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<br />Marian Meadows Rezone and Subdivision Final Environmental Impact Statement 3-61 <br />introduces a number of features into street design to slow traffic and render streets safer for local residents <br />(Gilman 2007). <br />In addition to use by adjacent residents, roads in the area serve a variety of transportation modes. <br />Snowmobiling is a popular winter activity of local residents and others. Rental opportunities for visitors <br />are also provided by local outlets. Snowmobiling is permitted along Sparks Road and Railroad Street <br />with a 25-mph posted speed limit. A number of formal and informal snowmobile trails are used in the <br />vicinity. <br />All-terrain vehicles (ATVs) are popular during the spring, summer, and fall seasons and often use Sparks <br />Road to access other areas. Similar to snowmobiles, residents and visitors on ATVs are common <br />throughout the study area. <br />Although not specifically designed for or encouraged, other non-motor vehicle uses of the local roads is <br />generally considered acceptable given the low traffic volumes, weather conditions, and proximity to <br />vacationing areas that promote outdoor activities. <br />8 What are the existing standards that define “acceptable” traffic conditions? <br />Within the study area, the acceptable standards for traffic conditions are defined by the LOS. Kittitas <br />County and WSDOT identify LOS C or better as their standard for acceptable operations in rural areas, <br />such as the study area. LOS is an estimate of the quality of performance of transportation system <br />operations. The most common industry standard for evaluating traffic operations is based on the <br />Transportation Research Board’s (TRB) Highway Capacity Manual (HCM), Special Report 209 (TRB <br />2000). Using this methodology, traffic conditions are assessed with respect to the average intersection <br />delay (in seconds of delay per vehicle) and uses the letter “A” to describe the least amount of congestion <br />and best operations and the letter “F” for the highest amount of congestion and worst operations. The <br />2000 HCM LOS ratings and criteria for signalized and unsignalized intersections are shown in Table 3-4. <br />Table 3-4. Level of Service (LOS) Ratings for Signalized <br />and Unsignalized Intersections <br />LOS <br />Rating <br />Average Delay for <br />Signalized <br />Intersections <br />(seconds/vehicle) <br />Average Delay <br />for Unsignalized <br />Intersections <br />(seconds/vehicle <br />) <br />A 0 – 10 0 – 10 <br />B > 10 – 20 > 10 – 15 <br />C > 20 – 35 > 15 – 25 <br />D > 35 – 55 > 25 – 35 <br />E > 55 – 80 > 35 – 50 <br />F > 80 > 50 <br />Source: HCM (2000)