New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation
Publication: Journal of Transportation Engineering, Part A: Systems
Volume 144, Issue 4
Abstract
Road crashes are mainly caused by three concurrent factors: infrastructure, vehicles, and human factors. The interaction between infrastructure and human factors leads to the concept of geometric design consistency, which can be defined as how drivers’ expectations and road behavior fit. This paper presents a new global consistency model based on the difference between the inertial operating speed profile () and the operating speed profile (). The first is calculated as the weighted average speed of the previous road section and represents drivers’ expectations, whereas the second represents road behavior. A set of 71 homogeneous two-lane rural road segments located in Italy were used in the calibration of the model. As a result, a safety performance function based on this new consistency model was proposed to estimate the number of crashes on an entire road segment. Finally, the new model was compared with previous global consistency models, concluding that the new consistency parameter better explains the phenomenon than the previous ones. Therefore, the new consistency model is a useful tool for engineers that allows estimation of the number of crashes and incorporates road safety into the geometric design of both new two-lane rural roads and improvements to existing highways.
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Acknowledgments
This research was subsidized by the Spanish Ministry of Economy and Competitiveness through “Ayudas a la movilidad predoctoral para la realización de estancias breves en centros de I+D 2015.” The study presented in this paper is also part of the research project titled “CASEFU—Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales” (TRA2013-42578-P), subsidized by the Spanish Ministry of Economy and Competitiveness and the European Social Fund. In addition, the authors would like to thank the Azienda Nazionale Autonoma delle Strade (ANAS) and the Automobile Club Italia (ACI), which provided traffic and crash data, respectively.
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Published In
Journal of Transportation Engineering, Part A: Systems
Volume 144 • Issue 4 • April 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: May 23, 2017
Accepted: Sep 22, 2017
Published online: Jan 18, 2018
Published in print: Apr 1, 2018
Discussion open until: Jun 18, 2018
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