1. 1 CEE 763 Fall 2011 Topic 3 – Safety Management Process – Other Steps CEE 763

2. 2 CEE 763 Fall 2011 2 DIAGNOSIS

3. 3 CEE 763 Fall 2011 3 DIAGNOSIS l Objective l to gain an understanding of crash patterns and causes so that potential countermeasures can be selected at the candidate sites l Steps l Safety data review: crash statistics, collision diagrams, l Assess supporting documentation l Assess field conditions l Identify safety concerns

4. 4 CEE 763 Fall 2011 4 CRASH SUMMARY

5. 5 CEE 763 Fall 2011 5 COLLISION DIAGRAMS

6. 6 CEE 763 Fall 2011 6 SITE CONDITION DIAGRAM

7. 7 CEE 763 Fall 2011 7 SELECT COUNTERMEASURES l Objective l Select countermeasures that can effectively reduce the crashes identified in DIAGNOSIS l Steps l Identify contributing factors Haddon Matrix l Select countermeasures

8. 8 CEE 763 Fall 2011 8 HADDON MATRIX Example Haddon Matrix for Rear-end Crash

9. 9 CEE 763 Fall 2011 9 CRASHES AT SIGNALIZED INTERSECTIONS l Angle crashes l Rear-end or sideswipe l Left- or right-turn l Nighttime l Wet pavement l Pedestrian/bicyclist

10. 10 CEE 763 Fall 2011 10 CRASH MODIFICATION FACTORS (CMF)

11. 11 CEE 763 Fall 2011 11 CRASH MODIFICATION FACTORS (CMF)

12. 12 CEE 763 Fall 2011 12 CRASH MODIFICATION FACTORS (CMF)

13. 13 CEE 763 Fall 2011 13 ECONOMIC APPRAISAL l Benefit-cost analysis l Change in crash l Convert benefits to $ l Estimate project costs l Benefit/cost ratio l Non-monetary considerations

14. 14 CEE 763 Fall 2011 14 ECONOMIC APPRAISAL

15. 15 CEE 763 Fall 2011 15 ANNUAL BENEFITS TO PRESENT VALUE Example: What is the benefit cost ratio for a countermeasure implementation that will cost $3,000,000, but with an annual benefit of $872,400? Assume service life is 5 years and a rate of return of 4%.

16. 16 CEE 763 Fall 2011 16 PRIORITIZE PROJECTS l Project prioritization l Ranking by economic effectiveness measures l Incremental benefit-cost analysis l Optimization methods

17. 17 CEE 763 Fall 2011 17 SAFETY EFFECTIVENESS EVALUATION l Evaluation of the actual effectiveness l Observational Before-after studies