[Spare_account]

The principle is sound, but the ants actually obey the rules whereas (in the UK at least) a small contingent of human drivers will ignore the limits, speeding up and slowing down between enforcement cameras. This concertina effect from just a small number of drivers is enough to slow the entire flow of traffic.

[lotsofpulp]

It would have happened anyway after a certain density of vehicles is exceeded, since each car and truck had different accel/decel rates. Especially if there is an incline anywhere.