the roundabout. If there's too much traffic, you might have to wait at a roundabout for a long time. Maybe shorter than with traffic lights, but because it's not controlled it can feel longer. In the Netherlands cyclists and pedestrians often have right of way on roundabouts. As a driver you're waiting both for cars and cyclists on the roundabout when you want to enter, and again wait for cyclists when you want to leave. If there are a lot of cyclists using the roundabout continuously, it can create traffic jams. In my experience here in NL, roundabouts with significant amounts of traffic are often placed near intersections controlled by lights, so traffic from different directions basically come in waves rather than continuously.
Of course having to wait at a roundabout for a long time can increase risk of accidents, as drivers might decide to quickly jump in front of other traffic. In NL traffic lights for cyclists nowadays often have a button that lights up saying "please wait" or something like that when you arrive. Pushing the button or riding over magnetic strips on the road activate it. Often it doesn't change anything to the operation of the intersection, but psychologically it makes cyclists wait for green more often, as they know they'll get green sometime soon anyway.
Roundabouts are great for roads with one lane per direction and even flow in all directions. It also makes turning left very easy.
Two or three lane Roundabouts don't work so well. Also if the traffic is very high from two approaches. Vehicles coming from the other directions will have issues entering the roundabout.
Look on TH-cam where there are good simulations of just this with throughput numbers.
Roundabouts are split into simple one lane, double lane, dual roundabouts, etc. up to the "magic" roundabout. They are in general more efficient for local traffic than lights, but less efficient than say a diamond interchange.
The flow goes something like stack interchange/double crossover diverging interchange > diamond interchange > double roundabout > single point interchange > simple roundabout > drivers waiting/figuring it out on their own > simple lights
The exact ordering can vary by simulation, as some don't include pedestrian or bike areas, and can also be affected by local terrain and the presence/absence of public transport and truck traffic.
Glad to see a new video of yours, I really enjoy your content!
The nearest big city is doing road diets, permeant protected bike lanes as well as a light rail. It was argued by Warren Buffett that they should improve the bus lines first because currently they aren't just bad... They are literally unusable for everyone though some poor souls have no choice. My question is when it comes to down sizing roads or putting in a light rail should they not also work on the buses? I agree with Buffett that I think the bike lanes and light rail would get more use if they improved them first. But Wanted to know your opinion as well (if the city is important it's Omaha.) Also, I'm a driver that wants less fools off the road and am more than happy to patiently drive around public transit if that means they are! Besides sometimes I do not want to drive.
I live in Bristol, in the United Kingdom, and I never noticed it before watching this video, but we actually have a lot of roads that are single-lane that widen to two or three lanes at an intersection, and double-lane roads that widen to 4-5 lanes at the intersection.
One problem I've noticed a lot while driving is that our single-lane roads (of which there are many, because our infrastructure has to fit in cities that were built long before cars existed and in some cases follow a street plan that was decided in the middle ages) cause, is that it makes it extremely difficult to keep traffic flowing in cases where a vehicle needs to stop, such as to turn off into a side-road, or get around a bus that has to stop to offload passengers, or even just a vehicle that breaks down. Having a second lane allows overtaking in these instances, but is very much a luxury.
Solid video all around. I know in my city, we have way too many traffic signals, simply because the streets approaching the intersection are multilane, and going to one lane in each direction would immediately disqualify the need for a signal at all. Also glad you brought up the theoretical capacities of bike lanes/sidewalks/etc, it always felt weird using Streetmix for example and seeing these wild capacities if everyone gave up their personal space and comfort. Like yeah a bike lane can move more people on a congested street than a car lane, but I’m trying to make a safe dedicated lane here, not too concerned with this full saturation throughput lol.
Been saying this for years. Flow is more important than capacity. Especially when my city council was hell bent on building 6 lane monstrosities that stretched only 600m to the next intersection and then narrowed back down.
1:03 It is not strange because the rest of the world. urban always different from the rural .Except in the United States
Loved seeing my town show up in a random video on TH-cam. Very interesting video.
Heavens above! Finally something I had been thinking about for a while. I read that Denmark or Sweden found two lane roads were best and safest. Now I can visualise that.
Our Government is building RoNS - Roads of National Significance and RoRS - Roads of Regional Significance. They will be two or three lanes in each direction. This is going to cost Billions more than two lane roads (one in each direction), and it makes it more dangerous as our appalling drivers see this as a contest to use the road to get ahead of other traffic. Our road toll (deaths from traffic crashes) per capital is one the highest in the developed world.
This is not a Banana Republic!
It’s NEW ZEALAND!
Your high road toll is probably more to do with over-policing speed with cameras everywhere. Like in Australia you'd be better to stop doing this and focus on the over 65 category that is the most dangerous by far.
