Cost soars to redo Highway 99 interchange in south Ceres. Here is Plan B and a timeline
The design for a new Highway 99 interchange in south Ceres is being rethought.
That plan mainly involves adding ramps to the Service Road bridge, which now crosses the freeway without a direct connection. The current Mitchell Road junction just to the south would become a secondary link to this fast-growing business district.
The project cost was estimated at $120 million to $135 million in 2017, just within the expected funding. A recent review suggests that it could approach $300 million by the time it is built, City Engineer Michael Beltran told the City Council on Nov. 12.
Beltran said a key cost driver was the plan to shift that part of 99 about 80 feet to the east. That would require major detours on the six-lane state highway.
“It’s just becomes a project that is really too big,” Beltran said.
The council took no action. It could vote early next year on hiring consultants to do a detailed redesign and study of its environmental impacts. That could cost $5 million to $6 million and take up to 18 months, Beltran said.
The revised project would widen the Service Road bridge without shifting the freeway lanes. Four new ramps would be built next to 99 to take drivers in various directions.
“We’re not moving the mainline,” Beltran said. “The freeway stays exactly where it is.”
City officials had said in 2020 that the initial project could open to traffic by 2027. The target now is 2032.
Mitchell Road serves industrial zone, too
Ceres has freeway interchanges at Hatch Road, Whitmore Avenue, Fourth Street and Mitchell. The last one serves the Walmart Supercenter and other businesses nearby. Mitchell also is a key truck route to the Beard Industrial District near Modesto. It becomes El Vista Avenue and then Oakdale Road on its way to Riverbank.
The Mitchell interchange has a cramped layout that slows traffic at busy times. Service Road crosses 99 half a mile to the north and meets Mitchell in the heart of Ceres’ new growth area.
The city plans to pay for the new interchange with about $97 million in fees on land developers, $31 million from the Measure L sales tax for Stanislaus County, and $6 million from a past redevelopment program. State and federal grants also could be sought.
Beltran said the initial plan could cost $220 million to $250 million in current dollars and close to $300 million by the projected opening date. General inflation, which spiked in 2022, contributed to the rise.
Plan included ‘diverging diamond’ design
The rethinking means Ceres will not be using a “diverging diamond” design for the Service Road ramps. Drivers would have briefly crossed to the opposite site of the bridge before turning toward their destinations.
Diverging diamonds might look daunting, but supporters around the world say they reduce the number of conflict points among vehicles.
California got its first one on Highway 120 at Union Road in Manteca in 2020. The second will open on Highway 37 in Vallejo late next year, the San Francisco Chronicle reported.
The Bee story about the Manteca diamond included an instructional video from the Utah Department of Transportation.
This story was originally published November 29, 2024 at 12:00 PM.
