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Includes widening Bypass to 6 lanes by 2030

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The 120 Bypass looking east from the Main Street overcrossing. The half cent Measure K sales tax will help fund $171.8 million worth of work addressing the 99/120/Austin Road interchange and wideni...

Bulletin file photo/

POSTED March 14, 2018 1:05 a.m.

Widening the 120 Bypass from Main Street to Interstate 5 from four to six lanes could be completed by 2030.
It is part of $1.1 billion in mainline highway improvement the San Joaquin Council of Governments is targeting for the South County to ease freeway congestion over the next 22 years. The projects are part of $11.5 billion in transportation initiatives planned through 2042 throughout San Joaquin County that are being leveraged with the half cent Measure K countywide sales tax. The sales tax — that allowed San Joaquin County to snag matching state bond funding to widen Highway 99 to six lanes from Manteca to the Crosstown Freeway in Stockton years ahead of schedule — will cover 39.1 percent of the $11.5 billion tab.
Topping the list as the highest priority are upgrades to the Highway 99/120 Bypass/Austin Road interchanges. The $76.7 million project is aimed to address issues that not only create delays and slow traffic to a crawl at times but are a contributing factor in many of the 300 plus accidents that occurred in 2017 mostly along the 120 Bypass corridor prior to reaching the Highway 99 interchange. The goal is to have the improvements completed by 2023.
Manteca Mayor Steve DeBrum, who serves on the SJCOG board and is leading the regional effort to secure support of other jurisdictions for the 120/99 project, noted tentative plans call for an election in 2020 to extend Measure K for another 20 years to assure funds will be available to build the projects.
The targeted mainline projects for the South County also include:
Widening Interstate 205 from Interstate 5 to the Alameda County line from six to eight lanes by 2026 at a cost of $298 million. The new lanes could either be high occupancy vehicle lanes or the first toll lanes during commute hours.
Widening Interstate 5 from Interstate 205 to Louise Avenue by adding a lane in each direction as well as high occupancy lanes from the 120 Bypass to Interstate 205. The project, targeted for completion by 2028 would cost $207.9 million.
Widening the 120 Bypass from four to six lanes by adding lanes on the inside median for $95.1 million. The work between Main Street and Interstate 5 is targeted for completion by 2030.
Widening Highway 99 from the 120 Bypass to the Stanislaus County line from six to eight lanes by 2032. The Wilma Avenue overcrossing, Main Street interchange, and a pedestrian bridge in Ripon would need to be reconstructed.
Widening Interstate 5 from French Camp Road to Charter Way from six to eight lanes with the new lanes being HOV designated. The project costing $97.8 million would be completed by 2038.
Widening Interstate 5 from French Camp Road to Louise Avenue from six to eight lanes with the new lanes being designated for HOV use. The project costing $193.8 million is targeted to be operational be operational by 2040.
The freeway efforts will move forward at the same time Altamont Corridor Express will implement longer trains to increase capacity. ACE, thanks to state funding from the gas tax legislation, will extend service to Ceres by 2023 with stops in Ripon and downtown Manteca.
Three other conceptual projects have been identified to improve the commute to the Bay Area but no funding has been identified. Those projects are:
uwidening Interstate 580 from Greenville Road in Livermore over the Altamont Pass to the San Joaquin County line. It may involve a westbound truck climbing lane as well as a toll lane during commute hours in each direction.
Making operational improvements to tracks over the Altamont to increase ACE capacity and speed.
Instituting ACE to BART service.
The $11.5 billion list also covers interchange projects, major roads in various cities, bus and train service, railroad crossing safety improvements as well as bicycle and pedestrian projects.
On that list is a $22.2 million bridge across the Union Pacific Railroad tracks in Manteca on Airport Way between Louise Avenue and Northgate Drive targeted for a 2034 completion date. There is also a bridge over the tracks on Roth Road between Manteca and Lathrop that is being planned. The goal is to have that bridge open to traffic by 2020 at a cost of $29.1 million.