10:19 i thought it was obvious when ive seen this graphic that its talking about maximum theoretical throughput, obviously you wont actually get those numbers except under extreme circumstances. I think its still useful when people talk about how cars are "efficient" when they are so clearly not when compared to other modes.
So I like the video, nice to see actual stats to back up claims. But here in Toronto we have added bike lanes to almost every street, and traffic has gotten to a choke level, where the transit can't even complete their routes because buses can't get to the terminal.
sooo.... What do you think of videos from Vietnam where everyone just slowly proceeds into a completely uncontrolled intersection and goes wherever it is that they are going? Eyeballing it, the throughput looks nuts.
Also. My city has a number of intersections in close proximity where you have one entering and one exiting the intersection from each of the four directions and a large amount of pedestrian traffic. Currently it's a two phase light (N-S green and W-E red and then switch) with ped signals. What do you think of having one green going around clockwise (or cc, whatever) with the rest red with ped scrambles to facilitate pedestrian movements.
Spherical cows again, right? Road capacity is a very simplified model to look at a road that just doesn't work when applied to a complex reality.
Hello from Sacramento! I recognized so many of those stroads, especially Howe Ave. I have the misfortune of needing to drive on Howe once or twice a week. Sacramento seems especially bad about this, so so many stroads!
I will say this...I'm a mechanical engineer, not a traffic engineer, but I've heard the "capacity" or "volume" argument so many times that it was really mind blowing finding out that it doesn't really matter, even for bike lanes (which makes sense if you think about it even for a moment). I remember looking at an "active transportation plan" for the Pocket/Greenhaven area where the sections of Florin and Meadowview leading to I5 were shown as not eligible for bike/pedestrian infrastructure because, at 40,000 cars/hour, the traffic volumes were "too high!" (Another example of "we don't ever dare take space away from cars!"). I remember thinking how absurd that was on so many levels. And this adds a new level to the absurdity.
In any case, I'm looking to get out of here. I don't think California in general, or Sacramento in particular, will ever get it. There is just too many entrenched interests and too much money sloshing around in the political system to ever expect anything to change. Franklin Blvd. was supposed to get the "Complete Streets" treatment four years ago. They keep saying it's going to happen soon and then...nothing. Don't even get me started on how pathetic SacRT is these days. I'm looking at Delft as my final destination, if I don't get run over first.
The Netherlands changed because people got involved.
@@barryrobbins7694 Nederland changed because a solid plurality, if not a majority, of the public rose up and said no. And very aggressively at that. When you have a system where 85% of all trips are by car and most people don’t really know of, or can’t visualize an alternative, then you have a vast majority who are either indifferent or hostile to change. That is the situation in America today. The Dutch stopped before really even getting started. We have literal decades of entrenchment to reverse. And it’ll probably take twice as long to reverse the damage as it took to cause it. Simply “getting involved” won’t fix that. Today’s “advocates” are too feckless and would rather beg for bread crumbs and incrementalism than demand real change.
I’m pushing 50. The day when it’s no longer possible, or safe, for me to keep driving is coming, and probably sooner than I think. I don’t see America looking remotely like Nederland 20 years, or even 30 years from now. I don’t intend to be trapped in my house, experiencing cognitive decline, because I’m too old to drive and every other mode is unreliable or too dangerous. No thank you. Better to leave now while I can and move somewhere that I know is already safe and reliable for the elderly than bet on a future that is unlikely to happen in my lifetime.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. The United States is a dying empire. While China has evolved, the United States has devolved.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. The United States is a dying empire. While China has evolved, the United States has devolved.
@@ScramJett Sure, if you are about fifty you might not want to spend the time necessary if you won’t see significant change in your lifetime. Unfortunately, younger generations are left with all the problems that they didn’t create, with even less resources to solve them. Then there are the younger people that leave. It’s a downward spiral. China has evolved, the United States has devolved.
Great video! I never thought about that. Now I feel bad for using that source in my own video. Good reminder that we aren’t the experts. Still hate the Coomera Connector project tho
Really great video, this is something that's frustrated me alot about UK road design. So many of our roads (specifically the carriageways) are bigger than they need to be 'just because'.
There's one near me that almost looks as though it should be 2 lanes in either direction but is one (despite bottlenecks on either side 500 meters apart) so you end up with rediculous weaving and awkward queueing. It's like the planners wanted to "suggest" driving side by side but without drawing a dotted line to make people do it. It was recently resurfaced and every time I walk on the bumpy uneven pavement I think 'that's so much asphalt for no added benefit'
Trying to do Street improvement projects here runs up against the inevitable assumption that roadspace = congestion capacity, so as much as people are statistically on board, they still resent any space being taken from cars, even the useless space no one is able to use
What about emergency vehicles? Isn't it better to have two lanes so the ambulances can get ahead, and still leave room for other drivers to pull over?
