[w45yw45ywtg]

As a nitpick that I'm sure varies from state to state... All things can't be equal if you're going slower than the rest of traffic since by definition there's a speed differential relative to the vehicles around you. In drivers-ed in California for example the advice from the dmv is actually to go the speed limit /or/ keep with the flow of traffic. If everyone around you is doing 80 in a 65 zone then you should still speed up at least a little or move into a lane where the flow of traffic is slower. Automated vehicles interestingly are an odd case because no company is going to tell their vehicles to break the law even if social norms encourage otherwise.

[unshavedyak]

I expect it'll help - though. Ie reduce the average, making more lanes of traffic safer by body blocking the speeders.

Though, I do expect there to be an initial surge of aggression when people are forced to reduce their speeds by 15mph.