For buses in particular, bear in mind that liquid fuels typically require pumping, which usually uses electricity. So gasoline or diesel pumps might not be available, even if the underground storage tank has fuel. Here in California, a lot of public buses are fueled with Compressed Natural Gas (CNG) which in theory could have already been compressed at the depot, but this would only last so long, since it takes energy to run the compressor, assuming the natural gas pipeline is unaffected.

Obviously, electric buses and trolleybuses need electricity. So at this point, perhaps the only bus that would be totally immune is an omnibus, that 19th century people-mover that was drawn by horses. But consider the “emissions” from a horse though…

In all seriousness, the contingency plans for a transit agency will vary depending on where you are in the world. For American transit agencies, most don’t even offer service on Sunday or holidays (very strange in the land of hyper religiousness; no bus to church??) and any labor strikes usually result in every service being closed, sometimes including essential ADA operations.