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dc.contributor.authorEl Khoury, Johnen
dc.date.accessioned2014-03-14T20:19:24Zen
dc.date.available2014-03-14T20:19:24Zen
dc.date.issued2005-11-28en
dc.identifier.otheretd-11302005-182401en
dc.identifier.urihttp://hdl.handle.net/10919/29805en
dc.description.abstractCurrent 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 two-lane roads. Using the simulation results, the author is able to assess the risk of 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
dc.publisherVirginia Techen
dc.relation.haspartDissertation_khoury_4.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectpassing sight distanceen
dc.subjecttwo-lane roadsen
dc.subjectovertakingen
dc.subjectreliabilityen
dc.subjectrisk indexen
dc.subjectsafetyen
dc.subjectservice measuresen
dc.subjectSimulationen
dc.subjecttrade-off analysisen
dc.titleAccounting for Risk and Level of Service in the Design of Passing Sight Distancesen
dc.typeDissertationen
dc.contributor.departmentCivil Engineeringen
dc.description.degreePh. D.en
thesis.degree.namePh. D.en
thesis.degree.leveldoctoralen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineCivil Engineeringen
dc.contributor.committeechairHobeika, Antoine G.en
dc.contributor.committeememberTrani, Antoino A.en
dc.contributor.committeememberBaik, Hojongen
dc.contributor.committeememberRakha, Hesham A.en
dc.contributor.committeememberSpanos, Arisen
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11302005-182401/en
dc.date.sdate2005-11-30en
dc.date.rdate2007-12-07en
dc.date.adate2005-12-07en


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