Following Distances

[kalvado]

In either case, I  don't quite understand how to measure distance to another car in car lengths. time is an easier metrics for me. 

You get really close, then have the passenger hook a tape measure onto the vehicle, then drop back until the tape measure reads an appropriate number, then get really close again to unhook the tape measure, then drop back again.

Photos or it didn't happen 

Of course it did!

[jakeroot]

^^
That first one is the "Full Audi" following distance.

I was driving in some quick-moving heavy traffic yesterday, and my following distance (along with others) was down to, "one mississi..." Might have been too close.

I hope that was not "one mississi... BOOM! OH SHIT!!!"

Hahaha could have been, had I not been paying attention!

[Sam]

The New York Thruway recommends three seconds, but it used to recommend a distance that corresponded to two-and-a-half seconds.

http://www.thruway.ny.gov/travelers/safety/drivingsafety.html

Don't Tailgate
It is dangerous to drive too closely to the vehicle ahead of you. To provide enough space between you and the vehicle ahead of you, use the "three-second rule." Choose an object near or above the road ahead, such as a sign, tree or overpass. As the vehicle ahead passes it, count aloud slowly: "One thousand one, one thousand two, one thousand three." If you reach the object before you finish counting, you are following too closely. When weather, driving conditions or visibility is poor, increase the count to four or five seconds to allow for more time.


From the 1969 New York Thruway Map: