Any extra space you leave between you and the car in front of you is artificial traffic you're creating. That's space that could be used by more cars. Ideally,

Any extra space you leave between you and the car in front of you is artificial traffic you're creating. That's space that could be used by more cars. Ideally, at a traffic stop every car would sit literally bumper-to-bumper to maximize throughput but that's obviously not reasonable. You can see clearly from the simulation that having the opportunity to move around an obstruction doesn't stop the ensuing slow down from occurring because you have to slow down and reduce the bandwidth of the road to move around the obstruction.