Home
Feedback
Federal Highway Administration (FHWA), Safety Design Division (HSR-20) Turner-Fairbank Highway Research Center
SUMMARY:
IHSDM is a major, multi-year, $8-10M program, under the direction of the FHWA Safety Design Division (HSR-20). The goal of the IHSDM research program is to develop a systematic approach that will enable roadway designers and design reviewers to assess the potential safety effects of specific geometric design decisions. The IHSDM is envisioned as a series of interactive computer programs (modules) integrated into and accessed from commercially-available CAD/Roadway Design packages.
Potential users (State DOTs, consulting engineers, etc.) will be active participants in the development of the model, and widespread use of IHSDM is expected as the software is incorporated into the roadway design process. IHSDM will facilitate decision-making from the planning through final design stages. The model will be applicable for both new construction and reconstruction projects.
The FHWA has established a Technical Working Group which consists of representatives from several State DOTs and FHWA field offices. The primary function of the group is to provide guidance on the type of information and the format in which the information, from IHSDM, should be presented to the user.
IHSDM is an evolving concept -- current thinking is that IHSDM will be composed of six modules: (1) Vehicle Dynamics Module (VDM); (2) Design Consistency Module (DCM); (3) Accident Analysis Module (AAM); (4) Driver Performance Module (DPM); (5) Policy Review Module (PRM); and (6) Traffic Assessment Module (TAM).
Several independent research studies are underway to develop the IHSDM modules, which are at different stages of development. FHWA's Geometric Design Laboratory (GDL) will be responsible for integrating the IHSDM modules into a single model. Designers (users) will have the option of running the modules stand-alone or as part of the integrated IHSDM model.
A summary of the six modules is as follows:
The DCM provides a measure of the consistency of a design, in terms of satisfying driver expectation. A vehicle speed profile (85th percentile operating speeds) and/or a driver workload profile can be generated for a design. Graphical “flags” will warn the user of design inconsistencies.
The AAM will allow the user to both qualitatively and quantitatively assess the safety impacts of design decisions. Separate roadway and roadside accident prediction models are envisioned, along with an “expert system” (diagnostic review) approach. Output will include the expected number of accidents for a roadway segment and expected severity of accidents.
The DPM will provide feedback on driver behavior based on roadway geometry. Using a virtual reality approach the designer will be able to "drive" through a three-dimensional image of the design. Development of a DPM will be a complex and long-range effort.
The PRM will identify design elements that are not in compliance with established design criteria (such as the AASHTO “Green Book”) and "flag" these elements for review by the designer.
The TAM will allow the designer to examine the design under full traffic conditions, using computer traffic simulation programs. It will provide data on vehicle operations to help establish accident-ADT-geometrics relationships.
To receive more information regarding IHSDM, contact Mr. Justin True or Mr. Mike Dimaiuta at the addresses listed below:
Tel. (703)-285-2121
Fax (703)-285-2679
E-mail: justin.true@fhwa.dot.gov
========================
Mr. Mike Dimaiuta
Program Manager - Geometric Design Laboratory
A/E Group, Inc., c/o FHWA
6300 Georgetown Pike
MS HSR-20
McLean, VA 22101
Tel. (703)-285-2189
Fax (703)-285-2679
E-mail: mike.dimaiuta@fhwa.dot.gov
|
Home |
Feedback |