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

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 provide...

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محفوظ في:
التفاصيل البيبلوغرافية
المؤلف الرئيسي: El Khoury, John (author)
التنسيق: masterThesis
منشور في: 2005
الوصول للمادة أونلاين:http://hdl.handle.net/10725/6730
http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php
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author El Khoury, John
author_facet El Khoury, John
author_role author
dc.creator.none.fl_str_mv El Khoury, John
dc.date.none.fl_str_mv 2005
2017-12-07T11:26:56Z
2017-12-07T11:26:56Z
2017-12-07
dc.identifier.none.fl_str_mv http://hdl.handle.net/10725/6730
El Khoury, J. (2005). Accounting for risk and level of service in the design of passing sight distances (Doctoral dissertation).
http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php
dc.language.none.fl_str_mv en
dc.publisher.none.fl_str_mv Virginia Polytechnic Institute and State University
dc.rights.*.fl_str_mv info:eu-repo/semantics/openAccess
dc.title.none.fl_str_mv Accounting for risk and level of service in the design of passing sight distances
dc.type.none.fl_str_mv Thesis
info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/masterThesis
description 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.
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spelling Accounting for risk and level of service in the design of passing sight distancesEl Khoury, JohnCurrent 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.N/Axii, 142 p: illIncludes bibliographical referencesVirginia Polytechnic Institute and State University2017-12-07T11:26:56Z2017-12-07T11:26:56Z20052017-12-07Thesisinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesishttp://hdl.handle.net/10725/6730El Khoury, J. (2005). Accounting for risk and level of service in the design of passing sight distances (Doctoral dissertation).http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.phpeninfo:eu-repo/semantics/openAccessoai:laur.lau.edu.lb:10725/67302021-03-19T10:43:18Z
spellingShingle Accounting for risk and level of service in the design of passing sight distances
El Khoury, John
status_str publishedVersion
title Accounting for risk and level of service in the design of passing sight distances
title_full Accounting for risk and level of service in the design of passing sight distances
title_fullStr Accounting for risk and level of service in the design of passing sight distances
title_full_unstemmed Accounting for risk and level of service in the design of passing sight distances
title_short Accounting for risk and level of service in the design of passing sight distances
title_sort Accounting for risk and level of service in the design of passing sight distances
url http://hdl.handle.net/10725/6730
http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php