Automobile driving in the United States is subsidized.
The remainder is paid by all taxpayers through local, state, and federal taxes, whether we drive or not. Because bicycling puts so little wear and tear on our roads, and because cycling-specific infrastructure is far cheaper than general road costs, a cyclist who never buys gasoline easily pays his or her fair share. Add to this denied bridge access, and general taxation for environmental damage caused by cars and defense payments to support our oil interests abroad, it's clear that it's not bicyclists who are getting a free ride.