U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

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Federal Highway Administration Research and Technology
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Interactive Highway Safety Design Model (IHSDM): Modules


The IHSDM suite of software analysis tools includes six evaluation modules:

  • Crash Prediction Module: Estimates the expected frequency of crashes on a highway using geometric design and traffic characteristics.
  • Design Consistency Module: Estimates the magnitude of potential speed inconsistencies to help identify and diagnose safety concerns at horizontal curves.
  • Intersection Review Module: Performs a diagnostic review to evaluate an intersection design for typical safety concerns.
  • Policy Review Module: Checks highway segment design elements relative to design policy.
  • Traffic Analysis Module: Estimates operational quality-of-service measures for a highway under current or projected future traffic flows.
  • Driver/Vehicle Module: Estimates a driver’s speed and path along a highway and corresponding measures of vehicle dynamics.


The IHSDM – HSM Predictive Method 2013 Release Crash Prediction Module includes capabilities to evaluate rural two-lane highways, rural multilane highways, urban/suburban arterials, freeway segments, and (new for the 2013 Release) freeway ramps/interchanges (including ramps, collector-distributor (C-D) roads, and ramp terminals). The other evaluation modules are only applicable to rural two-lane highways.

For additional information contact:

Shyuan-Ren (Clayton) Chen
Office of Safety Research & Development (HRDS)
Turner-Fairbank Highway Research Center
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101

Go to the Crash Prediction Module. Go to the Traffic Analysis Module. Go to the Policy Review Module. Go to the Driver/Vehicle Module. Go to the Design Consistency Module. Go to the Intersection Diagnostic Review Module.


Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101