National Parking Service

Washington, D.C., is cursed with some of the heaviest traffic and worst air pollution in the country. But the obvious solution -- reducing the number of drivers on the road -- faces a major obstacle: the federal government, which supplies free parking, thereby eliminating a major incentive to take public transportation. The federal government is the biggest employer in D.C. and owns some 38,000 parking spaces in the city and surrounding areas. It also pays for thousands more parking spaces, all at taxpayer expense. (The National Institutes of Health alone provides 8,844 free parking spaces on its main campus and spends about $6 million per year for 8,365 additional spaces at satellite sites.) Private companies have jumped on the parking-perk bandwagon as well; in all, 68 percent of D.C.-area commuters have free parking at work, according to a survey by the Metropolitan Washington Council of Governments. A separate survey, conducted by Metro, the region's public transportation agency, found that those with free parking were half as likely to take the subway or bus as those without. "If you're giving someone $200 a month [worth of free parking], talk about an incentive to drive your car," said Dan Tangherlini, acting director of the D.C. Department of Transportation.