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Accounting for risk and level of service in the design of passing sight distances

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dc.contributor.author El Khoury, John
dc.date.accessioned 2017-12-07T11:26:56Z
dc.date.available 2017-12-07T11:26:56Z
dc.date.copyright 2005 en_US
dc.identifier.uri http://hdl.handle.net/10725/6730
dc.description.abstract Current design methods in transportation engineering do not simultaneously address the levels of risk and service associated with the design and use of various highway geometric elements. Passing sight distance (PSD) is an example of a geometric element designed with no risk measures. PSD is provided to ensure the safety of passing maneuvers on two-lane roads. Many variables decide the minimum length required for a safe passing maneuver. These are random variables and represent a wide range of human and vehicle characteristics. Also, current PSD design practices replace these random variables by single-value means in the calculation process, disregarding their inherent variations. The research focuses on three main objectives. The first goal is to derive a PSD distribution that accounts for the variations in the contributing parameters. Two models are devised for this purpose, a Monte-Carlo simulation model and a closed form analytical estimation model. The results of both models verify each other and differ by less than 5 percent. Using the PSD distribution, the reliability index of the current PSD criteria are assessed. The second goal is to attach risk indices to the various PSD lengths of the obtained distribution. A unique microscopic simulation is devised to replicate passing maneuvers on twolane roads. Using the simulation results, the author is able to assess the risk o various PSD lengths for a specific design speed. The risk index of the AASHTO Green Book and the MUTCD PSD standards are also obtained using simulation. With risk measures attached to the PSD lengths, a trade-off analysis between the level of service and risk is feasible to accomplish. The last task is concerned with applying the Highway Capacity Manual concepts to assessing the service measures of the different PSD lengths. The results of the final trade-off analysis show that for a design speed of 50 mph, the AASHTO Green Book and the MUTCD standards overestimate the PSD requirements. The criteria can be reduced to 725 ft and still be within an acceptable risk level. en_US
dc.language.iso en en_US
dc.title Accounting for risk and level of service in the design of passing sight distances en_US
dc.type Thesis en_US
dc.author.degree PHD en_US
dc.author.school SOE en_US
dc.author.idnumber 200103005 en_US
dc.author.department Civil Engineering en_US
dc.description.embargo N/A en_US
dc.description.physdesc xii, 142 p: ill en_US
dc.description.bibliographiccitations Includes bibliographical references en_US
dc.identifier.ctation El Khoury, J. (2005). Accounting for risk and level of service in the design of passing sight distances (Doctoral dissertation). en_US
dc.author.email john.khoury@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php en_US
dc.publisher.institution Virginia Polytechnic Institute and State University en_US
dc.author.affiliation Lebanese American University en_US


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