I-880/Decoto Road Interchange Modernization Project
The I-880/Decoto Road Interchange is a major facility that serves both local and regional traffic and sits at the nexus of the Dumbarton Bridge Corridor and Interstate 880. The interchange serves commuters traveling in the Dumbarton Corridor between the East Bay and Peninsula/South Bay, providing a primary connection between regional housing and job centers. Decoto Road itself serves as a primary transit route, connecting the Union City BART Station to and from destinations on the Peninsula west of the Dumbarton Bridge. Decoto Road also provides access between Fremont and Union City for pedestrians and bicyclists to connect to the Dumbarton Bridge, the only continuous, permanent multi-use San Francisco Bay crossing. The I-880/Decoto Road Interchange Modernization project will upgrade this major interchange to include transit priority treatments and safe biking and walking facilities. Improvements to the I-880/Decoto Road interchange were among the top priorities identified in Fremont’s Mobility Action Plan, a community-developed 5-year plan for local action and regional advocacy launched by Fremont’s Mayor and City Council in response to community concerns about traffic throughout Fremont.
As has been documented in the Decoto Road Multimodal Corridor Plan effort, there is a need to modernize the interchange. Decoto Road passes over I-880 at the western end of the project area, at which point its designation changes to SR 84. The partial cloverleaf interchange currently provides full access to and from eastbound and westbound Decoto Road/SR 84 and northbound and southbound I-880. The existing Class II bike lanes pass through the interchange, connecting to a Class I path on the north side of SR 84 west of I-880. However, there is a gap in the eastbound direction when passing the I-880 northbound loop on-ramp, and navigating the interchange requires executing a weave maneuver with vehicles entering and exiting the freeway, which many bicycle users may describe as highly uncomfortable. There is no sidewalk on the north side of the interchange, which requires pedestrians accessing the Class I path to travel out of the direction and cross the free ramp at eastbound Decoto Road and northbound I-880. In addition, vehicular congestion and antiquated, vehicular focused design features within the Decoto Road Interchange inhibit reliable transit operations and reduce safety and comfort for pedestrian and bicycle users within the interchange.
- Enhance bicycle and pedestrian access, comfort, and safety to and through the I-880/Decoto Road Interchange, and connect to future bikeway/pedestrian facilities to the east along Decoto Road.
- Improve transit operational efficiency and reliability along Decoto Road through the I-880/Decoto Road Interchange.
- Maintain operational efficiency and improve safety for all travel modes.
Four interchange alternatives have been developed by the project team based on existing topography and other constraints, of which three alternatives (see below) have been selected for preliminary traffic and environmental impact analysis with Caltrans. It is important to note that the alternative layouts are still in the preliminary scoping stage and is intended to be conceptual during the current project scoping phase. Construction level plans will be completed during the future design phase of the project.
The Project is currently in the scoping phase, which involves City and Caltrans collaboration and will take approximately one year to complete. The scoping phase is being funded by an Alameda CTC grant and will identify a series of feasible alternatives to carry forward to subsequent phases of development. The timeline for the environmental clearance, final design, and construction has not yet been determined.
The conceptual cost range for the project is between $10 million and $30 million depending upon which alternative is selected.
Eric Hu, Principal Transportation Engineer