Development of Accident Modification Factors for Rural Frontage Road Segments in Texas Using Generalized Additive Models
Publication: Journal of Transportation Engineering
Volume 137, Issue 1
Abstract
The objective of this study consists of assessing the application of generalized additive models (GAMs) for estimating accident modification factors (AMFs). GAMs are a new type of models that have been recently introduced by the statistical community for modeling observed data. These models offer more flexible functional forms than traditional generalized linear models and allow for more adaptable variable interactions. As recently documented in the literature, variable interactions should be included in the development of AMFs. To accomplish the study objective, AMFs were derived from GAMs using data collected on rural frontage roads in Texas. The AMFs were then compared to the AMFs produced from a previous study using the same data set. The results of the study show that AMFs produced from GAMs are more flexible to characterize the safety effect of simultaneous changes in geometric and operational features (or variable interactions) than when independent AMFs are applied together. The results also show that GAMs indicated a nonlinear relationship between crash risk and changes in lane and shoulder widths for frontage roads in Texas.
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Acknowledgments
Although the study was not funded by TxDOT, the writers wish to thank Ms. Elizabeth Hilton from TxDOT and Dr. James A. Bonneson for providing the data. The data were initially collected for TxDOT Project 0-4703 led by Dr. Bonneson. The writers would like to thank the anonymous reviewers for providing useful comments aimed at improving this paper.
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Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 137 • Issue 1 • January 2011
Pages: 74 - 83
Copyright
© 2011 ASCE.
History
Received: Feb 25, 2009
Accepted: Jul 6, 2010
Published online: Dec 15, 2010
Published in print: Jan 2011
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