Caltrans has settled a 14-year-old lawsuit with two environmental groups over polluted runoff that flows from state roads into the ocean.

Under the agreement announced Friday, the state Department of Transportation agreed to reduce runoff from freeways in Los Angeles and Ventura counties by 20 percent when compared with 1994 levels.

Agreeing to a specific figure is groundbreaking in environmental litigation, said David Beckman, director of the Coastal Water Quality Project for the Natural Resources Defense Council, one of two plaintiffs in the case.

Controlling toxic runoff is one of the few areas of environmental law that does not have quantifiable standards, Beckman said.

"Not only are we going to keep 6,000 pounds of pollution out of Ventura and Los Angeles County waters, but this agreement hopefully blazes a path that others will follow," Beckman said Friday.

Douglas Failing, director of the California Department of Transportation's District 7, which includes Ventura and Los Angeles counties, was traveling Friday and unavailable for comment.

In a media statement, Failing said, "This settlement isn't really a change in what we were trying to accomplish statewide. It is something we have been trying to achieve all along. What is important is that a methodology has been identified that we feel will work in this urban area of Los Angeles."

The Defense Council and Santa Monica Baykeeper filed the suit in 1994. The suit charged Caltrans with failing to enforce the federal Clean Water Act by not reducing runoff from roads. Polluted storm runoff — a toxic brew of motor grease, pesticides and other compounds — doesn't penetrate asphalt surfaces like those on freeways, parking lots and sidewalks. Most of it instead drains to the ocean.

On average, more than 6 million gallons of oil run into California's waters from roads and sidewalks, environmentalists say.

A federal judge ruled in favor of the two environmental groups in 1994, Beckman said. However, Caltrans dragged the matter on for years with legal challenges, he said.

The agreement to resolve the matter "is forward thinking and I hope a turn of the page," Beckman said of Caltrans. "But it's taken them a long time to move from a position of strident opposition to meeting their Clean Water Act opportunities to (making) it part of their basic standard operating procedure."

Under the agreement, Caltrans will use sand traps, catch basins and new types of porous pavement that traps polluted runoff and absorbs contaminants.

The Resources Defense Council will identify specific watersheds in both counties where cleanup work will take place. Caltrans will then examine about 1,000 miles of freeway in those watersheds. The agency also must submit pollution-reduction plans for each watershed by 2011. The cost of the work is unclear.

Paul Jenkin, environmental director of the Surfrider Foundation's Ventura County chapter, called the settlement good news.

"I hope it not only sets the stage for Caltrans improvements but for our local agencies to recognize this as a significant problem," Jenkin said of urban runoff.