> try driving in the left lane at the 55mph speed limit in NYS in areas around NYC Why the left lane? I used to live in NYC and when traffic was light enough t

> try driving in the left lane at the 55mph speed limit in NYS in areas around NYC Why the left lane? I used to live in NYC and when traffic was light enough to actually drive the speed limit I generally stuck to the right lane to avoid inconveniencing other people who wanted to drive faster. Wouldn't people with court-mandated speed limiters simply stick to the right lane? > Any attempt to force people to drive slower than the 85th percentile speed poses a danger to others on the road. Perhaps they'd need the "ATTENTION: This vehicle's speed is monitored by GPS" stickers that I occasionally see on fleet trucks in the city. Regardless, this seems to be an objection to selective enforcement methods, right? For example, if all drivers are subject to the same constraints (whether speed cameras, universal speed limiters, road diet, etc) then not only would this not increase discrepancies in speed, but it would likely decrease them. Does this mean you would support such measures? > Doing draconian things that are ineffective has an opportunity cost Agreed. But that applies to ineffective things whether or not they are draconian. I do agree that stoplight cameras have mixed results -- typically reducing serious T-bone collisions while increasing rear-end collisions -- but to be clear, when I said "cameras" I was referring to speed cameras, not red-light cameras. On the topic of NYS, their school zone speed cameras seem to have been effective at reducing injuries caused by drivers in school zones. > As long as the distance between vehicles remains non-zero, collisions are avoided. Efforts really should be focused on maximizing the distance between vehicles, rather than on minimizing the speed at which they travel. Due to human reaction times and the physical limitations of braking, maintaining a time between vehicles is more relevant than distance. That's why defensive driving courses teach you to keep about three seconds between your car and the car in front of you, more if you're hauling a trailer. If you're driving at 8mph that's only about 10ft, but at 80mph that's 100ft. So while I agree that increasing distance is useful, the distance necessary to ensure safe operation is a direct function of speed. I heard of a few cases in which so many drivers were already breaking the speed limit on an overengineered highway that raising the speed limit did not increase collisions e.g. in Michigan, Texas, British Columbia. But otherwise the data is pretty clear that making people drive more slowly improves safety.