SR 99/120 interchange in and near manteca, CA; SR 99 postmiles 4.6/5.9 and SR 120 postmiles 5.1/T7.2 widen the northbound SR 99 to westbound SR 120 C

This $5,647,783 Project Grant award from the Federal Highway Administration under the Highway Planning and Construction program (CFDA 20.205) will fund the widening and expansion of the State Route 99/120 interchange in Manteca, California. Specifically, the project will:

• Widen the northbound SR 99 to westbound SR 120 connector ramp from one to two lanes
• Add an auxiliary lane in the westbound median of SR 120 from SR 99 to Main Street
• Convert the existing SR 99/120 separation structure to two lanes and construct a new separation structure for the eastbound SR 120 to northbound SR 99 connector ramp
• Construct a new northbound Austin Road on-ramp
• Rebuild the northbound off-ramp and adjacent frontage road
• Expand the northbound SR 99 auxiliary lane south of Austin Road

This grant-funded project aims to enhance traffic flow and improve transportation infrastructure in the Manteca area. The award was made on March 10, 2025 to the California Department of Transportation (Caltrans), which will serve as the primary awardee and project manager.

Project description

SR 99/120 interchange in and near manteca, CA; SR 99 postmiles 4.6/5.9 and SR 120 postmiles 5.1/T7.2 widen the northbound SR 99 to westbound SR 120 connector ramp from one-lane to two-lanes; add an auxiliary lane in the existing median of westbound SR 120 from SR 99 to main street; convert the existing 99/120 separation structure to two lanes and construct a new separation structure to serve the eastbound 120 to northbound 99 connector ramp; construct the northbound austin road on-ramp; rebuilding the northbound off-ramp and adjacent frontage road; expanding northbound 99 auxiliary lane south of austin road.