Congestion Relief

State Route 99/120 Connector - San Joaquin Council of Governments

The San Joaquin Council of Governments’ highway-to-highway 
State Route 99/120 Connector project in Manteca will benefit 
everyone living, working and traveling in San Joaquin County 
as it improves safety, eases traffic congestion, enhances 
mobility and goods movement, and reduces greenhouse gas 
emissions for better air quality. The first phase of the project 
includes adding a lane to the eastbound State Route 120 ramp 
to southbound State Route 99 and replacing the Austin Road 
bridge over State Route 99 with a longer structure that will 
span the added lane and Union Pacific Railroad tracks. The 
half-mile Singh Street was built to link Austin Road and East 
Atherton Drive to ensure direct access to Moffat Boulevard 
without major rerouting once the Austin Road overcrossing is in place. Other infrastructure – wider Woodward Avenue, 
and new traffic signals, railroad crossings, sidewalks, curbs, and striping on surface streets – will improve the traffic flow 
between the highway to Manteca’s surface streets. For updates on this project and to signup for notifications via email 
and text, visit the State Route 99/120 Connector Project Updates webpage.

I-580 and International Parkway/Patterson Pass Road - Tracy & Caltrans

Measure K funds are contributing toward design and construction of a diverging diamond interchange at Interstate 580
and International Parkway/Patterson Pass Road in a project by Tracy and Caltrans. This project will ease traffic congestion 
projected by commercial and residential growth in the area. Relieving traffic congestion will shorten travel times, reduce 
greenhouse gas emissions and improve air quality. This will be one of the first diverging diamond interchanges in the state. 
The first was at State Route 120 and Union Road in Manteca, which is also building two others. The innovative design 
reduces traffic congestion, improves safety for pedestrians, cyclists and motorists, is less expensive to build than a 
traditional highway interchange, and has a smaller footprint. It also requires traffic on the overpass to drive briefly on the 
opposite side of the road from what is normal. Work on this DDI is expected to continue until summer 2026.

State Route 120/McKinley Avenue Interchange - Manteca

The State Route 120/McKinley Interchange project added new and 
easy access to Manteca’s Family Entertainment Zone, more than 120 
acres, 50 retail spaces, 25 dining options, and 10 entertainment 
venues anchored by the Big League Dreams Ballpark Complex and 
Great Wolf Lodge. The interchange enhances safety for motorists, 
bicyclists, and pedestrians, reduces congestion on State Route 120 
and local roads, improves traffic circulation, and accommodates 
forecasted traffic demand and planned growth in the area. The 
interchange is open to the public.

State Route 120/Main Street Diverging Diamond Interchange - Manteca & 
Caltrans

As with the diverging diamond interchange (DDI) at State Route 120 and Airport Way, the DDI at State Route 120 and Main 
Street in Manteca will improve local and regional traffic circulation and cut traffic congestion. The improvements will 
enhance traffic operations and mobility, allowing traffic to move more freely through the interchange, and accommodate 
traffic now and in the future. There are also improvements for cyclists and pedestrians. The current interchange was built in 
the 1970s and met the needs of the area, but since then the city population has grown and State Route 120 traffic has 
significantly increased. Now there’s also a large commercial development near the interchange. The benefits include improved 
traffic flow and safety. This DDI will also improve spacing between State Route 120 and Main Street. Costs can be lower 
because the right-of-way footprint is typically smaller than a typical interchange and the current overcrossing’s structure can 
be used for the new interchange. Other benefits include improved local and regional traffic circulation, reduced congestion by 
enhancing traffic operations and mobility, and bicycle and pedestrian improvements. The DDI at this interchange will 
accommodate the city’s future traffic demands. Measure K funds were used by the city to complete the project study report 
and Measure K funds will be used to complete the Project Approval and Environmental Document.

SR 120/Airport Way Project

Louise Avenue Pavement Improvement Project – Manteca

Measure K funds were used in Fiscal Year 2023-24 to help Manteca rehabilitate deteriorated pavement on Louise Avenue 
from Main Street to State Route 99. The project includes removing existing asphalt where needed, installing new asphalt,    
updating the striping and pavement markings, installation of bike lanes, and Americans with Disabilities Act curb ramp 
improvements. The improvements will enhance safety for pedestrians, cyclists and motorists. Work began in June 2024  
and continued into October 2024.