The Environmental Protection Agency is reportedly preparing to require all automakers to verify fuel-efficiency estimates via new real-world driving tests.
The move is said to be focused on preventing automakers from using computer modeling or lab-test manipulation to exaggerate fuel economy claims. The agency has received complaints from many drivers who achieve real-world mpg figures that are significantly lower than manufacturer claims.
Several automakers have been forced to revise their mpg ratings for existing models. Notable cases include a handful of newer models from Hyundai, Kia and Ford.
“Some auto makers already do real-world verification, but we are establishing a regulatory requirement for all auto makers,” EPA Office of Transportation and Air Quality director Chris Grundler told The Wall Street Journal.
The greatest discrepancies between fuel economy estimates and real-world performance have appeared in hybrid models. Ford’s 2013-2014 Lincoln MKZ Hybrid is a glaring example, with a recent revision dropping its city/highway mpg estimates by 7-8 mpg.
Ford blamed its error on incorrect rolling-resistance figures that were correlated to wind tunnel observations when determining MPG estimates. The EPA proposal aims to force companies to compare their computer-modeled variables against observations from real world testing on a track, verifying figures for wind resistance and rolling friction.
The EPA is preparing to accept public comments on the proposal before moving forward with implementation.