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Interactive Highway Safety Design Model (IHSDM): Overview

The Interactive Highway Safety Design Model (IHSDM) is a suite of software analysis tools used to evaluate the safety and operational effects of geometric design decisions on highways.

IHSDM is a decision-support tool that provides estimates of a highway design's expected safety and operational performance and checks existing or proposed highway designs against relevant design policy values. Results of the IHSDM support decision making in the highway design process. Intended users include highway project managers, designers, and traffic and safety reviewers in State and local highway agencies and in engineering consulting firms.

The IHSDM—which supports the Federal Highway Administration's (FHWA's) Data-Driven Safety Analysis (DDSA) initiative—includes six evaluation modules (Crash Prediction, Design Consistency, Intersection Review, Policy Review, Traffic Analysis, and Driver/Vehicle), as well as an Economic Analyses Tool. This website summarizes the capabilities and applications of the IHSDM evaluation modules, and provides a library of the research reports documenting their development.

Now Available: The IHSDM – HSM Predictive Method 2019 Release (version 15.0.0, October 2019)

The IHSDM  HSM Predictive Method 2019 Release (version 15.0.0, October 2019) may be downloaded free of charge (visit for details). User technical support is also available free of charge at and 202–493–3407. IHSDM-related training is offered by the FHWA Resource Center and through the FHWA’s National Highway Institute. Visit the IHSDM website for information about the IHSDM User Group and upcoming Events.

Development of the IHSDM is coordinated with two related initiatives: the Highway Safety Manual, developed by the Transportation Research Board and published by the American Association of State Highway and Transportation Officials (AASHTO), and Safety Analyst, developed by FHWA and now available as AASHTOWare.

Updated: Monday, December 2, 2019