Originally Posted by tandempower

Of course it is more sustainable, if it replaces flying and driving. Buses are more efficient than cars and planes, but they still have tires and thus more rolling resistance than trains.

The only reason buses are a better option than trains at this point is because they can use existing highways instead of building new rail corridors, which shouldn't be built through undeveloped land anyway, for environmental reasons.

Being able to link multiple buses without space in between them would greatly reduce wind drag, as it does with trains. In fact, I'm surprised Greyhound or some other long-distance bus operator hasn't come up with a system for connecting several buses in sequence with all the brakes connected on the same circuit they way a trailer's brakes are connected to the brake pedal of the truck towing the trailer.

Trains are the most efficient form of transportation, but for transitioning away from flying/driving in a society built around flying/driving, it makes more sense to put more people in buses and thus reduce congestion on highways rather than try to get rail corridors built that will only end up stimulating the automotive economy and that will get cancelled before they have a chance to actually divert any of that drive/fly traffic from the highways and skies.