Gary Singh sees the best chance Manteca has to develop an employment center with minimum traffic impacts as well as a long-term solution to address existing and future congestion south of the 120 Bypass with what are arguably the two most ambitious freeway ramps ever proposed in San Joaquin County.

The ramps are part of what could end up being a three phased $141.7 million project that will create positive impacts reverberating up and down the Northern San Joaquin Valley and into the Bay Area for the movement of goods and commuters.

Councilman Singh, as Manteca’s representative on the San Joaquin Council of Governments, is working with other leaders in the county to secure funding for the 120 Bypass/Highway 99 interchange project designed to improve traffic flow, reduce congestion, and reduce safety concerns.

First phase involves

extending Betschart Drive

The first phase — a $51.6 million endeavor that adds a second transition lane from the westbound 120 Bypass to southbound 99, replaces the Austin Road interchange, and reconfigures segments of Woodward Avenue and Moffat Boulevard — is on target to break ground in spring of 2022.

If all goes well, work on the first phase of the project would be completed in winter of 2023.

There is a $7 million funding shortfall SJCOG is working on bridging to completely fund the $51.6 million first phase.

It includes an estimated $4 million Manteca needs for its share of widening the replacement bridge to four lanes that will also clear the Union Pacific Railroad tracks.

Elected city leaders opted to pay for widening the replacement bridge that will have a lane configuration similar to the Lathrop Road overcrossing of Highway 99. By widening the bridge now instead of 10 to 15 years down the road when traffic required it, the city could easily save $10 million to $15 million given the replacement bridge clears the freeway and the railroad tracks.

Singh is working to get the cost of that $4 million city share — as well as the cost of a proportion of two key replacement ramps — collapsed into the Public Facilities Improvement Free for major roads that is assessed on all growth whether it is residential, commercial, or industrial.

The Austin Road project wasn’t on the city’s radar when Caltrans came up with the holistic solution for the 120 Bypass congestion and safety issues. That is why it wasn’t factored into the road growth fee now in place.

Two ramps carry

$43 million price tag

The first phase temporary eliminates the Austin Road off ramp for southbound 99 and the on-ramp for northbound Highway 99. That’s because the cost of the two ramps could easily increase the cost of the first phase by $43 million or almost 80 percent more.

Caltrans and others didn’t want to delay the implementation of the work that would be the most effective at addressing congestion and operational issues that have made the last two miles of the eastbound 120 Bypass the most deadly stretch of freeway on the Northern San Joaquin Valley. A Caltrans environmental report for the project noted your odds of getting into an accident in those two miles are six times greater than the state average for freeway.

The reason for the high cost is the ramp configuration needed.

The biggest problem is the proximity of the Austin Road interchange with the 120 Bypass interchange. They are way too close from an operational standpoint for smooth and safe merging.

In order to do the first phase to add an additional transitional lane from the eastbound 120 Bypass to southbound Highway 99 space was needed for an additional merge lane under the Austin Road overcrossing. And ultimately for the most effective solution overall, the replacement bridge needs to accommodate eight thru lanes passing below Austin Road.

The least expensive solution would have been to permanently close the two ramps in question. That, however, would have led to surface street traffic issues that would have put extensive pressure on the Main Street interchange along the 120 Bypass and would have forced Manteca to pursue and pay for a $100 million interchange farther to the south on Highway 99 that would require shifting the freeway to the east.

The solution to make it

work are braided ramps

The solution requires braided ramps.

The southbound off ramp for Austin Road requires eastbound 120 Bypass traffic to merge onto an off-ramp just past the Main Street on-ramp. This would require widening the 120 Bypass crossings over both Van Ryn Avenue and Moffat Boulevard. It would then travel alongside the transition lanes headed south on Highway 99.

Meanwhile southbound Highway 99 traffic would need to merge onto an off-ramp shortly after the 120 Bypass exit to access Austin Road. That would require the ramp to cross under the transition lanes for the 120 Bypass traffic heading north on 99 and the then over the two southbound transition lanes headed toward Ripon and merge with the off-ramp starting after Main Street on the 120 Bypass.

Once they meet and “braid” the ramp will end up about where it is now to connect with Moffat.

Traffic trying to reach Austin would head northwest on Moffat, turn left onto a new alignment of Woodward, then turn left on Atherton and travel to an extension of Betschart Drive that will T-intersect into Austin

The on-ramp would be a similar braided design. It would start at a T-intersection with Austin where southbound Austin traffic would turn left and northbound traffic would turn right.

The ramp would run along Highway 99 and then the transition ramp for northbound 99 to the westbound 120 Bypass where a “braid” splits off traffic heading west toward Main Street on a ramp that merges with the transition lanes from Highway 99.

At the braid traffic can continue northward to merge with 99 beyond the interchange.

 The southbound off-ramp for Austin would cost $24.75 million or basically what the city spent to covert the Union Road/120 Bypass interchange into a diverging diamond last year.

The on-ramp with could $18.7 million.

Currently both are included in the third phase.

Second phase involves adding

2nd transition lane from north-

bound 99 to westbound 120

The second phase costing $28.1 million without the two ramps involves widening the 99 northbound transition lanes to two. Doing so would require a new eastbound 120 to northbound 99 ramp and bridge across Highway 99.

The current ramp and bridge would be converted to two lanes heading west by removing the median barrier on the existing ramp.

The second phase’s final design is expected to be completed in the spring of 2024 with construction underway by summer of 2024, and work completed by the fall of 2025.

Singh is working with SJCOG to find money so one or both ramp projects can be moved up from the third phase to the second phase.

At the minimum he’d like to see the on-ramp wedded with the second phase.

Singh noted that would provide freeway access from southwest Manteca while efforts are made to secure additional funds for the off-ramp.

During the interim traffic heading to Austin Road would need to take the freeway exits on the 120 Bypass and then turn left on Atherton Drive. They would travel to the new Betschart Drive extension and connect with Austin Road with a T-intersection.

Under such a scenario, should that happen, $21 million would need to be spent in the third phase to place auxiliary lanes on Highway 99 must of the distance toward Jack Tone Road to effectively make the freeway eight lanes.

To contact Dennis Wyatt, email dwyatt@mantecablletin.com