[pixl97]

>In theory we would have safety experts analyze each road and come up with an effective speed that would be safe in optimal conditions

That would be nice, but it's important to recognize that 1/4 of accidents are weather related. Often that is because they were going over the maximum safe speed at the time, even though it was below the posted speed limit. Per the NHTSA only somewhere around 10 to 15% of accidents are directly related to speeding, the most likely cause of an accident is inattention.

[wlesieutre]

Ah, what we really need then are eye trackers in cars. Look off the road for more than two seconds? Ticket! Not watching your mirrors? Ticket! Change lanes without checking your blind spot? Ticket!

[nitrogen]

I believe I've heard of cars that will make an obnoxious noise if you appear to be falling asleep.