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KITTITAS COUNTY DEPARTMENT OF PUBLIC WORKS PUBLIC WORKS — BOARD OF COUNTY COMMISSIONERS ENGINEER'S REPORT — TANEUM ROAD EAST SPEED LIMIT REDUCTION REQUEST PUBLIC HEARING DATE SEPTEMBER 3, 2019 ACTION REQUESTED CONSIDER REDUCING THE POSTED SPEED FROM 50 MPH TO 35 MPH LEAD STAFF: Mark R. Cook, Public Works Director/County Engineer RECOMMENDATION: Maintain the existing speed (50 Miles Per Hour, MPH) along Taneum Road East from Mile Post (MP) 1.00 to MP 2.84. BACKGROUND: Currently the speed limit along Taneum Road East from Thorp Highway (MP 2.84) to MP 1.0 is 50 MPH, at which it transitions to 35 MPH. A county resident requested a speed reduction in this road segment in April 2019 (EXHIBIT 1). Public Works staff conducted a speed study April 29, 2019 to May 06, 2019. (EXHIBIT 2). The results of the speed study were presented to Kittitas County Commissioners during Public Works study session of July 8, 2019. Following staff's presentation, the Board of County Commissioners requested an additional study be conducted verifying the results from the first study. A second study was conducted from July 22, 2019 to July 29, 2019 and presented at study session on August 12, 2019. DISCUSSION: A variety of factors must be considered when determining safe and reasonable speed limits. The prevailing speed is a major consideration in setting speed limits. Engineers recommend setting speed limits so that 85% of the freely flowing traffic travels at or below that speed (the 85'x' percentile). Guidance is provided in MUTCD 2B.13 (EXHIBIT 3), recommending posted speed limits to be set "within 5 mph of the 85a' percentile speed of free-flowing traffic." Another consideration is the highest safe speed for which the road was designed. This takes into account road type, road geometry, and adjacent land use. Other factors include presence of non -vehicular road users, driver or vehicle characteristics, driveway density, enforcement capability, and public attitudes. The requested speed reduction along Taneum Road East (MP 1.00 to MP 2.84) does not appear to be supported by the results of the speed study, providing MUTCD guidance is followed. Taneum Road East drivers are generally doing the posted speed (51.7 MPH study 1 and 47.8/51.4 MPH eastbound and westbound study two). The vast majority of drivers are driving at the 850' percentile or within 5 MPH of the speed of free flowing traffic. Our experience in Public Works is that drivers will drive road geometry and roadside conditions at a speed that is comfortable for the driver. Artificially reducing road speed does not necessarily reduce the speed of traffic. In the case of Taneum Road Page 1 of 5 PUBLIC WORKS BOARD OF COUNTY COMMISSIONERS ENGINEER'S REPORT