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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 />geometries. <br />On August 21, 2023, Public Works (PW) received a request to study Kittitas Highway between <br />Ellensburg City limit to No. 6 Road (MP 1.03 and MP 2.36) and to lower the speed limit from 50 <br />MPH (EXHIBIT 1). Responding to the request, PW set traffic collection devices on the road segment <br />for a one -week period (September 13, 2023 — September 20, 2023). Based on the characteristics of the <br />roadway, traffic and speed data were collected at three locations, MP 1.45, 1.73 and 2.14. Speed study <br />results are provided as EXHIBIT 2. <br />DISCUSSION: <br />The first segment, with data collected at MP 1.45, has 18 percent truck traffic within the average daily <br />traffic distribution of vehicle size. Traffic at this location is split 50.2% eastbound and 49.8% <br />westbound. Overall 85th percentile speed at this location is 51.8 MPH with directional speeds of 52.6 <br />MPH westbound and 51.1 MPH eastbound. <br />The second segment, with data collected at MP 1.73, has 20 percent truck traffic within the average <br />daily traffic distribution of vehicle size. Traffic at this location is split 57.8% eastbound and 42.2% <br />westbound. Overall 85th percentile speed at this location is 55.1 MPH with directional speeds of 54.0 <br />MPH westbound and 56.3 MPH eastbound. <br />The third segment, with data collected at MP 2.14, has 17 percent truck traffic within the average daily <br />traffic distribution of vehicle size. Traffic at this location is split 49.5% eastbound and 50.5% <br />westbound. Overall 85th percentile speed at this location is 55.1 MPH with directional speeds of 54.9 <br />MPH westbound and 55.3 MPH eastbound. <br />85`h percentile speeds in both directions (east and west) are within acceptable performance limits given <br />the current 50 MPH speed limit. Trip distribution within the first segment is 50% at MP 1.45. This <br />segment has an 85% speed of 52 MPH. Trip distribution of the second segment is 58% eastbound and <br />42% westbound with an 85 h percentile speed of 55 MPH. Trip distribution of the third segment is 50% <br />eastbound and westbound with an 85`h percentile speed of 55 MPH. <br />There were 37 recorded crashes along this roadway in the previous five years. The majority were <br />located at the east end of the traffic segment study, the intersection of Kittitas Highway at No. 6 Road. <br />There are thirty-eight approaches within this section of roadway. <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 />ATTACHMENTS: <br />EXHIBIT 1: Request for speed reduction <br />EXHIBIT 2: Speed study results <br />Page 2 of 4 <br />PUBLIC WORKS BOARD OF COUNTY COMMISSIONERS ENGINEER'S REPORT <br />