"buttumes there is some way to determine how fast people would drive if there were no speed limit!" Now that's a stupid statement. Remove the speed limits from a stretch of road, and measure the resulting traffic. Surely even you aren't *that* stupid.
When do you measure the speed of free flowing traffic? At night? The middle of the day? During a rain storm? During peak traffic? In the winter? And how long do you wait after you remove the speed limit before you make you "official" determination? A day? A week? A month? Do you pre-announce what you are doing? I don't know about you, but it seems to me a lot of people tend to keep driving at the same speed for a while even after road contidions change. I regulary drive a stretch of road with a 70 mph speed limit. It evenutally convreges with another multilane highway that only has a 55 mph speed limit. However, a lot of cars keep right on driving at 70 for at least an extra 5 or 6 miles. So I buttume the average speed on the road leading up to the road where the free flowing speed is being determined might have an impact on the study.
I personally dislike the concept of the 85th percentile rule. It seems to me this has little to do with dertermining a "safe" speed and a lot to do with making enforement of overly harh speed limit laws more palitable to the majority of citizens. It is much eaiser to enforce draconian laws against a small minority, particualrly when that minority is composed of arrogant "it's all about me" jerks who harrbutt "average" (i.e., the majority of) motorists. I am certain that many "average" motorist inwardly smile anytime they see an expensive German or Japanes car pulled over by the law.
Ed