What the highest priority
project for mainline highways will involve at 99 & 120 Bypass
To relieve the back-up on the eastbound 120 Bypass as it squeezes down to one lane to reach Highway  99 southbound is not as simple as adding another lane. The plan requires braided ramps, so-called because they employ short connectors from one ramp to reach another similar to what you encounter driving the Interstate 680/580 interchange in Pleasanton.
It would double the capacity to handle eastbound 120 Bypass traffic heading south on Highway 99 toward Modesto.
It would double the capacity to handle northbound Highway 99 traffic heading west on the 120 Bypass toward Main Street.
It would have the exit lane for Austin Road for traffic traveling east on the 120 Bypass start where the southbound Highway 99 transition lane now starts and then parallel the transition lane and Highway 99 before swinging to the southwest to intersect Moffat. It would then continue as a two-lane road and swing back heading east to T-intersect with Austin Road.
It would have the exit lane for Austin Road for southbound Highway 99 traffic start just past the crossover bridge for the 99 to 120 Bypass westbound and 120 Bypass to Highway 99. That ramp would then become a bridge over the 120-99 transition lanes before joining the Austin Road exit ramp that starts on the 120 Bypass to create a two-lane ramp as it continues paralleling the 99 freeway,
It widens the 120 Bypass from a point west of Main Street to the Highway 99 interchange to three lanes in each direction. That will also require the 120 Bypass bridges over Van Ryn Avenue as well as Moffat Boulevard and the Union Pacific Railroad tracks to be widened to three lanes in each direction as well.
It would create a new Austin Road northbound on-ramp at a T-intersection with the ramp first heading to the southeast and curving back under the freeway. It will parallel the northbound Highway 99 freeways and part of the transition ramp from northbound 99 to the westbound 120 Bypass until a point where traffic originating on Austin Road that wants to head to the 120 Bypass can do so at a braid connecting it to the northbound 99 to westbound 120 Bypass.  Traffic from Austin Road wanting to head north on Highway 99 would continue on Austin Road onramp and merge with the freeway north of the where the transition ramp from the eastbound 120 Bypass merges with northbound Highway 99.
Moffat Boulevard would no longer connect directly to Austin Road. There would, however, still be an onramp to southbound Highway 99 that would be accessed from a connector road to Austin Road.
A new one off ramp would be built from northbound 99 to Austin Road
The Frontage Road that intersects with Austin Road would be shifted to the east.
Highway 99 southbound from the 120 Bypass would be widened from four to five lanes.
Highway 99 northbound from Austin to the 120 Bypass would be widened from four to five lanes.
Highway 99 to a point south of Austin Road would be widened from six to eight lanes of traffic and shifted to the east to avoid the Union Pacific right-of-way that will be double tracked to accommodate extending Altamont Corridor Express service into Ceres by 2023.
The Austin Road bridge across Highway 99 would also be extended across the railroad tracks to eliminate an at grade track crossing much like was done with Jack Tone Road in Ripon.
Austin Road across Highway 99 will be widened from two lanes to four lanes and include left turn pockets much like the new Lathrop Road bridge that’s part of the Highway 99 interchange.
Woodward Avenue would no longer connect with Moffat due to the need to move the railroad crossing further south for the off ramp traffic to reach Austin Road.

Draft environmental impact for regional transportation plan
SJCOG has prepared a Draft Program Environmental Impact Report in accordance with the California Environmental Quality Act for the 2018 Regional Transportation Plan/Sustainable Communities Strategy document.
The Draft Program EIR is available electronically at  A print copy, including the Technical Appendices, is available for review at the SJCOG Offices, 555 East Weber Avenue, Stockton. You may submit a request for a print copy or CD by calling (209) 235-0600. 
The comment period started Tuesday and ends April 26.  Public hearings will be held on April 4 at noon at the Lathrop City Council Chambers, 390 Towne Centre Drive, and on April 26 at 4 p.m. at the SJCOG offices, 555 E. Weber Ave., Stockton.
To contact Dennis Wyatt, email

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