[susi22]

You're right. But in case of a traffic jam we operate at speeds that allow us to do this. Look, the Article's author actually mentions it too:

Quote:

"The difference between these is negligible at high speeds, but at a low enough speed, it becomes difficult to maintain a 2 second following distance from the front bumper of the car in front of you without impinging on the rear bumper of the car in front of you, especially if said car is more than 0 feet long. So under these circumstances the flow rate of the highway decreases below 1 car every 2 seconds — maybe to 1 car every 5 seconds. So now you have to wait 5 seconds for every car in front of you in line."

There you have it. We have plenty of space/time to play with in case we're in a traffic jam since we approach very very slow speeds.

Obviously I'm not saying you should stay 10ft behind somebody when going 80mph.