Scope of Work for Transportation Impact Study in the City of Walnut Creek

Scope of Work for Transportation Impact Study in the City of Walnut Creek

3.1 Traffic Impact Study Area

The study area for a Transportation Impact Study (TIS) will be determined on a case-by-case basis and must include all existing and planned streets, intersections, and transportation facilities that could be impacted by a proposed development. Factors influencing the study area include the project’s location, site characteristics, size, land use, and current traffic conditions in the vicinity of the project site.

The TIS must analyze any Route of Regional Significance that will experience an increase of 50 or more project-generated trips during peak hours (a.m. or p.m.). The designated Routes of Regional Significance in Walnut Creek include:

• Ygnacio Valley Road

• Treat Boulevard

• Geary Road

• North Main Street north of I-680

• Pleasant Hill Road

Additionally, any intersection—whether signalized or unsignalized—that is projected to receive 25 or more project-generated trips must be included in the TIS unless otherwise specified by the City Traffic Engineer.

3.2 Traffic Impact on Freeways

Any freeway segment that will experience an increase of 50 or more project-generated trips during peak hours must be included in the TIS. The analysis of freeway facilities should be included in the appendices of the report and must comply with the latest Caltrans Guide for the Preparation of Traffic Impact Studies. The current guide, as of December 2002 or its most recent version, can be accessed at: Caltrans TIS Guide.

Any correspondence with Caltrans related to freeway traffic analysis must be documented and submitted to City staff as part of the TIS.

3.3 Coordination with Neighboring Agencies

If a proposed development generates 50 or more peak-hour trips that impact transportation facilities in adjacent jurisdictions, such as BART, the Central Contra Costa Transit Authority (CCCTA), Contra Costa County, the City of Concord, or the City of Pleasant Hill, the project consultant must coordinate with Walnut Creek City staff to determine how to address these inter-jurisdictional concerns.

Issues to be considered in this coordination include compliance with the California Environmental Quality Act (CEQA) and identifying potential mitigation measures for impacts on neighboring transportation systems. Any correspondence with external agencies should be included in the final TIS.

If a consultant is conducting a study in another jurisdiction and analyzing circulation within Walnut Creek, they must adhere to Walnut Creek’s TIS Guidelines when:

• A project contributes 50 or more peak-hour trips to transportation facilities within Walnut Creek.

• The project impacts an inter-jurisdictional corridor shared with Walnut Creek.

In such cases, consultants must submit a draft scope of work to City staff for review and approval before finalizing their study. A completed TIS must be provided to the City for review and comments.

3.4 Analysis of Pedestrian, Bicycle, and Transit Facilities

A comprehensive TIS must include an analysis of pedestrian, bicycle, and transit infrastructure. The level of detail required depends on the project's location:

Downtown Projects:

• A quantitative analysis is required, including:

  • Pedestrian crossing volumes and their impact on signal timing.

  • Bicycle volumes and bikeway configurations in relation to adjacent traffic.

  • Transit stop boarding data and passenger load factors.

Projects Outside Downtown:

• A qualitative analysis is sufficient and should assess:

  • Availability and condition of pedestrian, bicycle, and transit facilities.

  • Potential project impacts on connectivity and safety.

For all projects, peak-period pedestrian and bicycle counts should be collected at study intersections, following the data collection requirements outlined in these guidelines.

3.5 City Review of Scope of Work

Before starting a TIS, the consultant must submit a written scope of work for review and approval by the City Traffic Engineer or an authorized designee. This ensures that the study effectively addresses all relevant transportation issues. The scope of work should include:

1. Project Description

   • Overview of the proposed development, including land use type and scale.

   • Expected trip generation and impact on surrounding infrastructure.

2. Project Site Plan

   • Detailed maps showing the development site and its access points.

   • Proposed changes to streets, driveways, and parking configurations.

3. Trip Generation and Estimates

   • Calculation of anticipated vehicle, pedestrian, and bicycle trips.

   • Use of industry-standard trip generation rates (e.g., ITE Trip Generation Manual).

4. Trip Distribution and Assignment Assumptions

   • Estimated travel patterns of generated trips.

   • Breakdown of trip destinations and expected routes.

5. Preliminary List of Study Intersections

   • Identification of critical intersections and roadways for analysis.

   • Justification for selected locations.

6. Identification of Transportation and Traffic Issues

   • Signal warrant analysis, if applicable.

   • Potential impacts on existing traffic conditions.

7. Site-Specific Considerations

   • Unique factors affecting the study, such as existing congestion hotspots or planned transportation projects.

Once the City approves the scope of work, the consultant may proceed with the study. However, revisions may be required based on feedback from stakeholders or new findings during the study process. Therefore, contractual agreements between the project sponsor and the consultant should allow for flexibility to accommodate necessary scope modifications.

By following these comprehensive guidelines, the TIS will provide a thorough, fact-based analysis that facilitates informed decision-making and ensures that new developments support the City of Walnut Creek’s transportation goals.

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