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Public Works designs roadways pursuant to national standards (American Association of State <br />Highway and Transportation Officials) for: horizontal and vertical curves and associated roadway <br />geometrics. <br />Public Works collected traffic data on No. 6 Road between Vantage Highway and Kittitas Highway <br />(MP 0.00 to MP1.02) between October 5, 2023, and October 12, 2023. Traffic data collected is <br />provided in EXHIBIT 1. <br />DISCUSSION: <br />Responding to a request received to reduce posted speed on Kittitas Highway, Public Works also <br />collected data on No. 6 Road, deploying traffic data collectors October 5, 2023, and collected through <br />October 12, 2023. Traffic and speed data was collected at mile post 0.89. This segment has 20 percent <br />truck traffic within the average daily traffic distribution of vehicle size. Traffic at this location is split <br />50.6% southbound and 49.4% northbound. Overall 85th percentile speed at this location is 51.0 MPH <br />with directional speeds of 52.0 MPH southbound and 50.0 MPH northbound. <br />85th percentile speeds show traffic is operating at a speed at the current speed limit of 50 MPH. There <br />are 33 approaches along this segment of No. 6 Road, primarily serving residential and agricultural <br />uses. There were 27 recorded crashes along this roadway in the previous five years. The majority were <br />located at the intersection of Kittitas Highway at No. 6 Road. <br />Responding to concerns regarding the number of crashes reported at the intersection of Kittitas <br />Highway at No. 6 Road, Public Works collected traffic and speed data of the intersection approaches. <br />Public Works deployed traffic data collectors October 5, 2023, and collected through October 12, <br />2023. Data was collected at each leg of the intersection, including Kittitas Highway MP 2.23 and 2.49, <br />and No. 6 Road MP 0.89 and 1.15. Traffic data results are provided as EXHIBIT 2. <br />The 2009 Manual on Uniform Traffic Control Devices (MUTCD) section 213.07 Multi -Way Stop <br />Applications (EXHIBIT 3) provides guidance on intersection control. MUTCD guidance includes <br />review of crash data and traffic volumes of both the primary street (Kittitas Highway) and the minor <br />street (No. 6 Road) of the intersection. Crash data reviewed was found to meet Criteria 2B.07(B) of <br />five or more reported crashes in a 12-month period that are susceptible to correction by a multi -way <br />stop installation. There were nine reported crashes in the previous 12-month period (EXHIBIT 4). <br />Seven of these crashes are susceptible to correction by a multi -way stop installation. One crash was a <br />rear end collision, and one crash was attributed to a vehicle malfunction. <br />FISCAL IMPACTS: <br />Posting the new 35 MPH speed signs is expected to cost in the range of $2,000. Public Works <br />budgets for this activity annually in our road maintenance budget. <br />The cost of posting the intersection of Kittitas Highway at No. 6 Road as an all -way stop is expected <br />to be $10,000. <br />ATTACHMENTS: <br />EXHIBIT 1: No. 6 Road Speed study results <br />EXHIBIT 2: Intersection Traffic Data results <br />EXHIBIT 3: 2009 MUTCD Section 2B.07 <br />EXHIBIT 4: Crash Data Count <br />Page 2 of 6 <br />PUBLIC WORKS BOARD OF COUNTY COMMISSIONERS ENGINEER'S REPORT <br />