A quick look at some of the things that make transportation subsidization work (or not):
Transit subsidy: Difference between operating costs and passenger fare revenues
Range of rail transit operating cost subsidies in US: 29-89%
Average public transit operating costs per passenger mile for peak travel: 33-99 cents
Subsidies received by Amtrak passengers per trip: $57.04
Commercial air passengers: $6.35
Commercial bus passengers: $0.10
Subsidies per passenger mile for mass transit: $0.193
Average annual subsidy for mass transit between 2002-2009: $9.5 billion
Cost of GM bailout: $52 billion
Number of times more capital funding invested in highway subsidies than in public transit: 9
Cost of cumulative net subsidy of highway construction since 1947: $600 billion
Cost of killing Bin Laden since 2001: $1.27 trillion
Subsidies received by transit agencies from Highway Trust Fund: $10.7 billion
Percentage of Americans that would cut highway aid to balance federal budget: 12%
Percentage of Americans that would cut transit aid to balance federal budget: 27%