1. PIARC TC C.2.3: Cost-Effectiveness of Safety Measures and Allocation of Resources State of Michigan Time of Return Safety Calculation Larry E. Tibbits Michigan Department of Transportation Kuala Lumpur, Malaysia

2. Time of Return (TOR) It is one type of cost benefit tool Estimates benefits (reducing crashes/injuries/deaths) Output: the number of years required to recover the safety investment Based upon Roy Jorgensen’s report on Highway Safety Improvement Criteria

3. Why Use TOR Federal Highway Safety Improvement Program requires that we invest safety dollars where they are needed most – where we get the greatest return Helps prioritize competing safety projects Verifies how the safety fix matches the demonstrated safety problem

4. Crash Data Crash type Number of crashes Property damage only + minor injury (B, C) Number of A injuries or number killed (people) Each incident is one crash

5. TOR Components Estimated costs of deaths and injuries from U.S. National Safety Council (http://www.nsc.org/) Estimated benefits resulting from reducing crashes Traffic volumes Reduction in fatalities and A injuries combined Reduction in minor (no A injuries or fatalities) crashes

6. TOR Components Q factor to blend the impact of fatalities and A injuries Estimated project costs Number of years of crash data used (3-5) Area Factor - Urban, rural, and between

7. The Calculation Roy Jorgensen's Formula BTOTAL = ADTa/ADTbx/ (QxR1+(PDOCOSTxR2)) BTOTAL = Total benefit in dollars over years used ADTa = Average traffic volume after the improvement (assumed) ADTb = Average traffic volume before the improvement

8. The Calculation (Continued) R1 = Reduction in fatalities and A- injuries combined R2 = Reduction in minor (no A- injuries or fatalities) crashes Q = [FATCOST+((I/FxINJCOST]/1+(I/F]

9. Thank You http://www.michigan.gov/tands