Depends on the type of traffic. You're describing gridlock, but temporary jams are more common on freeways. In those situations, if everyone left extra followin

Depends on the type of traffic. You're describing gridlock, but temporary jams are more common on freeways. In those situations, if everyone left extra following space, it'd actually improve the overall throughput since people take extra time to stop then start. In some places, the police or automatic signs will even tell people to slow down in advance when there's a jam ahead.