The northbound on-ramp and south-bound off-ramp for the Austin Road at Highway 99 interchange could disappear for at least 19 years.

It’s the current reality based on a three-phased, $132 million Caltrans project essential to address safety and operational concerns at and near the 120 Bypass/Highway 99 interchange.

The “temporary” loss of the two ramps for today’s traffic movements would have a minimal impact on Manteca based on current development.

That’s because by far the heaviest used ramps are those that move local traffic using Austin Road to and from Modesto.

In the 20-year plus growth range for Manteca that means Tracy/Bay Area bound traffic — the overwhelming bulk of Manteca’s heavy daily commute movements from southeast Manteca — will be pushed toward the Main Street and possibly Union Road interchanges on the 120 Bypass.

It would also make many urbanizations during that period east of Highway 99 in the Austin Road area extremely problematic in terms of traffic movements.

The proposed 817-home Yosemite Square project on the northeast quadrant of the Austin Road/ Highway 99 interchange is one example.

It will generate 7,741 vehicle trips daily with peak hour traffic adding 765 vehicle trips on Austin Road.

Assuming Yosemite Square is like most new Manteca neighborhoods,  close to 80 percent of the household paycheck earners will commute to Tracy and the Bay Area while the bulk will shop at places such as Costco and Walmart.

If the interchange at Austin Road was intact it wouldn’t be a major problem.

But in order for residents to reach freeways they will either have to zig-zag through South Manteca neighborhoods or else access the freeway by taking Austin Road north to Yosemite Avenue.

The two ramps have to come out in order to eliminate dangerous short merges that create safety issues and contribute to traffic congestion.

The 120 Bypass and Austin Road interchanges by modern freeway operational standards are too close to each other.

Plans are to replace ramps being taken out with long braided ramps but that won’t happen until the third phase.

The third phase will cost $62 million because it also incudes adding a third lane in each direction on the 120 Bypass from Main Stret to Highway 99.

There is $36.9 million in funds already secured to build the first phase. The initial phase will add a second transition lane from eastbound 120 to southbound 99 and replace the Austin Road interchange.

The Austin overpass  needs to be torn down since auxiliary lanes are needed on Highway 99  to provide for safe and as congestion-free  movements as possible. The overpass is not wide enough.

It will be replaced with a bridge structure that clears both the freeway and the railroad tracks.

The first phase is expected to go to bid  in the spring of 2023 with the contract awarded in the fall of 2023. Completion is targeted for the winter of 2025.

The second phase that would add a second transition lane from northbound Highway 99 to the westbound 120 Bypass is programmed to open for traffic in 2033. The third phase that involves putting the ramps back in place is programmed to open for traffic in 2042.

Local lenders are scrambling to try and secure funds that would allow the second phase work to start as soon as the first phase is done.

The $62 million need for the third phase is likely to be significantly more daunting to secure to move the work up to the point it would be able to start after the second phase is done. That assumes leaders succeed in finding federal and state money to make the second phase happen eight years sooner.

First phase also includes a new connector road from Austin Road to Atherton Drive at a point south of Woodward Avenue.

Woodward Avenue will be realigned so it crosses the tracks at a 90-degree angle.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com