South Bound I-680 Conversion to Express Lanes and HOV Completion Project

PARIKH worked with HDR on all phases of the project, providing preliminary engineering, environmental assessment and documentation, through design phases. The project constructed eleven miles of express lanes, improving operations on SB I-680 decreasing congestion, and improving traffic time and reliability. The project was sponsored by Contra Costa Transportation Authority (CCTA), in conjunction with Metropolitan Transportation Authority (MTC), Caltrans, and the Federal Highway Administration and runs from the Benicia-Martinez Bridge to the city of Walnut Creek, connecting to an existing express lane which runs from Walnut Creek to San Ramon. The completion of this project creates 25 miles of continuous express lanes along the I-680 corridor in Contra Costa County.

The project included conversion of existing southbound HOV lane into a tolled express lane, and constructed a new express lane, closing an existing three mile gap in the managed lane system. Project features include freeway widening, interchange modifications, retaining walls, bridge widening, overhead sign structures, toll gantries, communications, and electrical infrastructure for the toll system. The express lane toll system utilizes congestion based pricing to manage traffic operations and maintain free-flow speeds.

This project has been selected by the ACEC to receive a California 2022 Engineering Excellence Award. Congratulations to all teams involved.