Express Lane Completion
Part-time
Transit Lanes
Express Lane Completion
Shared
Mobility Hubs
Mobility as
a service
Automated
Driving Systems
Advanced
Technologies
FINAL ENVIRONMENTAL DOCUMENT AVAILABLE
The Final Environmental Impact Report/Environmental Assessment (Final EIR/EA) is available for review.
Overview
Contra Costa Transportation Authority (CCTA), in partnership with California Department of Transportation (Caltrans), is proposing to complete the Interstate 680 (I-680) Northbound Express Lane Completion Project (Project) to address the existing express lanes gap, relieve congestion, reduce travel delays, and improve operations. The proposed Project would construct a northbound express lane from Livorna Road to State Route 242 (SR-242) and convert the existing northbound High-Occupancy Vehicle (HOV) Lane from SR-242 to north of Arthur Road near Martinez to an express lane – which means both HOV and single-occupancy drivers who pay a toll can use the lane. The proposed Project has four build alternatives (1C, 2, 3 and 5) and one no-build alternative.
Why Do We Need This Project?
The need for the Project to address existing transportation problems within the Project Study Limits are:
- Congestion: Northbound I-680 general-purpose lanes within the Project Study Limits experience substantial congestion – over 30 minutes of delay – during peak hours.
- System Continuity: There is a 7.5-mile gap in the existing northbound I-680 managed lane system between Livorna Road and SR-242; system continuity is lacking through this area, diminishing the effectiveness of the managed lane system and increasing travel time for all users.
- Operational Improvements: The weaving movement between Lawrence Way and Treat Boulevard creates a bottleneck on northbound I-680 and a traffic queue as far back as Livorna Road during the afternoon peak traffic period. The situation is compounded by the gap in the managed lane system.
Purpose
The purpose of the proposed Project is to:
- Reduce peak-period congestion and delay on northbound I-680.
- Encourage use of HOV and transit services.
- Offer non-carpool eligible drivers a reliable travel time option.
- Optimize use of the existing HOV lane capacity in the I-680 corridor to better meet current and future traffic demands.
- Reduce travel time and improve travel time reliability for travelers in the corridor.
Environmental Phase
The proposed Project is subject to State and Federal environmental requirements. The Final EIR/EA has been prepared in compliance with California Environmental Quality Act (CEQA) and National Environmental Protection Act (NEPA). The Final EIR/EA includes an analysis of the proposed build alternatives.
Project Location
Preferred Alternative
Among the four build alternatives evaluated, Alternative 2 would provide the most overall operational benefits and best meets the Project’s purpose and need. Alternative 2 would reduce peak-period congestion and delay on northbound I-680, encourage use of HOV and transit services, offer non-carpool eligible drivers a reliable travel time option, optimize use of the existing HOV lane capacity in the I-680 corridor to better meet current and future traffic demands, and reduce travel time and improve travel time reliability for travelers in the corridor.
The Preferred Alternative (Alternative 2) consists of the following elements:
- Reduce the northbound express lane gap through lane addition from Livorna Road to north of South Main Street, and from south of North Main Street to I-680/SR-242 interchange.
- Convert the existing northbound HOV Lane from I-680/SR-242 interchange to north of Arthur Road near Martinez to an express lane.
- Construction of braided ramps that separate the Treat Boulevard off-ramp traffic from the North Main Street/Lawrence Way on-ramp. The Treat Boulevard off-ramp would be elevated over the Lawrence Way on-ramp to make merging onto the freeway safer and more efficient.
Other Alternatives Considered
The other alternatives considered are proposed as follows:
- Alternative 1C: Closes the northbound express lane gap through lane addition and southbound I-680 realignment.
- Alternative 3: Closes the northbound express lane gap through lane addition, southbound I-680 realignment, and construction of braided ramps.
- Alternative 5: Reduces the northbound express lane gap by general-purpose (GP) lane conversion and constructing braided ramps.
- No-Build Alternative: Leaves northbound I-680 in its current configuration without any improvements.
Project Alternatives Studied and Considered
Learn more about the Project alternatives:
Design Elements Included in the Proposed Build Alternatives
A combination of these design elements appears in the four proposed build alternatives.
- Braided Ramps: Separate the Treat Boulevard off-ramp traffic from the North Main Street/Lawrence Way on-ramp with braided ramps. The Treat Boulevard off-ramp would elevate over the Lawrence Way on-ramp to make merging onto the freeway safer and more efficient.
- Southbound I-680 Realignment: Realign lanes on southbound I-680 between South Main Street and North Main Street in Walnut Creek to make room for a new northbound express lane, which provides a continuous express lane through the SR-24 interchange.
- Lane Addition: Add an express lane by widening northbound I-680.
- HOV Lane Conversion: Convert the existing HOV lane to an express lane between SR-242 and north of Arthur Road near Martinez, providing access to high occupancy vehicles and toll-paying drivers.
- GP Lane Conversion: Convert the existing inside lane to an express lane without widening.
A variety of environmental issues were evaluated for impacts as part of the Draft EIR/EA including:
Air Quality
Biological Resources
(habitats, threatened & endangered species, wetlands)
Climate Change / Greenhouse Gases
Community Impacts
Cultural Resources
(archaeology, historic buildings & structures, tribal cultural resources)
Sea Level Rise
Traffic/Transportation
Utilities
Cumulative Impacts
Floodplains
Geology, Soils & Seismicity
Growth
Hazardous Materials & Waste
Land Use
Noise
Paleontology
Visual Resources
Water Quality, Hydrology & Stormwater
Vehicle Miles Traveled (VMT)
Senate Bill 743, a California law, changes how public agencies like CCTA measure transportation project impacts and how agencies decide what projects to build. The law requires using Vehicle Miles Traveled (VMT) to measure how many total miles are traveled by vehicle within the project area, whether by residents, visitors, shoppers, or employees.
Project Launch: Public Scoping Meeting Archive
Scoping was conducted from June 15 to July 9, 2020, and provided an opportunity for the public and agencies to provide input on the Project prior to the preparation of the environmental document. Below are materials from the public scoping process.
Draft EIR/EA Circulation
On June 5 and 6, 2024, public hearings/meetings about the Draft EIR/EA were held and provided an opportunity for attendees to ask the Project team questions and provide formal comments. The comment period was from May 8 to June 24, 2024.
A recording of the virtual meeting, presentation, and the Draft EIR/EA are available below.
Draft Environmental Impact Report/Environmental Assessment
Notice of Availability
Notice of Completion
Virtual Hearing/Meeting Recording
Hearing/Meeting Presentation
Cost Estimates
The cost estimate for the Preferred Alternative (Alternative 2) is $312 million and approximately $200 million for SB 743 mitigation. These preliminary cost estimates will be refined during the design phase. This Project is eligible for multiple funding source types, including:
- Federal
- State
- Regional
- Local
Project Schedule
Part-time
Transit Lanes
Shared
Mobility Hubs
Automated
Driving Systems
Express Lane Completion
Mobility as
a service