Tourer
Posts: 447
Cleveland, GA | Okay... While I agree with the spirit of her comments in the video, she is flat wrong on the numbers. I'm not slamming her or the video, and I'm not trying to be a horse's butt here. I just wish she had gotten the numbers right.
She said in the city, 2-4 car lengths or 2-4 seconds, and on the highway 6 car lengths or 6 seconds. Conventional wisdom used to be one car length for every 10 mph. With a 20-foot car, six car lengths would be 120 feet at 60 mph.
The car-lengths formula has given way to the rule of thumb of a two-second following distance, as it is easier to figure. The faster you are traveling, the farther you are apart for each second. At 60 mph a car is travelling 88 feet per second, so two seconds distance would be 176 feet following distance; reasonably close to the car-length formula. But she said 6 seconds - which would be 528 feet... nearly 1/10th of a mile.
Um... no.
While it would be admirable to attempt this, it is in no way feasible - too many people would fill the gap. Shoot, it's hard enough to keep a 2-second distance in any kind of traffic at all!
As an MSF instructor, I teach a 2-second following distance (or more, depending on conditions). She's way off base here, and to me, has no credibility by using those numbers. Just my opinion and my two cents worth.
As I said, I agree with the spirit of this - I try to always keep a good separation in traffic. Distance buys you time to maneuver when it comes to staying out of trouble on the road.
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Speed and space management.
