This map contains state laws and regulations promoting the use of biofuels, including biodiesel and ethanol. The policies include the following:
Note that the policies highlighted here specifically promote the use of biofuels. Additional state policies that apply to all vehicles and alternative fuels, including biofuels, may not be included. Related state maps on our site include Plug-In Electric Vehicles and Low Carbon Fuel Standards .
Source: U.S. Department of Energy Alternative Fuels and Advanced Vehicles Data Center. The website contains a database for federal and state incentives and laws. Here is a link  to the search query for these results.