[78F350]

Here's the summary:

"In July 2015, the U.S. Environmental Protection Agency (EPA) introduced a proposal that would have prohibited the conversion of street vehicles into race cars used exclusively for the track. While the EPA has formally withdrawn the proposal, the agency continues to assert authority under the Clean Air Act to regulate the modification of vehicles used for competition. Congressional action is the only way to guarantee that street vehicles can continue to be modified for the track, well into the future.

The RPM Act confirms that it has always been Congress’ intent that racecars are not include in the Clean Air Act’s definition of “motor vehicle.” The RPM Act makes clear that it has always been legal to modify a street vehicle into a racecar used exclusively at the track, and confirms that modifying these vehicles for exclusive track use would not be considered tampering."