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Old 07-29-2009, 02:28 PM   #14 (permalink)
JacobAziza
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Quote:
Originally Posted by fidalgoman View Post
When you drive in such a way as to create turbulence in the flow, too fast or too slow
I hear that a whole lot, but do you know of any source to corroborate it?

Because from what I have read, studies actually show that the slower you drive, the safer you are.

"risk of involvement in a casualty crash, relative to the risk for a car traveling at 60 km/h, increased at an exponential rate for free traveling speeds above 60 km/h"
Speed and Crash Risk - Executive Summary

“First, the probability of a crash is approximately proportional to the square of the travel speed. Second, in a crash, injury risk is approximately proportional to the impact forces on a person, which in turn are proportional to the square of the impact speed. These two effects can be summarized in a general rule of thumb: When travel speed increases by 1%, the injury crash rate increases by about 2%, the serious injury crash rate increases by about 3%, and the fatal crash rate increases by about 4% “
Traffic Safety Center Newsletter Winter 2008, Volume 5, No. 1: Traffic Safety Culture: the role of speed

These studies were looking at overall statistics, and therefor should inherently take traffic flow into account.

And while it may seem counter-intuitive at first, I think this is the results we should expect.

For going slow to cause an accident, it would mean someone coming up behind another car, at a low relative speed (if car A is going 55 and car B is going 70, their relative speed is only 15) and somehow fail to notice they were getting closer all the way until impact. I suppose if cars are passing in other lanes, it makes slightly more time that a car could sideswipe another. In either case, if it did occur, it would make for a relatively minor accident.
On the other hand, any additional speed, regardless what other cars are doing, will increase the risk of head-on and intersection collisions, which are both far more common and far more deadly when they occur. Matching the speed of other cars going your direction isn't likely to have any effect on the likely hood of, for example, someone turning left into your path.

For another thing the relationship between speed and stopping distance (just like with speed and air resistance) is non-linear - 2x speed = 4x the stopping distance.
Should an impact occur, the force of impact has the same relationship to speed.
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Quote:
Originally Posted by Piwoslaw View Post
A few months ago I returned home just as my neighbor pulled into his driveway. It was cold (around freezing) with some rain and sleet, and he yells to me: You rode your bike? In this weather?!?

So the other day we both returned home at the same time again, only now the weather is warm, sunny, with no wind. And I yell to him: You took the car? In this weather?!?
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