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Old 11-26-2008, 01:20 PM   #22 (permalink)
jamesqf
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Quote:
Originally Posted by Christ View Post
If everyone in the world drove 2x as fast as they do now, there would be just as many cars on the road as at any other instant, but they'd all be there for a shorter time.
I don't quite follow your logic. (OK, I'm being overly polite, I really think your logic's wrong :-)) If (important point) trip starting times are random, and every car moves twice as fast, then obviously there'll be half as many cars on the road at any given instant. At the other extreme, if every trip starts at the same time, you'll have the same number of cars on the road at the start, but the number will diminish faster.

Of course the real world is somewhere between these two extremes - a lot of people do tend to leave work around 5, for instance - but I can see this in action on the local roads. I live off a 4-lane highway that's the only practical route between two populated areas. Even at rush hour, traffic normally moves at about 60 mph, and flows freely, so that it takes maybe 10 minutes for any individual car to get through the bottleneck. Let something - an accident or a snowstorm - slow down the flow, then it can take an hour or more to get through, and traffic will be backed up for miles on either end.
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