FAIRFIELD — Motorists on the eastern end of Highway 12 through Jameson Canyon in Solano County are taking the high road.
As planned, the state Department of Transportation made the latest traffic switch on Thursday morning as it continues the multiple-year highway widening project. Vehicles headed both eastbound and westbound now travel on a half-mile section of new road along a terrace in the hillside.
Motorists seemed to take the change in stride. Past traffic switches on Highway 12 have had slight curves that seemed out of place, but not this time. Traffic flow seemed fairly natural.
The old section of road is 20 feet below the new one on the hillside at the farthest point. Now that it no longer handles traffic, construction crews can get busy there.
They will carve out a final section of hillside. They will build another retaining wall about 2,400 feet long. They will locate a 36-inch-wide Vallejo water line beneath the pavement of the old road. They will give the road a makeover.
Ultimately, both roadway sections will be used. The old road section will carry two lanes of eastbound traffic and the new road section will carry two lanes of westbound traffic.
Highway 12 through Jameson Canyon for decades has been a narrow, two-lane road for most of its 6-mile length. The $130 million Highway 12 widening project will create four lanes to carry an average of 32,000 vehicles daily between Interstate 80 in Solano County and Highway 29 in Napa County.
The Napa County side of the project looks all but done. Four lanes of paved road are in place for these 3 miles. But except for the eastbound mile between Highway 29 and the Chardonnay Golf Club, which has long been two lanes, temporary barriers continue to restrict motorists to one lane in each direction.
Caltrans Senior Resident Engineer Elias Moussa on Tuesday gave a tour of the project to media. He said the Napa County side still needs such work done as striping and signage. The four lanes could open along this 3-mile stretch in mid-February, he said.
Workers began the Highway 12 project in spring 2012. The Napa County side in recent weeks saw a flurry of paving activity that is now finished.
“Paving is the easiest part,” Moussa said.
The harder tasks are dealing with utilities, building in the drainage and creating the layers of roadbed, he said. He pointed to a 20-foot-tall concrete retaining wall holding back a hillside.
“A wall like this will take you three months to build,” Moussa said.
In short, it’s creating the footprint for the road that takes most of the work. Along one section of Highway 12, workers had to carve away a large section of a massive hill that blocked the new right of way.
Motorists, after putting up with traffic delays at various times over the past year, can see the outlines of the four-lane version of Highway 12 in place. Within a half-year, they might be able to use all of it. Moussa said the entire 6-mile-long construction project could be finished in as soon as August.
Putting in and establishing landscaping could take another year. But motorists will be able to watch that work from a four-lane Highway 12.
Reach Barry Eberling at 427-6929 or [email protected] Follow him on Twitter at www.twitter.com/beberlingdr.