For some reason, some of you have an illogical fear of cars behind you. Cars are behind you all the time! The likelihood of being whacked from behind by a car are infinitesimally small compared to other bike/car accident scenarios.
Roll up to the last car in the cue and wait your turn like everybody else. Nothing pisses drivers off more than having to pass a bike they just got done passing. Keep that up and you MAY have to start worrying about the drivers behind you...