I do understand it takes effort to stop and re-accelerate, but isn't making effort (exercise) part of the purpose of cycling in the first place? My main objection is to cyclist failing to stop at pedestrian crossing lights: as a pedestrian, when I see a green light, I expect to cross without having to dodge moving vehicles on the road. I do check the the road to make sure that cars have stopped, but cyclists (who rarely stop at crossings, at least in London) are harder to see, as they are smaller and often obscured by the traffic.