Interstate 5 Sperry Road Interchange

Project Description

The California Department of Transportation, in conjunction with Stanislaus County and the City of Patterson, proposes to construct improvements to the Interstate 5(I-5)/Sperry Road interchange, in Stanislaus County approximately 2.5 miles west of the City of Patterson. The City of Patterson is sponsoring the project and will be the lead for the design phase. The project would improve operations, enhance safety and increase the capacity of the interchange to accommodate the anticipated demand associated with recent and planned development adjacent to the interchange and in the City of Patterson.

The project proposes to upgrade the I-5/Sperry Road interchange. Improvements would include widening Sperry Road from 2-lane to 4-lane and widening or reconstructing the on- and off-ramps. Sperry Road will be widened in each direction between Del Puerto Canyon Road and 150 ft east of the California Aqueduct. Typically, the widening along Sperry Road is approximately 18 feet. However, additional widening is necessary at the approaches to the ramp intersections as well as the Rogers Road intersection to provide the required turn pockets.

Retaining walls will be constructed along both sides of Sperry Road under I-5, and the Sperry Road Bridge at the California Aqueduct will be widened to accommodate the wider roadway. Excavation will be required to construct the pavement structural sections and retaining walls needed to facilitate the roadway widening under the freeway. Existing tall embankment slopes will need to be widened along Sperry Road, east of the interchange.

Project Benefits

Purpose

• Increase the capacity of the interchange to accommodate existing and future traffic demands
• Improve operations and the movement of goods
• Enhance safety

Need

Improvements to the interchange are necessary to meet the increasing traffic demand associated with continued and planned commercial and industrial growth in the City of Patterson. Currently, the southbound off-ramp intersection operates at level of service (LOS) F in the PM peak period. By 2040, both ramp intersections are predicted to operate at LOS F during both the morning and afternoon peak traffic. Additionally, the project is anticipated to enhance the safety of motorists using this interchange, particularly the southbound off-ramp, which has an elevated incidence of vehicle accidents, as indicated in Section 4C Collision Analysis of this report.