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FHWA Releases 2013 Version of Interactive Highway Safety Design Model


IHDM Logo On September 30, 2013, the Federal Highway Administration (FHWA) released version 9.0.0 of the Interactive Highway Safety Design Model (IHSDM), a suite of software analysis tools for evaluating safety and operational effects of geometric design decisions. The new version includes a Crash Prediction Module (CPM) that provides a faithful implementation of the American Association of State Highway and Transportation Officials Highway Safety Manual (HSM), Part C: Predictive Method. It includes a beta version of crash prediction capabilities for freeway ramps, collector-distributor (C-D) roads, and ramp terminals, which are based on draft HSM materials developed under National Cooperative Highway Research Project 17-45. The CPM also covers two-lane rural highways, multilane rural highways, urban and suburban arterials, and freeway segments. Another highlight of the CPM is the Calibration Utility, which was developed after 2011 and has been added to the IHSDM Administration Tool (Admin Tool). The Calibration Utility, intended to assist agencies in implementing calibration procedures described in the Appendix to Part C of HSM, features step-by-step instructions and hands-on exercises illustrated in a tutorial lesson. IHSDM includes five other evaluation modules applicable to rural two-lane highways: policy review, design consistency, intersection review, traffic analysis, and driver/vehicle.

The software is available for free download at For more information, please contact Clayton Chen, 202-493-3054,