Ceres takes a step toward a new 99 interchange. The design might baffle you at first
Ceres is moving into detailed design for a new Highway 99 interchange near the south end of town.
The $133.5 million project would include a full interchange at Service Road, which now has a bridge across the highway but does not directly connect with it. The work also would involve upgrades to the current Mitchell Road interchange, about half a mile to the south.
The Stanislaus Council of Governments voted Wednesday, Jan. 15, to allot $6.59 million toward the design. StanCOG oversees transportation planning in the county.
The project could be done by 2027 if funding comes together, City Manager Toby Wells said last week. The city plans to pay for it with fees on developers, redevelopment money and Measure L, a countywide sales tax approved by voters in 2016.
The improvements would serve both Ceres and regional traffic, Wells said. This includes a Walmart Supercenter that could rise soon in south Ceres after years of delay. Mitchell Road is a major route for city residents and for big rigs to and from the Beard Industrial District, near Modesto’s southeast corner.
Unusual design
The Service Road interchange has a design — a “diverging diamond” — that’s new to California and possibly daunting to new users. Drivers on the new overcrossing would switch briefly to the other side as they approach the freeway ramps. Stoplights would keep oncoming traffic in check.
Caltrans is educating future drivers with a video simulation based on a diverging diamond in Utah.
California’s first diverging diamond is under construction just 20 miles away, on Highway 120 at Union Road in Manteca. It could be ready by year’s end.
Proponents say diverging diamonds have less potential for collisions than traditional interchanges.
They emerged in France in the 1970s and started appearing in 2009 in the United States, which now has 99, according to a website called divergingdiamond.com. The site was created by ATS/American, a transportation consultant based in Florida.
Wells said this design was one of more than 30 considered for Service Road. It turned out to be the only one “to handle the project traffic at the interchange over the next 20 years,” he said.
Reworking Mitchell
Mitchell would be converted to a partial interchange, with just a northbound offramp from 99 and a southbound onramp to 99. The bridge in this area would be replaced.
The project also would improve several city streets near 99 in south Ceres.
Wells said the detailed engineering will take until 2023, followed by construction between 2024 and 2027. The $133.5 million total includes $96.7 million in developer fees, $31.1 million from Measure L, and $5.7 million in redevelopment funds.
