Elements of the Transportation Impact Study for El Dorado County Community Development Agency

IV. ELEMENTS

A. Executive Summary The Transportation Impact Study (TIS) shall include an Executive Summary that presents the key findings, including project impact assessments and proposed mitigation measures.

B. Project Description The applicant shall provide a comprehensive project description that includes, at a minimum:

• A detailed discussion of the specific land uses intended for the site.

• Identification of the current land use designation(s) as defined by the El Dorado County General Plan.

• A statement confirming the project’s consistency with the current land use designation(s).

• Identification of the Traffic Analysis Zone(s) (TAZ) in which the project is located.

• Consideration of site access alternatives.

• A project location map depicting the proposed project in relation to surrounding communities, roadways/highways, major watercourses, and delineation of the applicable TAZs.

• A project boundary map illustrating the site location, off-site roadways, and other transportation features, including proposed transit, bicycle, and pedestrian facilities.

• A site plan showing the internal traffic circulation system, parking layout, and any transit, bicycle, or pedestrian facilities, including access and egress points.

• A tabular summary listing the types of development and land uses, including quantities such as floor area, acreage, number of employees, dwelling units, or other applicable measures.

• Description of proposed construction and operational activities, including the schedule for completion and any development phasing.

• Documentation regarding potential effects on off-site transportation facilities, including transit, roadways, bikeways, and sidewalks.

• An initial estimate of the weekday Average Daily Traffic (ADT), AM and PM peak-hour traffic generation. If project-generated trips exceed 100 vehicle trips per day, additional documentation is required. Refer to Appendix C for typical project trip generation categories.

C. Study Area (Zone of Impact Identification) The study area shall be defined through a process supported by substantial evidence, ensuring it extends to cover all potential transportation impacts. Approval of study locations by CDA’s Long-Range Planning (LRP) staff is required before data collection and analysis commence. Study area boundaries should be determined based on the following criteria:

• All intersections and road segments contiguous to the project site.

• All intersections and road segments where the project would potentially worsen traffic conditions beyond the acceptable level of service (LOS) per General Plan Policy TC-Xe.

• All intersections and road segments currently operating at LOS “F” per General Plan Policy TC-Xd that may be further impacted by project traffic.

• All State Highway intersections and interchange ramps impacted by the project.

• Consultation with the California Department of Transportation (Caltrans) to assess CEQA significance levels for traffic impacts on state-controlled facilities.

D. Analysis Methodology

1. Analysis Time Periods Traffic impacts shall be analyzed using industry-standard methodologies, per the Highway Capacity Manual (HCM). The required analysis periods, determined based on project characteristics and consultation with CDA staff, include:

• Weekday AM Peak (6:00 – 9:00 AM)

• Weekday PM Peak (4:00 – 7:00 PM) Additional analysis may be required for:

• Weekday Afternoon Peak (2:00 – 4:00 PM)

• Weekday Midday Peak (11:00 AM – 1:00 PM) The selected analysis periods should capture the highest combined levels of project-generated and background traffic.

2. Trip Generation Applicants must submit a trip generation analysis estimating the number of new daily and peak-hour vehicle trips. The analysis should incorporate:

• Primary, internal, diverted link, and pass-by trips.

• Credit for existing site uses, if applicable.

• Trip generation estimates based on the latest Institute of Transportation Engineers (ITE) Trip Generation Manual.

• Justification for non-standard trip generation rates if alternative sources are used.

• A tabular summary of trip generation calculations (see Appendix D for sample calculations).

3. Trip Distribution Project trip distribution shall be based on:

• Existing travel patterns from observed traffic counts.

• Traffic assignment using the El Dorado County Travel Demand Model (TDM).

• Consideration of project access and internal circulation. The assumptions and methodology for trip distribution must be documented and approved by CDA’s LRP staff.

4. Analysis Tools

a. Forecasts Traffic forecasts shall be based on El Dorado County’s TDM for the year 2035. The following scenarios will be provided:

1. Existing (2010)

2. Near-term (10 years post-project submittal)

3. Cumulative (2035)

Forecast methodologies include:

• Using TDM data to develop future background growth.

• Applying growth factors to current year counts for unchanged intersections.

• Using TDM-projected turning movements for modified intersections.

• Ensuring consistency through review and adjustment as necessary.

b. Level of Service Analysis Level of Service (LOS) shall be assessed using:

• The latest Highway Capacity Manual (HCM).

• Software such as HCS, Synchro, TRAFFIX, or SimTraffic (as required by CDA staff).

• State facilities analysis per Caltrans standards.

LOS analysis must account for:

• Peak hour factors (PHF), heavy vehicle effects, queuing, and pedestrian crossings.

• Additional micro-simulation analysis where required.

• Verification against General Plan LOS thresholds and specific plan requirements.

c. Capital Improvement Projects The study shall reference relevant Capital Improvement Projects (CIP), including:

• Assumed roadway improvements and funding status.

• Supporting documentation and projected construction timelines.

• A listing of CIP projects available at the CDA Transportation website.

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