I-580/680 Interchange Modification Project

The purpose of this project is to study various alternative alignments for a direct connector High Occupancy Vehicle (HOV) Lane from westbound Interstate 580 to southbound Interstate 680, and eventually, from northbound Interstate 680 to eastbound Interstate 580.

Caltrans is currently developing conceptual alignments with the preparation of a Project Study Report/Project Development Support. A consultant team provided by the Alameda County Congestion Management Agency (ACCMA) is evaluating options to address key commute movements currently experiencing significant congestion in and around the 580/680 interchange.

The proposed project is located in the Cities of Dublin, Livermore, and Pleasanton along westbound I-580 from Greenville Road to the east and San Ramon Road to the west, including the interchange of Interstate 580 and Interstate 680.

Interstate 580 currently experiences serious congestion while carrying substantial traffic volume through the study area during peak hours. Long-range projections indicate an increase in person trips along this freeway section associated with the continuing development along the project corridor and in the Central Valley. Travel demands and urban growth projections indicate that if no improvements are made, unacceptable levels of service would extend for longer periods of time, over longer segments during peak travel periods.

There is a critical need to eliminate existing and projected freeway congestion by improving the people carrying capacity of the route and interchange and to reduce the number of accidents. Improvements are also needed to allow for the continuity of the proposed interregional express bus/HOV system along Interstate 580 and Interstate 680. Express buses and carpooling increase effective capacity by reducing the number of cars on the highway, thereby also reducing congestion and delay in the mainline lanes.

Express bus lanes support express bus service by helping buses stay on schedule, and as a result, improving the reliability of the transit system. Direct ramps from the express bus lane to the East Dublin/Pleasanton BART Station will complete a critical link in the mass transit system in the Tri-Valley area. Traffic flow is improved because the designated HOV lanes encourage HOV drivers to stay in one lane, rather than add to the number of vehicles changing lanes, which further slows traffic.

These improvements must be cost effective and minimize impacts to the environment to the maximum extent feasible.

The main goals of the project study and development support are to:

• Increase capacity of westbound I-580 and at the I-580/I-680 Interchange.

• Improve traffic operations and safety on I-580 and reduce peak hour traffic congestion on westbound I-580.

• Facilitate the efficient flow of goods and services through this area.

• Improve traffic operations on arterial streets adjacent to the corridor.

• Facilitate the use of mass transit (express bus) and High Occupancy Vehicles (HOV) by providing connections to future express bus/HOV lanes on I-580 and I-680 to and from the south, and access to the East Dublin/Pleasanton BART Station by express bus to and from the I-580 express bus/HOV lane.

• Conform to state, regional, and local plans and policies.

- Go to Printable Fact Sheet
- Go to More Detailed Drawing