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Woodward being widened to four lanes from Moffat to Atherton Drive
99 work map
This map shows the work in phase one of the Highway 99/120 Bypass project that breaks ground this summer.

The groundbreaking July 17 on the first phase of the 120 Bypass/Highway 99 interchange means there will also be significant surface street improvements.

They include:

*A new alignment of Woodward Avenue to Moffat Boulevard that will be four lanes wide.

*The realigned Woodward Avenue will intersect with Moffat at a 90 degree angle with a railroad crossing similar to what is now in place at Industrial Park Drive.

*Traffic signals will be installed at Moffat and Woodward.

*Atherton Drive will be widened to a point just north of Valor Drive.

*A new connector street between Atherton Drive at a point north of Valor Drive will be constructed to Austin Road.

*Austin Road will be widened to four lanes to the south to the future point where Valor Drive will eventually be extended westward.

The freeway work includes:

*increasing the eastbound 120 Bypass transition ramp to southbound Highway 99 from one to two lanes,

*Temporarily removing the Austin Road overcrossing and replace it with a new four-lane structure spanning both Highway 99 and the Union Pacific Railroad.

* Modifying the existing northbound Austin Road exit ramp to conform to the higher overcrossing profile grade.

 *Closing the Austin Road northbound entrance and southbound exit ramps until future phases of construction.

 “This project is absolutely necessary to the region to improve traffic safety, reduce traffic congestion, and simply make the entire State Route 99 and 120 interchange better for everyone,” Escalon Mayor and San Joaquin Council of Governments Board Chair David Bellinger said.

 “It’s a vital transportation hub to move people safely and get San Joaquin County goods to markets outside the region. San Joaquin County is a supercommuter region and these improvements will bring far-reaching positive effects to all residents and commerce.”

The SJCOG board has awarded a $48.2 million contract to Teichert Construction to build the first phase.

Work will start this summer.

It is expected to be completed by early 2026.

“I’m so happy to be finally at this point on this project,” Manteca Mayor and SJCOG Board member Gary Singh said. “It’s been a long time coming. I’m really looking forward to breaking ground.”

 The three-phase project will be the first time ever that SJCOG is leading  a freeway construction project while coordinating with Caltrans, the City of Manteca and Union Pacific Railroad.

Long-serving board members have worked for years advocating for federal funding to match local Measure K funds for the project.

Measure K is the half-cent countywide sales tax that has been a catalyst for securing additional funds for road and transit projects such as the most recent widening projects for Interstate 205 and the 120 Bypass, the McKinley interchange, and ACE trains service.

“This is something we’ve all been working on for years,” San Joaquin County Supervisor and SJCOG board member Robert Rickman said before the board unanimously approved the contract award. “It’s another example of using Measure K funds, our tax dollars at work. … Once the project is finished, I think people are going to be very, very pleased.”

Other funding sources include State Transportation Improvement Program, Caltrans’ State Highway Operation and Protection Program, federal COVID-19 relief money, and the federal Highway Infrastructure Program.

The project will have a significant regional impact by improving safety and reducing congestion at a major highway interchange moving people and goods throughout the Northern California Megaregion

The second phase, that SJACOG is now working at securing money for  will add an additional transition lane from northbound Highway 99 to the westbound 120 Bypass.

The third phase will include six lanes from Airport Way to Highway 99.

Originally, it was going to be six lanes from Main Street to Highway 99 with the other two miles being widened from four to six lanes in a later project.

The third phase costing $55 million would:

*restore the southbound off ramp by constructing a grade-separated braided ramp to eliminate weaving with 120 Bypass merging traffic.

*construct the entrance ramp from Austin Road to northbound Highway 99 and to the westbound 120 Bypass as a braided ramp that will separate traffic movements to Highway 99 and the 120 Bypass.

*relocate the northbound Highway 99 exit ramp to Austin Road to accommodate the braided onramp.

*relocate the Highway 99 frontage road for about 0.8 miles.

*add an auxiliary lane in each direction on Highway 99 from the 120 Bypass to about 1.7 miles south of Austin Road by shifting the median away from the Union Pacific right-of-way and relocating the frontage road.

*add an auxiliary lane in the existing median of the eastbound 120 Bypass from Main Street to Highway 99 to provide a dedicated lane to connect to the new 120/99 separation structure.

The high cost of the third phase design is reflected in the necessity not to impede traffic flow and create a major safety hazard from the 120 Bypass south to 99 and from 99 going north to the eastbound 120 Bypass.


To contact Dennis Wyatt, email