Welcome to Caltrans District 4


This Project Has Been Completed

The Project

680 graphic The scope of the I-680 Southbound Express Lane project is to widen the freeway and structures to meet current standards, construct auxiliary lanes, rehabilitate the roadway, and implement the first High Occupancy Toll (HOT) lane facility in northern California which will allow single occupant vehicles to use the HOV lane for a toll.

The project will convert the southbound HOV lane to a HOT lane in the southbound direction from Route 84 to Route 237, and will construct auxiliary lanes between Washington Boulevard and Jacklin Road. It will open the first HOT or "Express" lane in the region reducing future congestion and will provide an alternative mechanism for funding transportation projects.


The project will maximize the efficiency of I-680, encourage use of buses and carpools, open an HOV/HOT lane to create an alternative mechanism for financing transportation projects per AB 2032, and reduce traffic congestion along southbound Interstate 680 during the morning peak hour.


This project is developed through a partnership among the Alameda County Congestion Management Agency (ACCMA), the Santa Clara Valley Transportation Authority (SCVTA), the Alameda County Transportation Improvement Authority (ACTIA), and the California Department of Transportation (Caltrans).

Project Funding
This is a Proposition 1B - Transportation Bond project funded by the State Transportation Improvement Program (STIP) Augmentation and State Highway Operation and Protection Program (SHOPP) Bond programs, other State, Federal, Measure, and Local funds.

Project Schedule
Start Construction: Fall 2008
Open Express Lane: 2011

Telephone For questions regarding Ramp Metering information, please contact the Hotline at 510-286-4531.

Telephone For questions regarding Express Lane information, please contact the Customer Service Center at 511.org or 1-877-229-8655 (1-877-BAY-TOLL)

Why Southbound Only?

Prior to the addition of the high-occupancy vehicle lane (HOV) in the southbound direction on Interstate 680 in Alameda and Santa Clara Counties, severe congestion existed in both northbound and southbound directions. The congestion in the southbound direction was higher in magnitude than in the northbound direction. To improve the most severe congestion and due to limited funding, only the southbound project was constructed first. Traffic was projected to continue to grow but with the current economy the growth has slowed down. Projects are designed to accommodate 20 years of growth so it is expected that congestion will increase again in the coming years.

For northbound I-680, there is a proposed project to construct a northbound HOV lane between State Route 237 and State Route 84, and add various northbound auxiliary lanes and related improvements, similar to the southbound direction, but that and the rehabilitation of the northbound roadway are not fully funded at this time. Delays also occurred due to litigation. Once the project is fully funded and constructed, the current northbound congestion will be significantly improved.