Emergency vehicles have no issue navigating roads like these. And they can use an adjacent bikepath instead if the need arises.
This video is a great example of why simpler transportation systems seem to work better, and layering adjacent but not conflicting transportation modes seems to be better than doubling down on one. A boulevard with a light rail line, bike lanes, and sidewalks moves many, many more people than the same space with just cars and sidewalks.
Living in a city that has installed traffic lights in roundabouts, THANK YOU! It is nice to know that there are non-insane traffic professionals out there.
When my son was at Uni members of his course were given a task to 'prove' that traffic lights were better for flow than other systems. The research was of course paid for by a company that made traffic light systems.
In the UK we use many Roundabout junctions , of varying sizes, a solution that enables crossing traffic without necessarily stopping the flow,They tend to be self adjusting as flow varies.
The cycle lane I've seen come closest to this 7500/hr is probably the Nijmegen Central station -> Campus route. Would be interesting to get an actual count there...
I have noticed in a lot of Dutch cities (also outside cities but to a lesser extent) the following scenario: I am stood at a red traffic light. The light turns green and I drive speed limit towards the next light. Just before I get to the next light, it will turn from green to red, forcing me to stop rather than allowing for continuous driving. In some cases, the light will then even turn green again within a second or two. I have noticed this quite a lot in the city you mentioned, Haarlem.
This seems extremely frustrating and wasteful to me because it forces unnecessary stopping and starting which causes extra brake wear and fuel usage.
I understand that many Dutch traffic lights have proximity sensors in the road so that the lights turn red when there are no cars coming but still the way this is often timed is a bit frustrating.
I was wondering if this is just poorly timed lights or whether there is indeed a good reason for this. My suspicion is that the intention is to slow down cars going through the city to make traffic safer for cyclists and pedestrians but I'd love to hear some genuine insight on this.
Woah. I used to live right next to Roseville, and recognize those roads! I've also visited Amsterdam and became a radical YIMBY urbanist as a result.
I'm a car-free road-diet advocate, but I'm not convinced by the apparently argument that street width doesn't matter. Frequent traffic lights cut road capacity, sure; naively they would cut it from 1800 to 900 vehicles per lane. But you would still have benefit from having 2 through lanes instead of 1, or 3 instead of 2.
I have done my own traffic counts locally, and have gotten 10 cars per minute per lane for a 4-3 converted street (one lane each way, plus turn lane; all wide), and 8-10 cars per minute per lane (usually 8, but 10 one time at 5 PM) for the baby stroad (2 lanes each way, plus turn). The more-lane street is in fact passing more cars, 960-1200 per hour. (Granted, I have not counted on any 3-lane in a direction streets, don't have one handy.)
And yeah, 1200 per hour looks minimal compared to 1800 on an uninterrupted lane, but the intersections are a given.
What I see is not "more lanes don't help at all" but "the extra lane would do more good as a bus lane, bike lane, light rail lane, etc."
Your alternative is generally the intent because in most of these use cases there is no opportunity to expand the road. It's already used all the space it can get. However, there can still be some side effects that ideologues might not be dispositionally inclined to take into account... like people using side streets instead.
My city is horrid with intersection management, and that overwhelms whatever else they try to improve.
Was expecting you to also talk about difference in intersection capacity in the NL and the US. Would be an interesting comparison.
Well, considering how different traffic lights are in the US vs NL and how intersection design differs because of this you can imagine intersection capacity in NL is a lot higher, and it's not even funny by how much. I'll let Ontario Traffic Man explain (Ontario, Canada uses the same signal style as the US): th-cam.com/video/7KPGVP85WpU/w-d-xo.html
Now, add sensors to the mix on top of the timing differences (because even with sensors the conflict resolution has to be preserved) and you see how the capacity increases by simply ensuring once a vehicle is noticed it'll almost always get a green light by the time it hits the light itself.
We recently reduced a 4 lane divided road to a two way divided road with protected bike lanes. Yet kept an unwarranted signal due to political pressure.
The protected intersection geometry negates the need for a signal but people are so scared to not have a signal. I was so frustrated we gave in!
If the problem are intersections, then build more roundabouts and narrower roads!! The flow will significantly improve!!
The US is ridiculous with it's 26 lane highways!!
Well, yes, up to a point. Roundabouts are really easy to clog.
I am a Nor Cal guy myself and lived in the Netherlands for more than 5 years.
I miss California for the physical geography and the Netherlands for the social geography.
I’ve got a city councilman who believes the opposite so thanks for giving me the talking points to argue against him!
Great video. If you ever made a video on the comprehensiveness of the network like you referred to at the end I would watch it.
Nice one 👍