VW admits thwarting pollution control for years

Volkswagen became the world's top-selling car maker trumpeting the environmental friendliness, fuel efficiency and high performance of diesel-powered vehicles that met America's tough Clean Air laws.

VW's success story was so good that pollution-control advocates did their own tests, hoping to persuade other countries to enforce the same strict standards.

Instead, they got a foul-smelling surprise: In actual driving, the VWs spewed as much as 40 times more pollution from tailpipes than allowed by the U.S. Environmental Protection Agency.

"We ran the program to show that U.S. diesels are clean," said John German, senior fellow with the International Council on Clean Transportation, the group that blew the whistle on Volkswagen. "Turned out we found a violator."

The EPA and the California Air Resources Board announced the violations on Friday, accusing VW of installing software that switches on pollution controls during smog tests, then switches them off again so that drivers can enjoy more engine power on the road.