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Part of bid to reduce carnage on eastbound 120 Bypass where your chances of getting in an accident are 6 times state average
A 2018 accident on the eastbound 120 Bypass approaching the Highway 99 interchange.

Caltrans is hoping a few more signs and modified lane striping will help reduce the carnage on the eastbound 120 Bypass while they work toward getting the first phase of a $131.5 million project designed to improve vehicle movements and capacity in place by 2023.

It is the result of a new partnership between Caltrans, San Joaquin Council of Governments the City of Manteca and the California Highway Patrol. The agencies recently formed a Road Safety Assessment Task Force to review traffic  accidents on the 120 Bypass, discuss safety concerns, and collaborate to identify meaningful steps to help limit the likelihood of future accidents.

“The City is in teamwork with Caltrans and CHP to help make Route 120 safer, and we are appreciative of these initial Safety Corridor improvements in partnership with them,” noted Manteca Mayor Ben Cantu.

Work on installing new signs and modifying road striping starting this month include:

Watch For Stopped Vehicle signs will be installed on both shoulders, just west of the Main Street overcrossing, to help reduce the number of rear-end collisions.

Stay In Lane signs will be installed on both shoulders, just west of Van Ryn Avenue bridge, to help reduce the frequency of vehicles queue-jumping for southbound Highway 99 and sideswipe collisions.

New chevron markings and lane delineation will be installed in the gore point (neutral area) between the connector ramp lanes from eastbound 120 Bypass to northbound and southbound Highway 99, to discourage drivers from making last-minute lane changes and cutting off other motorists. 

Installation of 2,700 feet of wider, 8-inch, double-white striped lane delineation, from just east of the Main Street overcrossing to the southbound Highway 99 connector ramp, is also to discourage last-minute lane changes.  It should be noted that crossing over double-white stripes is a traffic violation.

“Caltrans in partnership with the City of Manteca and CHP encourage SR-120 travelers to watch for stopped traffic approaching eastbound to southbound Route 99,” urged Caltrans District 10 Director Dan McElhinney. “These traffic signing and striping changes are to help inform drivers to avoid distractions and to please drive safely.”

Chances of getting in

accident on eastbound

120 bypass six times

higher than state average

It is the latest effort Caltrans is undertaking to improve driving safety on the eastbound 120 Bypass where your chances of getting in a traffic accident is six times higher than the state average for freeways.

Previous changes have included upgrades to the electronic traffic advisory signs. The state also placed signs advising the Highway 99 split is approaching at Airport Way, Union Road, and Main Street. Not only is it to remind commuters but also warn those not familiar with the bypass of the split.

Caltrans — in environmental documents for the three phase project — indicated that high traffic volume during the afternoon commute that sees in excess of 2,000 vehicles an hour trying to go from the eastbound 120 Bypass to southbound Highway 99 creates a backup for at least a half mile for a number of hours. The state notes that motorists — impatient about the delay — will use the fast lane or inside lane to travel as far as they can to the split and then cutback into the much slower moving traffic in the right lane. That leads to rear-end collisions and an accident rate six times higher than the average for a California freeway.

There was an accident every 15 hours at the interchange and freeway approaches in 2018 that required Manteca Fire Department units to respond.

First phase of major

upgrades starts in 2021

Caltrans has identified the $52.5 million funding for the first phase of the project. The goal is to award the contract in the summer of 2021, start construction in the fall of 2021, and have work on the first phase completed by the fall of 2023.

The first phase involves:

widening the eastbound 120 Bypass to southbound 120 Bypass from one to two lanes.

removing the Austin Road overcrossing and replacing it with a longer span that ultimately would allow eight freeway lanes plus auxiliary lanes on Highway 99. The replacement bridge would span the Union Pacific Railroad tracks as well eliminating the at-grade crossing on Austin Road.

adding a new connector road from Austin Road to East Woodward Avenue. The existing railroad crossing on East Woodard Avenue would be modified to confirm with the new connector road and provide access to Moffat Boulevard.

modifying the existing northbound Austin Road exit ramp to conform with the higher overcrossing profile of the replacement bridge.

closing the northbound onramp and the southbound off-ramp for Highway 99 at Austin Road. The length of the closure is currently estimated at 9 years. Reopening of the replacement ramps will depend on the availability of funding for the third phase.

The second phase costing $26 million would:

widen the connector from northbound Highway 99 to the westbound 120 Bypass from one to two lanes.

convert the existing structure crossing Highway 99 to the 120 Bypass to two lanes.

construct a new separation structure to serve eastbound 120 Bypass traffic to the northbound Highway 99 connector ramp.

add a westbound auxiliary lane on the 120 Bypass from the Highway 99 interchange to Main Street.

add an eastbound auxiliary lane on the 120 Bypass between Main Street and Highway 99.

The third phase costing $53 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 loop 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 loop 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 it being necessary 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.

In order to do so the ramp for southbound Austin would start for eastbound 120 Bypass traffic at a point near the Bypass crossing of Moffat Boulevard and the railroad tracks while  the ramp for southbound 99 traffic to access Austin would start prior to the 120 Bypass connector flyover.

Caltrans estimated the second and third phases could start construction in March 2030 and be completed by September 2031. Since it is highly dependent on funding, it is possible there could be a nine year gap between the two phases.

 The eastbound 120 Bypass sees about 31,000 vehicles on an average day with almost one out of six vehicles being trucks.

To contact Dennis Wyatt, email