A replacement overpass and an extended sewer line beneath Highway 99 is laying the ground work for a new frontier of Manteca growth — expanding east of Austin Road.

Currently, Manteca’s eastern city limits stop at Austin Road northeast of Highway 99.

And while there are no annexations in the hopper currently to head east of Austin Road toward Jack Tone Road, the two key infrastructure projects are likely to perk up interest in developing the corridor.

The extension of a sewer trunk line beneath Highway 99 just east of where Woodward Avenue ends at Moffat Boulevard is being looped into the East Yosemite Avenue line via a new line under Austin Road.

The punching through of a sewer main line beneath the 120 Bypass in the late 1990s opened the proverbial floodgate for residential development in south Manteca.

The Airport Way corridor is now struggling with the torniquet effect that the two lane overpass at the interchange with the 120 Bypass has been creating.

The McKinley Avenue interchange that opened over two years to the west of Airport Way is continuing to take pressure off of the corridor.

That is also true of a move underway to eventually build a six-lane diverging diamond replacement overpass on Airport Way.

Austin Road, by contrast will soon have a four-lane overcrossing of Highway 99 in place.

It has been seen for years as a key piece of  a puzzle to get development started on the 1,080-acre Austin Road Business Park south of the interchange with zoning in place that could add housing to accommodate another 10,800 residents.

There are also a number of nearby larger parcels not annexed to the city that would be in the path of logical growth that is being made possible with the replacement of the problematic 1955 old Austin Road crossing.

Not only was it a narrow two-lane bridge but it had an at-grade rail crossing on its southern foot where more than 40 trains often pass on any given day.

Toss in the commute backup that typically had traffic backing up for upwards of a quarter of a mile between Moffat and Woodward and you create a situation that adding much growth feeding into the interchange would have had a severely negative impact.

The replacement bridge clears the railroad tracks as well as Moffat.

The northbound onramp and southbound offramp won’t be replaced until the next phase of the 120/99 connector project being conducted by the San Joquin Council of Governments

But when they are in place the biggest traffic flow hindrance — and most expensive project to widening the Austin Road corridor — will have been completed ahead of development of any consequence.

And while Austin Road northeast of the interchange where the 797-home Cedar Point neighborhood is now being built as well as farther north are lined with small rural residential parcels, that is not the case several hundred yards from Austin Road behind the homes in question.

Having in place the sewer line and two of the biggest infraststrucre projects needed to serve a wide swath of developable land with in the Austin Road corridor’s reach means they are feasible financially to add on to via extending the pipeline or widening the road.

As such, it is likely to raise the allure of development north of the Highway 99 interchange as well as what the city already expects to happen to the south.

The new overpass is targeted for completion later this year.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com