How Reflectors Work

I understand that you think blacking these out isn’t a big deal because your taillights are on or act as a reflector. But let’s take a closer look at how these reflectors actually work, because the way they reflect light is very different. See a taillight is meant to take the light from the bulb and diffuse it rearward - meaning the mirrored surfaces are angled to deflect light originating from inside the lamp. And newer taillights don’t have any of this - they’re just a bunch of LEDs. But a reflector uses a special reflection technique that’s very similar to road signs called retroreflection. We can use this light here as a makeshift headlight, and watch how the taillight doesn’t reflect much light but the reflector is super bright. On road signs, this is achieved with either glass beads or microprisms, reflectors only use microprisms. And the idea here is simple - they reflect light directly back in the direction it’s coming from. They do this by having two mirrors at 90 degrees to each other, so that unless light comes in from a an angle greater than 90 degrees, the light will be reflected directly back at the source. You can see that as I move this light around the garage, the reflector is still just as bright as it was from straight-on. That provides the most possible visibility of the reflector, and in this case, the most visibility of the vehicle or sign as well. Now you might be thinking that you always have your tail lights on if you’re driving, and statistically that’s not true, but even if you were perfect, at some point you’ll have to park your car for dinner or whatever it is you’re doing, and people are awful drivers in parking lots. And in foggy conditions, a reflector can provide extra visibility because the reflectors are generally located under the taillights, closer to the road where the warm asphalt will clear the fog.
Oh and one more thing - video clip of non-us-spec - that’s just simply not true, these are not only on global spec vehicles because of how much safer they are, but they’re part of the EU regulations.

[@aperson1181]

if your/my car does not have reflectors, can you buy an aftermarket tape and attach it to the back? Which tape and what is a good location?