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Interactive Highway Safety Design Model (IHSDM): Overview

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. Results of the IHSDM support decisionmaking 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 five evaluation modules (i.e., Crash Prediction, Design Consistency, Policy Review, Traffic Analysis, and Driver/Vehicle), as well as an Economic Analyses Tool. This website provides a link to download the software, 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 – Highway Safety Manual (HSM) Predictive Method 2021 Release (version 17.0.0, September 2021)

The IHSDM – HSM Predictive Method 2021 Release (version 17.0.0, September 2021) may be downloaded free of charge via the Software Download page. 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

Development of the IHSDM was coordinated with the HSM, which was developed by the Transportation Research Board and the American Association of State Highway and Transportation Officials (AASHTO), and was also published by AASHTO.

FHWA’s Future Plans for IHSDM

FHWA will no longer carry out IHSDM software development. However, it will continue to support IHSDM and HSM users in a variety of ways. Click here for information about FHWA’s future plans for IHSDM, including:

  • IHSDM technical support.
  • FHWA’s IHSDM-related activities beyond the 2021 Release.
  • IHSDM 2021 – Crash Prediction Module (CPM) capabilities.
  • Future IHSDM software maintenance.
  • Future HSM-related activities.

IHSDM User Group Meetings

FHWA hosted an IHSDM User Group web meeting on December 6, 2023. A recording of the meeting is available here ; enter 2*52t?cn as the Passcode when prompted.

The meeting focused on IHSDM user applications, featuring a presentation by AtkinsRealis staff highlighting their IHSDM Project Applications:

  • Modeling Process Overview.
  • Case Studies: I-285 Eastside Project - Dekalb County, Georgia; I-15 Improvement Project, Las Vegas, Nevada; IH 45 Program, Bryan District, Texas; and FM 917 Schematic Design, Johnson County, Texas.
  • Lessons Learned.

Additional topics included: Review of IHSDM version 17 capabilities; Download and installation of IHSDM version 17; IHSDM website; FHWA’s plans for assisting IHSDM users in applying future Highway Safety Manual second edition (HSM2) Part C Predictive Methods; FHWA’s future plans for IHSDM; Future of IHSDM user group; and Training opportunities.

For more information on the IHSDM User Group, visit the User Group page.

On October 18, 2021 FHWA hosted a Data-Driven Safety Analysis (DDSA) webinar on IHSDM 2021 - New Intersection Models Support DDSA. A recording of the webinar is available here.


The Federal Highway Administration (FHWA) recently acquired the .gov domain for the Interactive Highway Safety Design Model (IHSDM) program. Although FHWA used to be associated with the domain name, it was recently purchased by another entity unrelated to FHWA. As such, FHWA is no longer affiliated with the .org site and thus not associated with any content that appears on the .org domain name. 

Check Out the Latest IHSDM Videos

IHSDM Part 1: Capabilities and Navigation


IHSDM Part 2: Data Entry


IHSDM Part 3: Crash Prediction Module and Economic Analysis Tool