Clean Cars Program


Since cars first hit America’s roads, the federal government has relied on states to regulate vehicle emissions, which for decades were creating some of the dirtiest air in the world, severely impacting public health and states’ economies.

In 1970, with the passage of the Clean Air Act (CAA), Congress directed the federal government to begin regulating motor vehicle emissions alongside California, which was home to the nation’s most deadly air pollution and had the longest history of setting its own motor vehicle standards. In recognition that states needed the freedom and ability to protect the public health of their own citizens, Congress used Section 177 of the CAA to explicitly grant states the right to either follow federal standards, or follow the standards set by California, which are stronger than federal standards.

Thirteen states—representing more than one-third of the new car market—decided to adopt the strong state standards. And in 2012, the federal government announced that California, federal agencies and automakers had agreed to adopt the National Program: nation-wide vehicle emissions standards that incorporated the states’ more stringent standards.

The Trump administration is now reneging on that deal, attempting to roll back the National Program despite overwhelming evidence that it is working effectively and should, if anything, be strengthened. In addition, the Administration has launched an attack on the long-held rights of states to protect their residents from vehicle pollution.

2018_177 States Graphic_v3_Horizontal-text2018_177 States Graphic_v3_Horizontal-states