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Clark County, WA Safety Management Program

Learn about Clark County's Safety Management Program framework, goals, and project development process for improving traffic safety.

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Clark County, WA Safety Management Program

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  1. Clark County, WA Safety Management Program Western District ITE Monterey, CA June 23rd, 2019

  2. Agenda • Background • Goals • Safety Management Program • Systemic Safety Improvement Program

  3. Background • Historically County had used traditional method of managing traffic safety • Vision of a reliable and defensible technique to screen and prioritize projects • Traditional methodology dealt with absolutes in terms of safety improvements • Highway Safety Manual can provide quantitative value for nominal safety improvements resulting in estimates for benefit cost ratio

  4. Goals The Clark County Safety Program was established with the following goals: • Better identify locations for potential safety improvement projects • Use an objective data-driven process to prioritize locations throughout the County • Develop projects for high priority locations • Quantify and compare the benefit-cost ratio of any potential improvements OVERALL: Best use of County Funding

  5. Safety Program

  6. Data – Due Diligence Data located in County’s GIS database: • Crash data • Date • Severity • Crash type • Roadway inventory data • County road log number and mileposts • Functional classification • Traffic volume data (ADT) • Posted speed (miles per hour)

  7. Safety Management Program Framework Based on the AASHTO Highway Safety Manual’s (HSM) Roadway Safety Management Process.

  8. Network Screening Process

  9. Network Screening – Reference Populations

  10. Network Screening – Reference Populations

  11. Network Screening – Performance Measures • Crash-Critical Crash Rate Ratio • Frequency of Fatal and Severe Injuries • Excess Proportion of Specific Crash Type • Annual Equivalent Property Damage Only Score Performance measures were selected to account for crash severity, frequency, and types.

  12. Network Screening – Excess Proportion Crash Types *Primary Crash Type

  13. Network Screening – Performance Measures Maximum total score of 5.0

  14. Project Development and Ranking Process

  15. Priority Locations • Top 5% of locations from network screening • 180 intersections • 400 segments • Evaluate top sites based on recent context: • Remove locations where improvements are already identified • Remove locations that may be impacted by other construction

  16. Site Reviews • Field visits at priority intersections and corridors • Includes the following items: • Review crash trends to identify potential problems at the site (collision reports) • Observe traffic operations • Measure sight distances, as needed • Drive approaches or corridors to evaluate from users perspective

  17. Crash Prediction Long-Term Expected Average Number of Crashes • minimizes influence of the randomness of crashes

  18. Project Packages and Benefit/Cost • Two tiers: near-term and long-term project packages • Tier I—Lower cost, higher ease of implementation • New signs and striping • Signal timing and phasing changes • Shoulder rumble strips • Tier II—Higher cost, lower ease of implementation • Intersection lighting • Adding turn lanes • Widening shoulders • Guardrails

  19. Project Packages and Benefit/Cost

  20. Intersection Prospectus Sheet

  21. Segment Prospectus Sheet

  22. Systemic Safety Improvement Program • Provides low cost safety countermeasures that can be applied at various locations with the same risk factors • Toolbox of treatments for County’s most prevalent risk factors: • Rural road curves and grades on high-speed roadways • Rural road fixed objects, including trees, stumps, posts, poles, embankments, or ledges • Rural two-way stop controlled intersections • Urban signalized intersections • Pedestrian crossings on multi-lane urban roadways

  23. Top Locations for Consideration Rural Curves • NE Lucia Falls Rd between NE 172nd Ave and NE Sunset Falls Rd • NE 119th St between NE 119th St and NE 172nd Ave • NE RistoRd between NE 207th Ave and NE 227th Ave Rural Slopes • NE WH Garner Rd to NE Kelly Rd, continuing to NE Yacolt Mountain Rd • NE Sunset Fall Rd between NE Deer Rd and NE Lucia Falls Rd • Rawson Rd between NE 271st Ave and NE 139th St Rural Fixed Objects • NE Lucia Falls between NE 172nd Ave and NE Sunset Falls Rd • Washougal River Rd between County Line and SE 17th St • Connection between NE 27th Ave at NE Blair Rd and NE 39th St at NE 292nd Ave Rural Two-Way Stop-Controlled Intersection Corridors • NW 199th St between 41st Ave and NE 29th St • Intersections created by NE 82nd St, NE 259th St, NE 72nd St, and NE Manley Rd • NE 182nd St between NE RistoRd and NE 119th St • SE Blair Rd between SE Washougal River Rd and WA-500 Signalized Intersections • NE 99th St and NE HWY 99 • NE 78th St and NE HWY 99 • NE St Johns Rd and NE 78th St • NE Covington Rd and NE 76th St Pedestrian Corridor • NE 99th St between NE Hazel Dell Ave and NE 25th St • NE 78th St between NE Hazel Dell Ave and NE St Johns Rd • NE HWY 99 between Minnehaha St and NE 104th St

  24. Questions Ejaz Khan, P.E.Clark County, WashingtonEjaz.Khan@clark.wa.gov Courtney Furman, P.E.Clark County, WashingtonCourtney.Furman@clark.wa.gov

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