California air pollution regulators Thursday adopted a voluntary plan they say will speed cleanup of illegal diesel engines.
The plan gives diesel engine manufacturers four years to gradually remove devices that bypass emissions equipment in trucks, buses and recreational vehicles at highway speeds.
That´s drawing criticism from environmental groups because it applies only to about 60,000 California-licensed vehicles — but not the 300,000 out-of-state vehicles that sometimes use state highways.
The Air Resources Board says removing the devices from state-licensed vehicles will prevent 30 tons of diesel pollution from entering the atmosphere each day.
That´s the equivalent of removing a million cars from California highways.