The Austin Road overcrossing — the biggest impediment to significantly improving traffic flow on the 120 Bypass  —  is proposed for replacement by Caltrans in a three-step undertaking to reduce back-ups and improve safety.
By replacing the overcrossing clearance would be made for an additional through southbound lane on Highway 99 to reduce congestion caused by a back-up of merging traffic on the 120 Bypass as far as three miles to the west of the Highway 99 interchange.
In the meantime, Caltrans has already made some minor improvements to signage on the approach to the pivotal interchange that connects Highway 99 — dubbed by some as California’s Main Street for the amount of agricultural and others goods it moves — and the 120 Bypass that ties it into Interstate 5 and the Bay Area via I-205 and I-580.
 Those signs advise eastbound 120 traffic to “stay in lane” as it nears the 99 connector, directing “trucks right lane only” on 99 north of the Yosemite Avenue interchange and an “end truck lane control” south of the Austin Rod interchange.
“It’s a Band-Aid solution but Caltrans is working with (local government) on long-term solutions,” noted Manteca Councilman Richard Silverman.
Silverman along with Mayor Steve DeBrum have taken the lead in coordinating a region wide effort to press for upgrades. Silverman noted the interchange is crucial to the region as well as reducing carnage on the 120 Bypass.
Next up on Caltrans’s list is the installation of an automated warning system that will include an interchangeable message sign, four traffic monitoring installations and camera on eastbound 120 to give real time information to drivers about back-ups. Construction is expected to start in October at a cost of $578,000.
Next month a “trucks right lane only” sign will be placed on the overcrossing connecting to the Bypass for southbound 99. That will cost $70,000.
Within the next three years the followings signs will be placed on existing overcrossings or sign trusses on eastbound 120 between Interstate 5 and 99.
“SR-99 exit 3 miles” at the Airport Way overcrossing.
“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno 2 miles” at the Union Road overcrossing.
“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno 1 mile” at the Main Street overcrossing.
“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno exit only” at the existing sign trusses just prior to Highway 99.
Two alternatives are being considered for the long-term improvement with the goal of starting work in the summer of 2021.
The first could cost as much as $40 million. It would widen the connector to southbound 99 to two lanes, construct braided ramps (that are physically separated from freeway lanes) at the Austin Road interchange and replace the Austin Road crossing to provide and additional southbound 99 through lane. In some instances braided ramps require constructing bridge structures to send traffic above other lanes.
The second would cost upwards of $29 million widen the connector to two lanes, permanently close Austin Road on and off ramps and replace the Austin Road overcrossing to provide an additional southbound 99 through lane.
The long-term project is proposed for funding with help from Measure K sales tax and savings from the Proposition 1B projects for Highway 99 improvements through the Central Valley as well as federal money. The funding has not been confirmed.
Silverman and the rest of the San Joaquin County One Voice effort last month pushed the need for funds for improvements for the interchange with federal officials noted it has a major impact not just on the region by the California economy.