A Sacramento judge is sending the California Department of Transportation back to the drawing board over its controversial plan to widen and straighten Highway 16 in the rural Capay Valley.

"It's an enormous win for the community," said Tom Frederick, a local winery owner and member of the Capay Valley Coalition.

The group and the Yolo County Farm Bureau sued Caltrans last year over its State Route 16 Safety Improvement Project.

Thousands of motorists drive the winding highway each day on their way to the Cache Creek Casino Resort.

Caltrans contends the narrow, twisting road is a danger and needs major upgrades to prevent accidents and ease emergency response.

The department also wants to raise low-lying sections of roadway prone to flooding.

The changes would affect an approximately 12-mile stretch of highway between Interstate 505, near Madison, and the casino, near Brooks.

Residents and farmers argue the project would destroy farmland and damage the valley's rural character. They say accidents have decreased in recent years and insist small-scale changes will help.

They filed a lawsuit in January 2010 challenging Caltrans' December 2009 final environmental impact report on the Highway 16 project.

Sacramento Superior Court Judge Michael Kenny sided partly with the residents in a 42-page ruling issued late last week.

Kenny wrote that Caltrans had failed to provide sufficient accident data, including a breakdown of collisions by location, to show a need for the project.

He also said the department had failed to adequately weigh options, such as the "spot improvements" and narrower shoulders favored by some residents.

Caltrans officials "prejudicially abused their discretion in failing to consider a reasonable range of feasible alternatives as required by (the California Environmental Quality Act)," the judge wrote.

Caltrans did not adequately address the project's impacts on agriculture or respond to public comments, he wrote.

The judge said he would draft an order for Caltrans to rescind its approval of the project.

Don Mooney, a lawyer who represented the coalition, said he hoped Caltrans would draft a revised report with more detailed data.

"What it really comes down to is providing the information to the public," Mooney said.

Caltrans spokesman Mark Dinger said the department still plans to go forward with the project.

Department officials are reviewing the judge's ruling and "looking at ways to comply with his order," Dinger said.

That will require rewriting the environmental impact report and giving the public time to review it, he said.

The department had hoped to advertise for construction bids later this year, he said.

"That doesn't seem likely to happen," Dinger said. "This could push it out for another year."

© Copyright The Sacramento Bee. All rights reserved.

Call The Bee's Hudson Sangree, (916) 321-1191.

• Read more articles by Hudson Sangree