Scope of the Transportation Impact Study (TIS)
The scope and content of a Transportation Impact Study (TIS) are determined by several factors, including the location and scale of the proposed development, the prevailing transportation conditions in the surrounding area, and the technical concerns raised by decision-makers and the public. A well-prepared TIS ensures that potential transportation impacts are adequately analyzed and addressed in accordance with the policies and regulations established by the El Dorado County Community Development Agency (CDA).
Development of Study Scope and Assumptions
The preparation of a TIS begins with the applicant’s traffic engineer drafting a scoping memorandum to outline the study’s scope and content. This memorandum is submitted to the CDA’s Long Range Planning (LRP) staff for review and approval before any detailed analysis begins. The purpose of this scoping memorandum is to establish the parameters of the study, ensuring that all relevant transportation impacts are considered.
Following the approval of the scoping memorandum, the applicant’s traffic engineer prepares an “assumptions” memorandum, which details land use and operational assumptions, as well as traffic study modeling inputs and methodologies. This assumptions memorandum undergoes a similar review and approval process by the CDA’s LRP staff, who may modify the proposed assumptions to align with best practices and County standards.
Required Elements of a Transportation Impact Study
Once the scope of work is finalized, the applicant’s traffic engineer proceeds with preparing the draft TIS for the proposed project. The TIS must be a comprehensive document incorporating relevant text, tables, maps, and drawings to effectively communicate the results of the traffic analysis. Supporting materials, including traffic count data and Level of Service (LOS) calculations, must be appended to the main report. Additionally, electronic copies of LOS calculations and any simulation program files must be included with the submission.
Upon receipt of the draft TIS, CDA’s LRP staff conducts a thorough review and provides written comments identifying any necessary revisions. If deemed necessary, a meeting may be arranged between the LRP staff and the applicant’s team to discuss the report’s findings, raise questions, or address identified deficiencies. The applicant is responsible for making the necessary revisions based on the feedback received and submitting a finalized TIS for approval. The final TIS must be signed and stamped by a registered Civil Engineer or Traffic Engineer, licensed and in good standing with the State of California Board of Professional Engineers, Land Surveyors, and Geologists.
Essential Components of a TIS
To ensure a standardized and thorough analysis, a TIS prepared for a project in El Dorado County must include the following key elements:
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Executive Summary – A concise summary of the project, analysis findings, key transportation impacts, and proposed mitigation measures.
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Project Description – A detailed description of the proposed development, including land use, project size, location, access points, and anticipated opening year.
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Study Area (Zone of Impact Identification) – Identification of the geographic area where the project is expected to influence traffic conditions, including adjacent roadways and intersections.
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Analysis Methodology Description – Explanation of the methodologies and tools used for assessing traffic impacts, including modeling software and assumptions.
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Impact Significance Criteria Definition – Definition of the criteria used to determine whether the project’s transportation impacts are considered significant under CEQA.
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General Plan Consistency Considerations for Cumulative Impact Analysis – Evaluation of the project’s consistency with the transportation policies and goals outlined in the County’s General Plan.
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Traffic Impact Analyses Scenarios:
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Existing Conditions – Analysis of current traffic volumes, roadway configurations, and LOS at key intersections and corridors.
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Existing Plus Project Conditions – Assessment of how project-generated traffic would affect existing conditions without additional planned improvements.
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Near-Term (+10 Years) Conditions – Evaluation of anticipated traffic conditions in the near future based on planned development and infrastructure changes.
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Near-Term Plus Project Conditions – Analysis of near-term conditions with the inclusion of project-generated traffic.
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Cumulative Conditions (When Required) – Examination of long-term future traffic conditions based on regional growth and planned infrastructure projects.
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Cumulative Plus Project Conditions (When Required) – Assessment of cumulative future conditions factoring in the proposed project’s traffic impacts.
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Transportation Impact Mitigation Identification – Development of mitigation measures to address identified transportation impacts, ensuring compliance with County regulations.
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Other Transportation-Related Impacts and Mitigation Considerations – Discussion of additional transportation concerns such as pedestrian and bicycle access, transit accommodations, and safety considerations.
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Technical Appendices – Inclusion of supporting materials such as traffic count data, LOS calculations, signal warrant analysis, and any other relevant technical documentation.
TIS Report Format and Submission
For consistency and ease of review, the final TIS must adhere to the report format outlined in Appendix B. This standardized format ensures that all required elements are properly documented and facilitates efficient review by County staff. The TIS should be prepared in a manner that allows replication by peer consultants or County staff, ensuring that findings and conclusions are based on transparent and reproducible methodologies.
By following these guidelines, the TIS will provide a comprehensive and objective analysis of the project’s transportation impacts, assisting decision-makers in evaluating proposed developments and ensuring that appropriate mitigation measures are implemented to maintain safe and efficient transportation networks within El Dorado County.
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