The Federal Highway Administration (FHWA) has announced the release of the 2003 version of the Interactive Highway Safety Design Model (IHSDM), a new computer software program to help improve safety by providing state and local transportation officials with better information on the effects of design decisions they make for two-lane rural roads.
Forty-one percent of fatal crashes in the U.S. occur on undivided two-lane rural roads. In 2001, an estimated 17,000 traffic fatality occurred on these roads. Transportation planners can use IHSDM to estimate the frequency and severity of crashes on specific highway segments or measure expected car speed at various points along a road based on design and driver behavior patterns.
In the 2003 version of the software, planners can evaluate the safety of two-lane rural highways through five modules:
* Policy review--To ensure roadway design elements, such as cross section, lane and curve design, are in compliance with guidelines;
* Crash prediction--To estimate the number and severity of crashes on specified roadway segments;
* Design consistency--To assess driver speed behavior in relation to specific design features;
* Intersection review--To identify potential safety concerns in intersection geometric design and suggest possible remedies; and
* Traffic analysis--To evaluate roadway traffic operators under current or projects traffic loads through simulation.
To encourage the use of IHSDM, the FHWA incorporated mechanisms to exchange IHSDM-related data with commercial roadway design software used by highway agencies and their design consultants.
This version of the IHSDM is a product of the FHWA's Safety Research and Development Program at the Turner-Fairbank Highway Research Center, culminating a multi-year research and development effort.
The 2003 release of the IHSDM software can be downloaded at www.tfhrc.gov/safety/ihsdm/ihsdm.htm.