An explicit environmental action?

I noticed everytime a bus in Kyoto stops for more than a few seconds, the engine automatically shuts down. Initially I thought it was just an old dodgy bus (the first day I arrived) but every bus does it. I wonder if this is done on purpose to cut down on fuel consumption and CO2 emissions? Does it take more fuel to restart or stay idle for 30 seconds? Any of you petrolheads can answer that?

I also wonder if this has something to do with the fact that the International Framework Convention on Climate Change (the Kyoto Protocol) was created here? (setting a good example)

chet (who can't sleep despite tomorrow being a long day trip to Nara)