I'm always leery of Social Engineering.
I've seen where designating a special lane - HOV - backed up traffic in the other lanes, because it's simply not as convenient to car-pool.
Local city bureaucrats here have narrowed a couple streets and put goofy "bulb-outs" at many intersection corners, to "beautify" the town and "make it more appealing for walking".
Didn't do a thing for increasing walking, but it's doubled the drive time & back-up in town.
The people who don't know how to merge, who nail the brakes or rubber-neck for seemingly anything, etc are an issue.
Driving isn't taken as seriously in the US as it is in some other places (Germany, for example).
Nor are the roads and their maintenance: every day, I see something that's a set-up for a wreck or vehicle damage.