Interesting article, needs more research in order to make a more complete analysis.

http://www.bbc.co.uk/blogs/ethicalman/2009/11/why_cars_are_greener_than_buses.html

It does indeed merit further examination G :y

I used to drive the local rural bus service and can categorically state that if all of the (few) passengers had switched to taxis (excepting the am/pm school run) the CO2 saving would have been immense-plus an enormous saving financially for the council who subsidise these services massively.

Don't forget aswell that buses need starting an hour or two before use in cold weather to be able to see out of the window-drivers will sit revving the nuts of it to get heating to work as engine is at the back and the heating pipes run 10m+ to the front.  Then there is loads of wasted/dead mileage when changing routes or running out of service, plus engines are left running on breaks or while it is being cleaned or sanitised and some drivers will run late to increase breaks and then hoof it to catch up-it's not their diesel they waste.

I have worked for 5 operators of coaches/buses and none would ever dare mentioning driving frugally or switching it off due to unions hitting back.  A simple water system pre-heater (like a Kenlowe hot-start) or aux heater fitted to each and every bus would be a start...

I spent 8 out of 9 hours running empty or with only two/three passengers on, on a full size single decker.
Many rural services could be replaced by a "points for taxis" system where the bus subsidy money was spent on providing a smart card for taxis on an assessed need basis-the OAPs would be savvy enough to then buddy up and share taxis to save points as it would be in their interest.  Not rocket science and would save a fortune in rural areas-and be more convenient for users :-/

In towns, full buses will always be more ecologically sound than cars, though.

dont know about the town side of this but most of the 100s i see running about our town through the day are empty or causing congestion as they sit in groups at the kerbs of our narrow side streets.most are too large for the turnings they go down :-/ >:(