Caltrans contract worker José Bobadilla stood on unshaded asphalt Tuesday afternoon in heat warmer than 90 degrees southeast of Chinese Camp to stop motorists headed farther east up to Groveland and Yosemite.

One-way traffic controls went into effect Tuesday for the $20.8 million project to upgrade James E. Roberts Memorial Bridge on State Route 120 in Tuolumne County, and the traffic controls are expected to remain in place for the duration of the project. Completion is hoped for by Thanksgiving 2017, according to the state Department of Transportation.

Bobadilla used a two-way sign that says “STOP” on one side and “SLOW” on the other. Sometimes 50 or more vehicles backed up westbound from Bobadilla’s station.

Delays lasted between 5 minutes and 25 minutes, depending on work activity on the bridge.

Bobadilla was one of several people at work Tuesday to get the upgrade project going. Some workers helped unload concrete sections of K-rail off the back of big-rig trailers. The barriers were put in place to set aside a safe work zone on the bridge, said Saeid Mehrtash, a Caltrans field resident engineer.

Motorists headed in both directions on Highway 120 can expect delays before crossing Roberts Bridge, said Caltrans District 10 spokesman Rick Estrada.

Temporary traffic signals have been set up on both ends of the bridge, but they were not working Tuesday. Bobadilla monitored the west end of the bridge, and his co-worker Gustavo Cobian guided motorists at the east end.

Some eastbound motorists who had to wait were driving campers or pickups hauling boats on trailers. Several westbound truckers who waited were hauling fresh-cut logs out of the Stanislaus National Forest and other timber harvest areas.

Upgrades

Primary goals of the Highway 120/James E. Roberts Memorial Bridge project are to replace the bridge deck and retrofit the structure for 40 more years of service, according to Caltrans.

The 46-year-old bridge is considered safe, said Rick Estrada, of Caltrans District 10. It was built in 1970 and opened in 1971, the same year New Don Pedro Dam was completed and Don Pedro Reservoir was expanded to submerge more than 25 miles of the Tuolumne River when full.

It was first named the Tuolumne River Bridge and was renamed Roberts Memorial Bridge in 2007 to honor a deceased bridge engineer who was considered a leader in seismic retrofitting.

The bridge is 1,400 feet long and spans a former section of the Tuolumne River that is flooded out by Don Pedro Reservoir.

Nighttime closures are expected to begin in October. The Highway 120 route is normally one of the most popular gateways to Yosemite National Park. It’s also a lifeline connector between Sonora, Jamestown, Chinese Camp and Groveland.

Caltrans recommends detours on Jacksonville Road as well as La Grange Road, Bonds Flat Road and Highway 132.

Jacksonville Road

The Jacksonville Road detour is the existing shortcut between Jamestown and Moccasin. For residents of Sonora, this is already the fastest way to drive up to Groveland.

Some residents in the Stent-Quartz area outside Jamestown are unhappy about having more traffic come through their rural neighborhood. The roads are narrow, and there are already enough speeding motorcycles, cars and smaller trucks coming through.

Jacksonville Road and the rest of the detour recommended by Caltrans is all on public, paved roads. Trucks with more than four axles, or with a registered gross vehicle weight of 80,000 pounds or more, are prohibited on the route, Caltrans District 10 officials say.

Large big rigs with more than four axles and exceeding 80,000 pounds gross weight will have to use the longer detour combining La Grange Road, Bonds Flat Road and Highway 132.

La Grange-Bonds Flat-132

The La Grange-Bonds Flat-132 detour, all on public, paved roads, may benefit businesses near Lake Don Pedro, Coulterville and Big Oak Flat, depending on how many motorists and truckers decide to use it.

This route may also appeal to travelers coming from Modesto, Turlock and Merced, especially if Highway 140 is busy or closed due to rockslide, flooding or fire.

There is already a single-lane bridge on Highway 140 below El Portal due to Ferguson rockslide activity that began in April 2006. The current fix includes traffic signals at each end of the temporary bridge and delays for motorists heading to Yosemite. Caltrans hopes for a final fix in the Ferguson slide area by summer 2020.

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