Dollars & sense 
Walking costs cities very little, unlike driving and even public transit. A resident’s bus ride may cost $1, but costs the city $1.50 in bus operation. If a resident decides to drive, it costs the city $9.20 in services like policing and ambulances. When a resident walks, the cost to the city is a penny. — Jeff Speck, Walkability City Rules: 101 Steps to Making Better Places

Gas taxes and other fees paid by drivers cover less than half of road construction and maintenance costs nationally. Regardless of the amount driven, the average American household bears a burden of over $1,100 annually in taxes and indirect costs from driving, over and above gas taxes or other driving fees paid.
— MassPIRG/Frontier Group, Who Pays for Roads?