Your information is not totally correct. There wasn’t traffic jams at just 3 of the tunnels, there were jams at ALL the tunnels. However, it was easier to bypass 3 of the tunnels than bore new tunnels. However, the other 4 tunnels were “twinned” to alleviate traffic congestion. If the other 4 tunnels were “unoffensive” then there would be no reason to twin them.
Your information is not totally correct. There wasn’t traffic jams at just 3 of the tunnels, there were jams at ALL the tunnels. However, it was easier to bypass 3 of the tunnels than bore new tunnels. However, the other 4 tunnels were “twinned” to alleviate traffic congestion. If the other 4 tunnels were “unoffensive” then there would be no reason to twin them.