Study development was in collaboration with the City of Walnut Creek, with participation from interested agencies like Caltrans, CCTA, TRANSPAC and transit service providers. Alta + Planning & Design (“consultant”), with assistance from sub-consultant DKS Associates, developed technical work for the Plan. County staff and the consultant team also gained valuable public input through multiple meetings and community workshops held between 2014 and 2017.
Overall, six Corridor Concepts (1A, 1B, 2, 3, 4, 4A) and five focused-analysis Off-Ramp Alternatives (A, B, C, D, E) were considered. The “Preferred Project” is Corridor Concept 4A combined with Off-Ramp Alternative C (i.e. “Concept 4A/Alternative C”).
Summary: Preferred Project Analysis (Concept 4A/Alternative C)
-Preferred Project design based on agency staff and public input and technical analysis.
-Provides better multi-modal balance while maintaining optimum corridor performance, minimizes pedestrian discomfort, and avoids Caltrans design exceptions.
-Includes geometric modifications to the Oak Road and I-680 Off-Ramp intersections to improve pedestrian and bicycle crossings.
Tables 1, 2 and 3 (Exhibit B) show traffic data from key locations along the Study Corridor in “existing” and “future” year scenarios. These locations would undertake the most dramatic improvements under the Preferred Project. Though comment was received during the process that removal of lanes could cause congestion impacts or shift a bottleneck, the analysis shows each key location performs optimally under the Preferred Project. Currently, Treat Boulevard from Buskirk Avenue to Jones Road is four lanes. After Jones Road, through-traffic lanes reduce from four to three. This creates congestion with vehicles needing to merge into the eastbound through lanes. The Preferred Project would create lane uniformity in the Buskirk Avenue to Jones Road segment, which will smooth traffic throughput and improve overall corridor performance in terms of delay and level of service.
In the “No Build” scenario, the Study Corridor will inevitably experience higher future traffic volumes due to typical increases in background traffic. Implementing the Preferred Project has nominal impact to overall corridor performance (Exhibit B, Table 4), and in fact improves performance at key points in the Study corridor while providing better multi-modal balance.
Next Steps
Estimated Project Cost – $2.5 million
Staff will provide updates to the Board, through the Transportation, Water, and Infrastructure Committee, at key milestones during implementation.
Secure Funding: Staff will pursue grants and other eligible sources to fund activities identified below.
Preliminary Design: Preliminary design will include detailed plans, including relatively accurate locations, dimensions, materials, and features, which will assist in developing a corresponding refined preliminary cost estimate. The preliminary plans would be the basis for environmental documents for the project. Following the preliminary design County staff may conduct additional community outreach.
Environmental Studies and Documentation: Environmental studies and findings are required to comply with the California Environmental Quality Act (“CEQA”). If using federal funds, additional documents would be required to address the National Environmental Policy Act (“NEPA”). The environmental studies must review and address a broad range of potential environmental issues.
Permits: The County will obtain the necessary permits and agreements for the project to proceed, such as an Encroachment Permit from Caltrans.
Construction Documents: The preliminary plans will be refined into final design plans that contain construction drawings, specifications, and cost estimates.
Right-of-Way Acquisition: If necessary, Real Estate Services will work with property owners to acquire easement or other type of temporary or permanent land rights to allow project implementation.
Bidding and Contracting: Contract bid documents will be prepared and the project will be advertised for public bid. The County will analyze bids and contract with the most qualified contractor.
Construction: The contactor will construct the project with County oversight.