U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Scale and Scope of Safety Assessment Methods in the Project Development Process
Long Description
Predicted Average Crash Frequency for single-Vehicle Crash types is calculated as:
- Predicted average single-Vehicle crash frequency of a C-D road segment with base conditions, one lane, and fatal and injury severity equals the product of 0.5 and the exponential of -2.848 plus the product of 0.718 and the natural log of the product of 0.001 and 9800. (HSM Equation 19-26, p. 19-34 with urban one-lane C-D road segment FI crash severity constants from HSM Table 19-10, p. 19-35.)
- Predicted average single-Vehicle crash frequency of a C-D road segment with base conditions, one lane, and fatal and injury severity equals 0.149 crashes per year. (Approximately 0.149 FI single-vehicle crashes)
- Predicted average single-Vehicle crash frequency of a C-D road segment with base conditions, one lane, and property damage only equals the product of 0.5 and the exponential of -2.659 plus the product of 0.689 and the natural log of the product of 0.001 and 9800. (HSM Equation 19-26, p. 19-34 with urban one-lane C-D road segment PDO crash severity constants from HSM Table 19-10, p. 19-35.)
- Predicted average single -Vehicle crash frequency of a C-D road segment with base conditions, one lane, and property damage only equals 0.169 crashes per year. (Approximately 0.169 PDO single-vehicle crashes).
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Page last modified on November 18, 2016