The EPA alleges that the design of the VW device was to shut off emissions control devices except when the vehicle was undergoing any sort of emissions testing. According to the EPA “This results in cars that meet emissions standards in the laboratory or testing station, but during normal operation, emit nitrogen oxides, or NOx, at up to 40 times the standard.”

The State of California has issued its own notice of violation, and the EPA is working in conjunction with the Department of Justice and California on the investigation.