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Transportation and Traffic Impacts

Yorke prepares California Environmental Quality Act (CEQA) traffic sections supported by technical studies for CEQA environmental documents that include the following elements:

  • Analyze project plans to assess construction traffic impacts;
  • Assist in selecting a traffic engineer with experience working with local jurisdictions and who has performed traffic modeling for similar projects;
  • In cooperation with the local and state jurisdictions and the traffic engineer, determine a rational study area and trip generation rates for the project components; and
  • Determine the appropriate mitigation measures to reduce traffic impacts to below significance levels.

Based on the CEQA guidelines, there are several traffic-related significance criteria, including whether a project would result in:

  • A conflict with an applicable plan, ordinance, or policy establishing measures of effectiveness for the performance of the circulation system, taking into account all modes of transportation, including mass transit and non-motorized travel, and relevant components of the circulation system, including but not limited to intersections, streets, highways and freeways, pedestrian and bicycle paths, and mass transit;
  • A conflict with an applicable congestion management program, including but not limited to level of service standards and travel demand measures, or other standards established by the city or county traffic management agency for designated roads or highways;
  • A change in traffic patterns, including either an increase in traffic levels or a change in location that results in substantial safety risks;
  • A substantial increase in hazards due to a design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment);
  • An inadequate emergency access; and
  • A conflict with adopted policies, plans, or programs regarding public transit, bicycle, or pedestrian facilities or that would otherwise decrease the performance or safety of such facilities.

For most projects, short-term construction traffic impacts from equipment deliveries, materials deliveries, demolition debris and excavated soil haul-away trips, and worker commuting are the primary concerns during the construction phase of the project. Long-term operational traffic impacts from project-related traffic on local and regional roadways, e.g., surface streets and freeways, can be an issue if these roadways are already congested or if project-related traffic causes roadways to have a significantly greater quantity of traffic in relationship to their design capacity.

For projects which have high trip generation rates, such as large residential projects, shopping centers, or industrial projects, a significant impact to local and state transportation facilities may occur depending on the existing operational year conditions, the study area, and the project-specific trip generation rate.

Our standard approach to traffic analysis is both quantitative and qualitative. The approach to construction traffic impacts is to determine – in cooperation with the contractor – the expected number of construction equipment and materials deliveries, debris and soil haul trips, and worker trips based on similar projects and project-specific data. Based on the number of trips, the existing traffic conditions, and the acceptable level of service capacity of roadways that would be utilized during the project’s construction phase, the traffic impact of construction can be determined.

The approach to operational traffic impacts includes development of project-specific trip generation rates and study areas in cooperation with local planning and transportation departments and, if needed, Caltrans. We also enlist a qualified traffic engineer with experience in both the type of project that is being built and the jurisdiction where the project is located. If necessary, Yorke works with the local and state jurisdiction and the traffic engineer to develop a feasible mitigation plan that will reduce project-related significant traffic impacts to less than significant. Using data provided by the jurisdiction and the traffic engineer’s quantitative traffic modeling technical summary, model output, and/or traffic counts, Yorke will develop a defensible traffic impact section ready for your CEQA environmental document, such as a Mitigated Negative Declaration (MND). Our qualitative evaluations of project-related impacts are useful for transportation facilities such as public transportation, non-motorized transportation such as bicycles, and pedestrian facilities.

Main Office:

31726 Rancho Viejo Rd. Suite 218
San Juan Capistrano, CA 92675