Public transportation is wonderful - saves gas, reduces traffic, saves money, etc.. On the other hand, buses stop frequently, which means all of the cars behind them must stop, too - and if it's a school bus, traffic in both directions stops. And since the stop/start/stop/start cycle is what makes city driving so much less efficient than highway driving, I wonder how much extra gas is burned due to the need to stop - and then start - behind city buses. I'm sure someone has done this math.