"Many suburbanites take free parking for granted, whether it's in the lot of a big-box store or at home in the driveway. Yet the presence of so many parking spaces is an artifact of regulation and serves as a powerful subsidy to cars and car trips. Legally mandated parking lowers the market price of parking spaces, often to zero. Zoning and development restrictions often require a large number of parking spaces attached to a store or a smaller number of spaces attached to a house or apartment block.
If developers were allowed to face directly the high land costs of providing so much parking, the number of spaces would be a result of a careful economic calculation rather than a matter of satisfying a legal requirement. Parking would be scarcer, and more likely to have a price - or a higher one than it does now - and people would be more careful about when and where they drove."
Writer and economics professor Tyler Cowen argues that cities need to bring the full costs of automobile transportation into their policies, starting with parking.