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2nd phase of $131.5M solution would add 2nd transition lane from northbound 99 to Bypass
As traffic on Highway 99 continues to grow the morning commute as it nears the 120 Bypass is contributing to accidents slightly over double the average for a California freeway. This is a photo of traffic on Highway 99 passing thru Ripon. - photo by Bulletin file photo

The eastbound 120 Bypass approaching Highway 99 gets all the bad press and deservedly so.

This is where an accident happened almost every 15 hours in 2018 making it the deadliest — and most accident prone — segment of freeway in the Northern San Joaquin Valley.

The accident rate in the final mile of the Bypass as you approach and pass the Main Street exit is six times the state average.

While most of those pushing for upgrades focus on this segment Caltrans has taken notice of another up and coming problem area — northbound Highway 99 as it approaches the 120 Bypass.

It is here on many weekday mornings that not only does the outside lane often comes to a stop but so does the middle lane as a number of drivers — just like they do on the 120 Bypass — wait until the last possible minute to move over so they can access the transition ramp to the westbound 120 Bypass.

The accident rate on this section of Highway 99 is now slightly more than double the state average and getting worse with each passing year.

It is why Caltrans is making funding for the fix to the northbound 99 congestion that happens primarily during the morning commute one of their top priorities.

The traffic issues, the solutions and the impact of proposed upgrades are delineated in Caltrans’ initial study with a proposed negative declaration. Copies of the Caltrans document are available at the Manteca Library, 320 W. Center St., Manteca City Clerk’s office, 1001 W. Center St., or online at the Caltrans District 10 website. Comments on the project are being accepted through May 25.

The three-phase solution to address issues surround 120 Bypass and Highway 99 movements along with those on Austin Road will cost $131.5 million. Caltrans has identified the $52.5 million funding for the first phase that will resolve the primary eastbound 120 Bypass issues that requires the replacement of the Austin Road interchange to accommodate more lanes on southbound Highway 99.  Two lanes would go from the eastbound 120 Bypass to southbound Highway 99. 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 second phase costing $26 million addresses the northbound 99 issue primarily by adding a second transition lane to the westbound 120 Bypass. The third phase costing $53 million would restore the southbound off ramp and northbound onramps at Austin Road in such a manner that they will have minimal disruption of traffic flow on both the 120 Bypass and Highway 99. The two ramps are being closed as part of the first phase.

Funding has not been identified for the second and third phases.

Impacts the first phase

will have on Manteca

Besides correcting the biggest issue — traffic congestion that triggers unsafe lane movements on the last mile of the eastbound 120 Bypass as it nears Highway 99, the first phase will also address another safety issue — Moffat Boulevard and Woodward Avenue.

Given the intersection is a key component of addressing traffic movement off and on Highway 99 at Austin Road the subpar intersection comes under the umbrella of the $52.5 million first phase.

When Woodward Avenue crossed the tracks 25 years ago it was a lightly used country road. The part of Moffat Boulevard it connected with saw little southbound traffic as congestion an dangers on the Bypass during the afternoon commute hadn’t yet prompted a number of drivers to find alternative routes. At the same time traffic on northbound Moffat was extremely light. That’s because the left exit flyover lane from northbound Highway 99 that fed directly into Moffat at a point south of the present-day Crossroads Grace Community Church was still in place. What northbound traffic was on Moffat when it was passing Woodward Avenue originated in the countryside along Austin Road. It also was not high speed as it had a stop sign where only a left turn was possible to merge with traffic coming off the freeway from northbound 99.

The solution being built in the first phase will replace the Austin Road bridge with one that passes not only above the freeway but Moffat Boulevard and the Union Pacific Railroad tracks as well. At a point where roughly the orchards are today, a new alignment of Woodward Avenue would T-intersect with Austin Road. It will then head to the northwest in a gentle “S” curve until it connects with the current Woodward Avenue alignment just east of Atherton Dive.

A short connector street between the new Woodward Avenue alignment and Moffat Boulevard would be built so that it crosses the railroad tracks at a 90 degree angle instead of the less than optimum angle it does today.

One issue the Caltrans study notes and the project doesn’t address in any phase is operational issues at the Main Street off-ramp for eastbound 120 Bypass traffic.

The study indicates service has deteriorated below the standard levels. During some points of the afternoon commute traffic is also backed up to the freeway waiting for the signal to change to turn onto Main Street.

The City of Manteca has no project on the planning horizon to widen the Main Street interchange to four lanes and upgrade the ramps.

To contact Dennis Wyatt, email