Selecting Countermeasures

1. Module 5 Selecting Countermeasures Safety Analysis in a Data-limited, Local Agency Environment July 22, 2013 - Boise, Idaho

2. Learning Objectives • Define key concepts: • Probable contributing factors • Target crashes • List and discuss the steps in the countermeasure selection process • Explain what a crash modification factor (CMF) is and how it is used in countermeasure selection • Explain the importance of cost effectiveness evaluation • Discuss the steps in the cost effectiveness evaluation • Describe other considerations in the countermeasure selection process

3. Countermeasure Selection Principles LINKAGE

4. Probable Contributing Factors The ‘cause’ of a crash is very difficult to determine Crash reports allow us to identify probable contributing factors Crash reports reflect common factors that were present What it means

5. Probable Contributing Factors Driver inattention – slower response time Driver under the influence of alcohol and/or drugs – reduces driver capabilities Too high a speed for prevailing conditions Failure to yield right of way at a traffic signal when turning left/right Younger drivers – inexperience may create higher crash involvement risk Examples

6. Targeted solutions (counter-measures)

7. Target Crashes Key considerations: • A countermeasure usually only change one or a subset of the crashes at a site • A countermeasure may increase some crash groupings and reduce other crash groupings What it means

8. Target Crashes Run-off the road crashes Crashes involving pedestrians Red-light running crashes Angled crashes Drinking and driving crashes (behavioral) Examples

9. Target Crashes Think about your state Strategic Highway Safety Plan • What are the priorities in the plan? • Are there any of the priorities that are more prevalent on the types of facilities in your city/town/county or region? • Who are participating in the development of the SHSP? Can you partner with them? Examples: expand perspective

10. Countermeasure Selection Cost-effectiveness: • Limited resources • Desire the largest reduction in fatalities and serious injuries possible Context: • High-speed facility with limited access? • Rural town centers with vulnerable users? • Suburban arterial with driveway accesses? • Urban central business district? Factors that impact selection

11. Evaluate Countermeasures Considerations when selecting a countermeasure: • Impact on target crashes (CMF) • Frequency & severity – are we reducing the overall severity of crashes • Economic impact • Short, medium or long-term • Reliability (proven vs. experimental) • Other tradeoffs that can’t be measured Process

12. Crash Modification Factor Value that quantifies the impact on crashes/ crash groupings/ severities Example: • CMF=0.9 • If fatal and injury crashes in a particular crash type] • Before treatment = 20 crashes per year • Then after treatment = 20 x 0.9=18 crashes per year Advantage: modification indicates that countermeasures increase or decrease crashes CMF

13. Crash Reduction Factors CRF vs. CMF • If the CMF = 0.9 then the CRF = 1-CMF=0.1 • Example: • If fatal and injury crashes in a particular crash type: • Before treatment = 20 crashes per year • Reduction in crashes = 20 x 0.1= 2 crashes per year CRF

14. Proven countermeasures address crashes in focus areas: • Intersections • Pedestrians • Roadway Departure Proven countermeasuresInfrastructure FHWA Office of Safety http://safety.fhwa.dot.gov/provencountermeasures/

15. Graphics: FHWA Office of Safety

16. Roundabouts The Challenge Safety Performance Two-way STOP to roundabout: up to 82% reduction in severe (injury/fatal) crashes & 44% in all crashes Signal to roundabout: up to 78% reduction in severe (injury/fatal) crashes & 48% reduction in all crashes. • Est. 300k signalized intersections in US • 1/3 intersection fatalities @ signalized int 2,300 ped fatalities • RLR: ≈700 annual fatalities Source: Washington State Department of Transportation

17. Corridor Access Management The Challenge Safety Performance 5-23% reduction in all crashes along two-lane rural highways, and 25-31% reduction in severe (injury/fatal) crashes along urban/suburban arterials • Conflict potential at at-grade intersections (driveways, public roads) • Number & types of conflict influence safety performance Graphics: FHWA Office of Safety

18. Backplateswith Retroreflective Borders The Challenge Safety Performance 15% reduction in all crashes at urban, signalized intersections • Unintended RLR crashes Source: FHWA Office of Safety Graphics: FHWA Office of Safety

