Major detour begins for upgrading Highway 99/120 interchange in Manteca. When and where?
The Austin Road bridge over Highway 99 will be demolished soon as part of upgrades to the Highway 120 junction to the north.
The bridge will be replaced over about 18 months, the San Joaquin Council of Governments said in a email alert. The closure was to begin Tuesday, Feb. 18, after a rain delay of several days.
The overall $48.2 million project also will provide a second lane where eastbound 120 connects with southbound 99 in Manteca. This is a tight spot now for drivers from Stanislaus County and points south, many of them returning from Bay Area jobs.
The Austin Road bridge is part of a separate Highway 99 interchange in south Manteca. Detours will involve Moffat Boulevard, Spreckels Avenue and Yosemite Avenue.
The project also will require much shorter closures of some of the current 99-120 ramps. Drivers can check for updates on the SJCOG website.
Construction began in August by Teichert Inc. of Pleasanton and is expected to take two years. It will add a fourth lane on southbound 99 between 120 and Austin. This local road will get new connections to Atherton Drive and Woodward Avenue.
The new Austin Road bridge also will cross the freight tracks along 99, a safety hazard for drivers. The tracks will be part of the expanded Altamont Corridor Express, which now takes passengers between Stockton and San Jose. The first trains to Modesto and Ceres could run as soon as late next year.
SJCOG is funding the highway work with the county’s Measure K sales tax, fees on property developers and state and federal sources.
This is the first phase of the long-term plan for the 99-120 junction. The second phase could cost about $28 million and open by 2033, according to the California Department of Transportation. It projects a $62 million cost and 2042 opening for the third phase. No funding is in hand for the work.
This story was originally published February 18, 2025 at 12:44 PM.
