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
CMF for horizontal curve is calculated as (HSM equation 19-33, p.19-47):
- The crash modification factor for horizontal curvature on a site of type w, cross section x, crash type y, and severity z equals 1.0 plus the product of a and 1000 divided by 32.2 and the following calculation for the each of the number of curves:
- The square of the average entry speed at the curve divided by the radius of the curve multiplied by the proportion of segment length with the curve.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, multi-vehicle, and fatal and injury severity equals 1.0 plus the product of 0.779 and 1000 divided by 32.2 and the square of 95.55 divided by 11460 multiplied by 0.04 divided by 0.5 plus the square of 88.37 divided by 150 multiplied by 0.12 divided by 0.5.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, multi-vehicle, and fatal and injury severity equals 3.015.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, multi-vehicle, and property damage only severity equals 1.0 plus the product of 0.545 and 1000 divided by 32.2 and the square of 95.55 divided by 11460 multiplied by 0.04 divided by 0.5 plus the square of 88.37 divided by 150 multiplied by 0.12 divided by 0.5.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, multi-vehicle, and property damage only severity equals 2.410.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, single-vehicle, and fatal and injury severity equals 1.0 plus the product of 2.406 and 1000 divided by 32.2 and the square of 95.55 divided by 11460 multiplied by 0.04 divided by 0.5 plus the square of 88.37 divided by 150 multiplied by 0.12 divided by 0.5.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, single-vehicle, and fatal and injury severity equals 7.224.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, single-vehicle, and property damage only severity equals 1.0 plus the product of 3.136 and 1000 divided by 32.2 and the square of 95.55 divided by 11460 multiplied by 0.04 divided by 0.5 plus the square of 88.37 divided by 150 multiplied by 0.12 divided by 0.5.
- The crash modification factor for horizontal curvature of a C-D road segment with base conditions, one lane, single-vehicle, and property damage only severity equals 9.113.
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Page last modified on November 18, 2016