19. Longitudinal Rumble Strips & Stripes (Two-Lane Roads) The Challenge Safety Performance Center line rumble strips on: rural two-lane roads: 44% reduction of head on / fatal and injury crashes. urban two-lane roads: 64% reduction of head-on / fatal and injury crashes. Shoulder rumble strips on rural two-lane roads: 36% reduction of run-off-road fatal and injury crashes. • Roadway departure crashes: 53% of fatal crashes annually • Inattentive drivers veering out of the travel lane Graphics: FHWA Office of Safety

20. Enhanced Delineation & Friction for Horizontal Curves The Challenge Safety Performance New fluorescent curve signs or upgrading existing curve signs to fluorescent sheeting: anticipated 25% reduction in non-intersection fatal and injury crashes. Providing static combination horizontal alignment/advisory speed signs can generate a 13% reduction in all injury crashes. Refinishing pavement with microsurfacing treatment can bring about a 43% reduction in all fatal and serious injury crashes. FHWA CMF Clearinghouse • Horizontal curves: 28% of all fatal crashes • Chevron signs, curve warning signs, and/or sequential flashing beacons: anticiapated 38-43% reduction in all fatal and injury crashes. • Chevron signs on horizontal curves: anticipated 16% reduction in non-intersection fatal and injury crashes.

21. Safety Edge The Challenge Safety Performance Eliminates tire scrubbing: associated with loss of control of a vehicle • Studies suggest crashes involving edge drop-offs: 4x more likely to be fatal on similar roads Source: FHWA Office of Safety

22. Medians & Pedestrian Crossing Islands (Urban/Suburban) The Challenge Safety Performance Installing raised medians or pedestrian refuge areas at marked crosswalks: anticipated 46% reduction in pedestrian crashes unmarked crosswalk locations: anticipated 39% reduction in pedestrian crashes • >70% pedestrian fatalities at midblock locations • Vehicle speeds • >80% pedestrians die when hit by vehicles ≥ 40mph • <10% pedestrians die when hit by vehicles @ 20mph Source: FHWA Office of Safety

23. Pedestrian Hybrid Beacon(HAWK) The Challenge Safety Performance Up to a 69% reduction in pedestrian crashes Up to a 29% reduction in total roadway crashes • >70% pedestrian fatalities at midblock locations • Vehicle speeds • >80% pedestrians die when hit by vehicles ≥ 40mph • <10% pedestrians die when hit by vehicles @ 20mph Source: FHWA Office of Safety

24. Road Diet ADT< 15,000 The Challenge Safety Performance Reduce # lanes for pedestrians to cross: reduce multiple-threat crash Reduce rear-end and side-swipe crashes Improve speed limit compliance  reduced crash severity in event of a crash • >70% pedestrian fatalities at midblock locations • Vehicle speeds • >80% pedestrians die when hit by vehicles ≥ 40mph • <10% pedestrians die when hit by vehicles @ 20mph Source: FHWA Office of Safety

25. Cost Effectiveness Evaluation Reductions in crashes are considered cost savings, or benefits Select countermeasures with the most benefits Target total crashes, severe crashes, or specific crash types The how and the why

26. Cost Effectiveness Evaluation When evaluating countermeasures, compare the benefits to the cost to implement, creating a B/C ratio. • The benefits are the reduction in the frequency and severity of the target collision type(s) The larger the B/C ratio, the better the rate of return. Basic steps

27. Value of Advanced Methods The advanced statistical methods in the HSM allows us to account for regression to the mean. This gets us closer to spending our resources on safety where it is most needed, i.e. where we’ll more likely to achieve the performance. Need-based targeted investment

28. Tools & Resources (Module 6) FHWA CMF Clearinghouse usRAP FHWA Resources for Local Agencies

29. www.cmfclearinghouse.org

33. usRAP Tools Software for Network Screening Able to: • Review an entire highway network and identify improvement locations • Identify cost-effective highway infrastructure improvements Software is simple and easy to use Required input data can be assembled with moderate effort

34. usRAP Tools Software for Network Screening Identifies: • Potential locations for safety improvement projects • Candidate project types Web-based and easily accessible To be demonstrated later in the workshop Software access and training are available through AAA Foundation for Traffic Safety

35. Summary: Module 5 Match countermeasures to target crash type(s) and severity Crash Modification Factors (CMFs) • A CMF of 0.9 means we can expect to see 90% of the target crash type(s) & severities after implementation Economic evaluation of the countermeasure(s) allows us to assess return on investment Tools and resources

36. End of Module 5 Questions?