[twoodfin]

But, trains involve a direct transaction that (partially) funds the facility in a user-pays way. Roads are funded by taxes. They try to use registration and petrol taxes that are related to use of roads but it's still a tax, not a normal transaction. If you drive on a private road, you still pay petrol tax and the taxes can't be tied to use of a specific road. I'd say that's market points to the trains.

Most U.S. public mass transit could not maintain itself based on "user pays", even forgetting about capital expenditures. Unsubsidized, fares would rise, ridership would fall, and prices would then need to be still higher to compensate.

On the other hand, the gas tax and other user fees (trucking, etc.) already fund the majority of U.S. highway spending both maintenance and capital (even with 1/6 of it redirected to mass transit!), and could easily fund all of it if the political will were there. Some people would drive less if we charged 2x the gas tax or had an odometer tax, but nobody thinks the system itself would be unsustainable in the same way that most public transit would be if it had to be funded entirely by its users.

[saosebastiao]

For every mile of interstate in the US, there are over 100 miles of local roads that are poorly covered by the gas tax. Paying for a majority of the highway system shouldnt be much harder than graduating from kindergarten. Its pretty pathetic that the entire highway system can't be funded by the gas tax, given how little it contributes to car oriented infrstructure. 2x gas taxes still wouldn't come close to covering the costs of the infrastructure provisioned. Gas taxes in the UK are 8x what we pay, and even that doesnt cover the full cost of their infrastructure. Transit, in comparison, is magnificently cost efficient...only by deceptive means like yours can you appear to make the opposite case.

Regardless, the effect of even a tiny subsidy for cars affects the cost recovery of transit. By subsidizing cars, you actually force larger subsidies for transit. The operating and maintenance costs of car use scale linearly with vehicle miles travelled, whereas the costs of transit scale as a step function (you don't need a new bus for every user, you need a new bus for every 60 users...riders 2 through 60 ride for free) on the scale of an individual transit vehicle, and roughly log linear in aggregate. Therefore, every transit user you subsidize into a car increases the per user cost of all the rest of the transit users. If car users paid even a tiny fraction more than the pittance they currently do, it could push enough users onto transit to make it sustainable. And if they acctually paid their true costs, almost nobody would drive at all.

[smutticus]

"Nationwide in 2011, highway user fees and user taxes made up just 50.4 percent of state and local expenses on roads. State and local governments spent $153.0 billion on highway, road, and street expenses but raised only $77.1 billion in user fees and user taxes ($12.7 billion in tolls and user fees, $41.2 billion in fuel taxes, and $23.2 billion in vehicle license taxes).[3] The rest was funded by $30 billion in general state and local revenues and $46 billion in federal aid (approximately $28 billion derived from the federal gasoline tax and $18 billion from general federal revenues or deficit financed)."

That a direct quote from here: http://taxfoundation.org/article/gasoline-taxes-and-user-fee...

Which cites its source as the, "U.S. Census Bureau, State and Local Government Finance 2011."

[twoodfin]

I was careful to say "highway system", by which I meant the IHS. Yes, local governments fund local roads out of property and other local taxes, but a) Everyone depends on their own local roads, even if they never drive, walk or bike on them, not so mass transit b) Local gas taxes are hard to make work because it's possible and tempting for gas stations to locate in the lowest taxed locality.

Even so, your own link says 50% of state and local roads are funded with user fees. The IHS number is around 70%, even with 1/6 of the gas tax redirected to public transit. If you doubled the user fees and eliminated all other sources of funding, the IHS and the state/local road system would still thrive. Not so most public transit.