I tried doing a google search and came up empty. What is the distance of "a car length"? 15 feet? 20 feet? 25 feet? 30 feet? When driving behind someone (say on the freeway), I tend to stay 2 seconds (or more) behind them. Say at 60 mph (88 feet/second) this is 176 feet. Some would say keep 6 car lengths behind someone when driving 60 mph. But how long is that? Weigh in!
Here is one answer obtained via Google. I don't think there is an "official" definition: WikiAnswers - What is the average length of a car
The two second rule is much easier to follow, even if you knew how much a car length was. It works at any speed, except in urban traffic where it's almost safer to tailgate than be cut off.
Here's an interesting tidbit I found http://www.dmv.ca.gov/pubs/curriculum/Unit 7.pdf Page 6 - rules of the road - tailgating - they want you to stay back 3 seconds. Good God! That means I'm tailgating for a decent proportion of my driving day. Ugh.
Very few private passenger cars were ever 20 feet long. The average back in the olden daze when the 1 car length per 10mph rule was drivers ed wisdom was about 15 feet. That is essentially 1 second which isn't enough unless you are really on top of your game. 2 seconds is the closest you should follow if traffic allows it. If you are following at 2 seconds and people keep cutting in front of you, then you might consider one second. 3 seconds is better but not realistic except on the open road.
@xs650 +1 That was what I had figured out too ... the old 1 car length per 10 mph rule is roughly the equivalent of the 1 second rule.
