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Kittitas County I Snoqualmie Pass Comprehensive Safety Plan 8 <br />Chapter 3 : Analyzing Data <br />To guide decision-making and prioritize capital and programmatic investments, the CSAP draws on a robust analysis of collision history, <br />traffic volumes, travel speeds, roadway characteristics and other contextual variables, and intersection performance. This data-informed <br />approach helps identify patterns, higher-risk conditions, and opportunities for proactive safety and mobility improvements. <br />Collision Trends <br />Between 2Ot4 and2023,tO7 collisions were <br />reported in Snoqualmie Pass, including three that <br />resulted in death or serious injury. Most collisions <br />occurred on SR 906 or the l-90 ramps, wilh 60% <br />occurring during the winter months when snow and <br />ice create hazardous conditions and Snoqualmie <br />Pass experiences a surge in visitors for ski season. <br />Speeding, distracted driving, and midblock collisions <br />were common contributing factors for both winter <br />and summer seasons. <br />Volume & Speed Trends <br />ln addition to collision data, traffic volume and <br />speed data were analyzed to assess current roadway <br />conditions and understand how capacity constraints <br />may impact safety and performance in Snoqualmie <br />Pass. Data was collected during two study periods- <br />October 2024 and February 2025. <br />Traffic volumes spiked during peak recreation <br />periods, particularly near l-90 interchanges and key <br />intersections. While capacity analysis indicated that <br />intersections operated at acceptable levels of service <br />(LOS)with relatively limited delays in both October <br />-, <br />Epl <br />I mteA or serious lnjury <br />(KSl) Collisions <br />Three Collisions (3%) <br />I Suspected Minor lnjury <br />or Possible lnjury Collisions <br />27 Collisionsl25%l <br />@ Property Damage Only <br />(PDO) Collisions <br />77 Collisions(72%l <br />and February study periods, field observations and <br />community feedback revealed that this analysis <br />represents only a snapshot in time and does not <br />fully capture the lived experience of residents and <br />visitors. On-the-ground observations during a <br />holiday weekend highlighted steadily increasing <br />congestion, high levels of street friction, and <br />conditions that contribute to safety risks, including <br />vehicles and trucks parking along SR 906, people <br />walking in narrow shoulders and along the traveled <br />way, unmarked pedestrian crossings, insuffi cient <br />parking supply, and driver confusion during peak <br />periods. Analysis of speed data revealed observed <br />speeds exceeding posted limits by up to 18 mph <br />along some segments of SR 906.. High vehicle <br />speeds are a concern given that vehicle speeds <br />greatly increase both the likelihood of a crash and <br />the severity of the outcome. <br />The data analysis confirms that there are persistent <br />infrastructural, behavioral, and seasonal challenges <br />that require targeted safety and mobility strategies in <br />Snoqualmie Pass. <br />Common <br />Contributing Factors <br />4 <br />I <br />I <br />l <br />I <br />I <br />YlGT <br />67 otl0T <br />Collisions (63%) <br />occuned during <br />the winter months <br />7 <br />5 <br />l <br />I <br />g')f.tu <br />May Jun Jul Aug Sep Oct Nov Dec <br />ir I-"r" <br />AprJan Feb Mar <br />Distracted <br />Driving <br />Midblock <br />Collision <br />Collision <br />Tlpe <br />20L4-2023 <br />. 85th percentjle speeds collected October 2O24- <br />Speeding