| Abstract: | One major gap in transportation system safety management is the ability to assess the safety ramifications of design changes for both new road projects and modifications to existing roads. To fulfill this need, the Federal Highway Administration (FHWA) and its many partners are developing a safety forecasting tool, the Interactive Highway Safety Design Model (IHSDM). The tool will be used by roadway design engineers, safety analysts, and planners throughout the United States. As such, the statistical models embedded in IHSDM will need to be able to forecast safety impacts under a wide range of roadway configurations and environmental conditions for a wide range of driver populations and will need to be able to capture elements of driving risk across states. One of the IHSDM algorithms developed by FHWA and its contractors is for forecasting accidents on rural road segments and rural intersections. The methodological approach is to use predictive models for specific base conditions, with traffic volume information as the sole explanatory variable for crashes, and then to apply regional or state calibration factors and accident modification factors (AMFs) to estimate the impact on accidents of geometric characteristics that differ from the base model conditions. In the majority of past approaches, AMFs are derived from parameter estimates associated with the explanatory variables. A recent study for FHWA used a multistate database to examine in detail the use of the algorithm with the base model-AMF approach and explored alternative base model forms as well as the use of full models that included nontraffic-related variables and other approaches to estimate AMFs. That research effort is reported. The results support the IHSDM methodology. |
| Supplemental Notes: |
This paper appears in Transportation Research Record No. 1840, Statistical Methods and Modeling and Safety Data, Analysis, and Evaluation. |
| TRIS Files: |
HRIS |
| Pagination: |
p. 78-86 |
| Authors: |
Lyon, C ; Oh, J ; Persaud, B ; Washington, S ; Bared, J |
| Features: |
References (7); Tables (9) |
| Monograph Info: |
See related components
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| Corporate Authors: |
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| Availability: |
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| ISBN: |
0309085810 |
| Publication Date: |
2003 |
| Serial: |
Transportation Research Record
Issue Number: 1840
Publisher:
Transportation Research Board
ISSN: 0361-1981
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| Index Terms: |
Algorithms; Forecasting; Intersections; Mathematical models; Rural areas; Traffic accidents; Interactive Highway Safety Design Model; Accident modification factors |
| Subject Areas: |
Highways
Safety and Human Factors
I81: Accident Statistics
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