McKinley Avenue might be more aptly named “Avenue If.”

The Manteca City Council is spending more than $1.5 million in federal funds for designing a McKinley Avenue interchange at the Highway 120 Bypass that will get built if Manteca can secure about $25 million to build it.

Part of that money to build the interchange will come from a massive Lathrop residential and business park development planned just a stone’s throw to the northwest if Manteca prevails in a lawsuit against the City of Lathrop.

Money for the interchange construction could also come from the Manteca Redevelopment Agency if the state doesn’t pull the plug on RDAs throughout California.

If the interchange is built it could become a key expressway that will go south and then sweep eastward to Highway 99 if flood plain issues can be resolved and if an alignment that doesn’t create a major uproar among rural residents can be found.

The expressway itself will be built if development not only justifies it but also pays for it.

So why pursue a project with so many “ifs?”

The reason is economics. A fourth interchange on the 120 Bypass would create additional freeway frontage commercial opportunities. More specially, it could enhance Manteca’s drive to develop nearly 200 acres of city-owned property now part of the wastewater treatment plant into a regional family entertainment zone.

One project proposed alone - the Great Wolf Resort with 400 to 600 rooms, conference center, and 75,000-square-foot indoor water park - is projected to generate $4 million to $6 million a year in motel room taxes for the stressed Manteca municipal general fund.

The McKinley Avenue interchange isn’t absolutely crucial for development of the family entertainment zone. The Airport Way interchange is a mile to the east and actually closer to the proposed 30-acre Great Wolf site that is directly behind Costco. The ability to extend Daniels Street to McKinley Avenue that could connect with a 120 with a new interchange would give the family entertainment zone optimum access for traffic.

Manteca does have Measure M tax receipts, regional transportation fees, and the city’s development fees for major roads to fall back on.

The design, once it is completed, has a shelf life of about five years with Caltrans before it has to be updated.

And if it is built it doesn’t automatically mean that McKinley Avenue ultimately will connect with a new Austin Road interchange on Highway 99 that will save the 1,049-acre Austin Road Business Park expected to include housing for up to 10,000 new residents.

If the interchange is built it will give Manteca four interchanges each a mile apart along the 120 Bypass.