@parados,
Here is an interesting table from the following website, indicating that mass transit is one of the most inefficient methods of transporting people, buses consuming 4,235 BTUs per passenger mile. In contrast, cars consume 3,512 BTUs and more efficient hybrid cars only consume 1,659 BTUs. Also, according to the table, buses only carry 8.8 passengers on average. It would be common sense to assume that figure might be far less in some cities.
The data supports what I have said, that mass transit's supposed efficiency is often a myth.
http://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation
Transport mode Average passengers
per vehicle BTU per passenger-mile MJ per passenger-kilometre
Vanpool 6.1 1,322 0.867
Efficient Hybrid 1.57 1,659 1.088
Motorcycles 1.2 1, 855 1.216
Rail (Intercity Amtrak) 20.5 2,650 1.737
Rail (Transit Light & Heavy) 22.5 2,784 1.825
Rail (Commuter) 31.3 2,996 1.964
Air 96.2 3,261 2.138
Cars 1.57 3,512 2.302
Personal Trucks 1.72 3,944 2.586
Buses (Transit) 8.8 4,235 2.776