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speed for which the road was designed. This takes into account road type, road <br />geometry, and adjacent land use. Other factors include presence of non -vehicular <br />road users, driver or vehicle characteristics, enforcement capability, and public <br />attitudes. <br />The request to reduce the speed limit on Carroll Rd is driven by a concern for safety of <br />residents entering and leaving the roadway, transverse KRD transportation <br />movements, and the use of the roadway by large farm equipment. With an increase in <br />use of Carroll Road by local commercial aggregate companies and large hay <br />transportation operations conflicts between large truck traffic and passenger vehicles <br />are increasing prompting the concerns by local residents. <br />Traffic studies show that simply lowering posted speed limits typically has little effect <br />on actual speeds without law enforcement presence. Lowering posted speeds usually <br />only reduces the prevailing speeds by one to two miles per hour, but it can increase <br />the difference in speeds, which is a common cause of vehicular crashes. In general, <br />drivers choose their speed based on what they think is a safe and reasonable speed <br />for the conditions present. <br />One factor to consider when determining a reasonable speed limit is driver <br />expectations. Most of the other roads in the vicinity of Carroll Road that are similar in <br />character, and have similar conflicting traffic movements are posted with a speed limit <br />of 50 MPH. Roads such as Badger Pocket Road, Prater Road, Denmark Road, <br />Cleman Road, Emerson Road and Sorenson Road are good references. The <br />geographic location of this roadway segment suggests that the posted speed of 50 <br />MPH is warranted. <br />There has been one recorded accident on Carroll Road in the past five years. This <br />accident occurred in 2012 and was a single vehicle accident. In mid-December 2012 <br />a passenger vehicle failed to see the stop sign at the intersection of Carroll Road and <br />Badger Pocket Road due to heavy fog. The vehicle went through the intersection <br />skidding into the south bound ditch of Badger Pocket Road and overturned, no injuries <br />were reported. <br />The 85th percentile speed at MP 0.44 and MP 0.80 was found to be 47.35 and 50.75 <br />MPH for passenger vehicles and 46.2 MPH and 49.2 MPH for large trucks. This data <br />suggests that the majority of vehicles and trucks alike are observing the posted speed <br />limit of 50 MPH. <br />Lowering the posted speed limit below the 85th percentile may potentially make the <br />road less safe as vehicles will be less likely to travel at the posted speed limit <br />adversely impacting expectations of users following the regulatory speed. <br />Although the percentage of large truck traffic is above average at 30 to 50 percent, <br />this percentage is similar to many other roads in a rural farming community like Kittitas <br />County. Please find the table below for truck percentage comparisons of similar <br />neighboring roadways: <br />• Badger Pocket Rd 30 — 60 Percent <br />Page 2 of 6 <br />PUBLIC WORKS BOARD OF COUNTY COMMISSIONERS ENGINEER'S REPORT <br />