IHSDM is a suite of software analysis tools for evaluating safety and operational effects of geometric design on highways. The IHSDM–HSM Predictive Method 2021 Release includes five evaluation modules: Crash Prediction, Policy Review, Design Consistency, Traffic Analysis and Driver/Vehicle Modules. The CPM includes a faithful implementation of Part C (Predictive Method) of the HSM for rural two-lane highways (HSM Chapter 10), multilane rural highways (HSM Chapter 11), urban and suburban arterials (HSM Chapter 12), freeways (HSM Chapter 18) and ramps/interchanges (HSM Chapter 19). In addition, the CPM includes predictive methods developed for the future 2nd Edition HSM (HSM2) six-or-more lane urban/suburban arterials (based on methods developed under NCHRP Project 17-58 (Safety Prediction Models for Six-Lane and One-Way Urban and Suburban Arterials), roundabouts (based on methods developed under NCHRP Project 17-70 (Development of Roundabout Crash Prediction Models and Methods), and some intersection types not covered in the HSM (based on methods developed under NCHRP Project 17-68 (Intersection Crash Prediction Methods for the Highway Safety Manual). The PRM is applicable to rural two-lane and rural multilane highways. The other IHSDM evaluation modules are applicable to rural two-lane highways.

In addition, IHSDM includes an Economic Analyses Tool (EA Tool), which allows users to conduct economic analyses within IHSDM, using CPM evaluation results (crash frequencies and severities). The IHSDM Economic Analyses Tool Help pdf and an IHSDM Economic Analyses Tool Tutorial Lesson pdf are available with the software to help you get started.

The IHSDM Help Browser (accessed via Help > Help Browser from the IHSDM main menu) and the IHSDM Tutorial (accessed via Help > Tutorial from the IHSDM main menu) are excellent resources to get started with IHSDM.

IHSDM “How-To” videos are also provided on the IHSDM: Overview webpage.

For a general overview of IHSDM, the best starting point is the main IHSDM web site, Interactive Highway Safety Design Model (IHSDM): Overview.

After successfully installing the IHSDM, we suggest that you start by reviewing the IHSDM Tutorial, which can be found under 'Help' in the main menu. 

Open the Help Browser (from the main menu "Help/Help Browser") and read through the "Release Notes for 2021 Public Release."

You may install the 2021 Release over the 2020 Release, 2019 Release, 2018 Release Update, 2018 Release, 2017 Release Update, 2017 Release, 2016 Release Update, 2016 Release, 2015 Release Update, 2015 Release, 2014 Release Update, 2014 Release, 2013 Release, 2012 Release or 2011 Release. You can archive your 2010/2009/2008 Release projects individually (via Project Operations > Archive Project), then un-archive them in the 2021 Release (via User Operations > Un-archive Project).