Use of public transportation in the D.C. metro area saves 245 million gallons of oil a year and more than $640 million in gas, according to a study released Friday that promotes taxpayer investment in transit.

The report from U.S. PIRG, the federation of state Public Interest Research Groups, concludes that America‘s “automobile-centered transportation system” is “increasingly out of step with the challenges of the 21st century.” Projects such as the proposed Metrorail connection to Washington Dulles International Airport demand federal investment, the study’s author said, while transit nationally must become a higher priority in future transportation funding authorizations.