On April 10, University of Illinois economics professors Scott Irwin and Darrel Good recommended freezing the Renewable Fuel Standard (RFS) mandate for 2014 and 2015 at 2013 levels. Writing in the University of Illinois’s agriculture publication Farmdoc Daily, the pair said the freeze would fuel the ethanol market, ensure investments in infrastructure to allow for better widespread adoption of ethanol and give lawmakers time to improve biofuels policy. While 15 percent ethanol (E15) has been approved by the Environmental Protection Agency (EPA) for cars made in model years 2001 and beyond, only a few gas stations are selling this fuel. The RFS mandate is 13.8 billion gallons of ethanol blended with gasoline in 2013, 18.15 billion gallons in 2014, and 20.5 billion gallons in 2015.