Get ready for a weekend trip to the Manteca Costco to become even more maddening than it already is.

And don’t be too surprised if a supermarket pops up along Airport Way near Daniels Street.

As for using Airport Way, you’d better hope the city is able to break ground on the McKinley Avenue/120 Bypass interchange as they plan to later this year.

That’s because the biggest concentration of housing ever to break ground in Manteca is doing so just across the 120 Bypass from Costco and the Stadium Retail Center.

Four developments clustered along the western end of the Woodward Avenue — the road that once led to the Manteca Waterslides — are going forward basically at the same time.

One has started building homes, one is doing site work and the other two have obtained funding and city approval to start on infrastructure prior to the final map being approved.

That doesn’t mean much to most people. But here’s what does: When completed, the four neighborhoods will add 3,349 housing units to  Manteca.

Based on current yield rates — a term for the average number of residents per dwelling — the homes will house more than 10,000 people.

To put that in perspective Ripon has 16,100 residents while Escalon — to the east of Manteca via East Highway 120 — has 7,538 residents.

Those 3,349 homes are expected to add a minimum of 15,000 vehicle trips a day to Manteca streets with Woodward Avenue taking the biggest hit.

Even after Oakwood Shores — the 400 plus home gated community that rose form the demise of the Manteca Waterslides where $1 million resale homes have become the norm — started building a decade ago, Woodward Avenue beyond McKinley Avenue has been low key.

Beyond Oakwood Shores where Woodward Avenue turns south there is access to the Oakwood Mobile Home Park, the rural Wetherbee Lake neighborhood and the Turtle Beach Resort before the San Joaquin River blocks any more movement to the west.

The new developments have been tagged with putting in a number of roundabouts, including on Woodward Avenue, to keep traffic moving and bring a degree of safety. Unlike roundabouts farther to the east on Woodward Avenue, the ones going in will be larger.

If the new homes follow the established pattern of new development in Manteca at least one member of 80 percent plus of the new households will be commuting.

And the bulk of those commuters will head west to the Bay Area.

That means when the McKinley Avenue interchange opens, traveling  west on the 120 Bypass will become even more of a chore. It will dump traffic on to the Bypass just 1½  miles from its merging with Interstate 5 which is about a half mile merge to Interstate 205 and the route to the job rich Bay Area as well as Tracy employment centers.

Between  McKinley Avenue and Interstate 5 is the Yosemite Avenue interchange.

Up until a year ago traffic at the interchange was minimal. It still is even after the opening of Wayfair’s distribution center. But that will change.

Work is underway on more than 5 million square feet of distribution center space that will be served by the Yosemite Avenue interchange. That is in addition to 57 acres of commercial and office space also approved by the City of Lathrop.

The impact of 10,000 more residents will be felt citywide given most commercial is away from the southwest Manteca area. But assuming Manteca will get all of the taxable sales dollars isn’t a sure thing. The Lathrop Target off Interstate 5 will be roughly the same distance as the Manteca Target on Yosemite Avenue. As an added bonus the Lathrop Target will have a Sprouts market opening up near it next year.

The fact developers are now sinking money into the ground, there has been an uptick in retail interest in Manteca including several supermarkets.

The school-aged population generated from the homes are beyond walking distance to the closest school which is Veritas Elementary off Atherton Drive across from The Promenade Shops at Orchard Valley.

Sierra High will get a significant inflow of students. Just like East Union and Manteca high schools, the plan is to take it up eventually to a programmed capacity of 2,200. It will require additional classrooms at the Sierra High campus.

Keep in mind the southwest housing stampede is in addition to new projects that have broken ground in various parts of Manteca in the past year that will eventually add another 1,600 homes plus another 800 where the developer is poshing for the initial ground breaking.

The homes being built in southwest Manteca include:

*The 656-home Cerri neighborhood now under construction along the extension of McKinley Avenue south of Woodward Avenue.

*The 1,237-home Manteca Trails that Raymus Homes is breaking ground directly to the west of Cerri and south of Woodward Avenue

*The 637-home plus 200 apartment Oakwood Trails that has just been approved to start site work on the northside of Woodward Avenue across the street form Manteca Trails and west of Oakwood Shores.

*The 319-home Denali neighbor where grading and infrastructure work is now underway

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com