19.51.070 Impact analysis.
Analysis of traffic generation and transportation effects shall use the following methodology:
A. Study Area. The study area shall be defined as the area that includes all of the transportation system that is projected to be used by a minimum threshold of fifty new peak hour trips. The study area shall not be limited to the city limits, but shall include the county, state, and other city roadways. For projects that have region wide traffic impacts, the city traffic engineer may limit the scope of the study area. Region wide impacts will be determined on a case-by-case basis in consultation with the county, state, tribal, and other appropriate jurisdictions.
B. Horizon Year. The traffic analysis shall include impacts for the future horizon year. The horizon year shall generally be based on the year the proposed project is expected to be completed, but shall be:
1. The horizon year shall generally be based on the year the proposed project is expected to be completed.
2. The horizon year shall be no earlier than the final year of the city’s adopted capital improvement plan (six years).
3. The horizon year shall be no earlier than six years from the date of the completed project application.
4. If a project will generate new traffic for more than six years, the horizon year shall be the planning horizon for the land use and transportation elements in the comprehensive plan that is in effect at the time of the complete application (i.e., the years remaining between the time of the complete application and the end of the planning horizon used for the adopted comprehensive plan).
5. For any project, the city traffic engineer may make a case-by-case determination of the horizon year, including extension of the horizon year, or the requirement for intermediate analysis years, for projects that are built in phases or designed to be built over a number of years.
C. Base Traffic and Growth Factor. The base traffic for the traffic analysis shall include existing traffic plus traffic generated by any project in the study area that has been previously reviewed under SEPA, any proposed project currently under review by the city, and any additional traffic reasonably foreseeable as deemed appropriate by the city traffic engineer. This additional traffic may include trips generated in other jurisdictions. The applicant may request to use a specific growth factor if the applicant can demonstrate with analysis that such a growth factor is appropriate for the project location and is not inconsistent with the comprehensive plan (including SEPA or other traffic analysis supporting the comprehensive plan). The city traffic engineer may require that a different background growth factor be used when site specific information supports a different factor. Where there is no area specific information, a four percent background growth factor compounded annually shall be used to project the existing traffic to the required horizon year.
D. Trip Generation and Distribution. The traffic analysis shall assign and distribute the proposed project’s peak hour trips down to and including the minimum threshold level of fifty new project-generated peak hour trips. Unless otherwise required or approved by the city traffic engineer, trip generation rates shall conform to the latest edition of Institute of Transportation Engineers (ITE) Trip Generation Manual. Where proposed traffic or transportation impacts are not predominantly automobile (for example, trucks, trailers, rail, air or waterborne traffic), the analysis shall identify the type of traffic and mode split in the generation and distribution analysis. Directional distribution shall be determined in consultation with the city traffic engineer. For large projects or in areas experiencing substantial development activity, the city traffic engineer may require directional distribution and trip assignment to be performed using computerized model.
E. Level of Service. The method for analyzing the level of service when required (see EMC 19.51.090) shall be the current edition of the Transportation Research Board Highway Capacity Manual and its related computer software, or a method otherwise approved by the city traffic engineer.
F. Other Items. The traffic analysis shall include applicable items in sections of Exhibit 1, attached to the ordinance codified in this chapter, as well as other items relevant to the particular project being reviewed, as determined by the city traffic engineer. (Ord. 3774-20 § 5(Z) (Exh. 3), 2020.)