DETROIT — The U.S. Environmental Protection Agency plans sweeping changes to the way it tests for diesel emissions after getting duped by clandestine software in Volkswagen cars for seven years.

Chris Grundler, head of the EPA’s office of transportation and air quality, indicated the agency would add on-road testing to its regimen. VW’s sophisticated software allowed its cars to pass tests in the lab and then spew pollution while on the highway.

The EPA’s testing procedures have been criticized for being predictable and outdated, making it relatively easy for VW to cheat. What’s more, the EPA did not initially uncover the problem; researchers at West Virginia University did, using on-road testing.

Grundler says the changes are designed to detect software and other methods automakers might use to rig a test.

The EPA and the California Air Resources Board have engineers who are “developing clever ways in which these things can be detected,” he said.

He also notes that testing of diesel engines, which make up only 1 percent of the vehicles on U.S. roads, wasn’t the top priority for the EPA. The agency did have on-road testing equipment — but it was assigned to monitor automaker gas mileage estimates and heavy-duty diesel trucks, where cheating had been uncovered in the past.

VW has admitted to installing software on Volkswagen and Audi cars with four-cylinder diesel engines that switches on pollution controls when they are being tested. When the software, called a “defeat device,” determines that the cars are back on real roads, the controls are turned off. The EPA says about 500,000 U.S. cars including the Jetta, Golf, Beetle, Passat and Audi A3 have the cheating software, and VW says a total of 11 million cars have it worldwide.

VW was able to fool the EPA because the agency only tested the cars on treadmill-like devices.