A Study of the Capacity Drop Phenomenon at Time-Dependent and Time-Independent Bottlenecks

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dc.contributor.authorEl-Metwally, Mahaen
dc.contributor.committeechairRakha, Hesham A.en
dc.contributor.committeememberEl-Shawarby, Ihaben
dc.contributor.committeememberHobeika, Antoine G.en
dc.contributor.departmentCivil Engineeringen
dc.date.accessioned2017-04-04T19:50:19Zen
dc.date.adate2011-01-12en
dc.date.available2017-04-04T19:50:19Zen
dc.date.issued2010-12-06en
dc.date.rdate2016-09-27en
dc.date.sdate2010-12-17en
dc.description.abstractThe fact that traffic congestion upstream of a bottleneck causes a reduction in the discharge flow rate through the bottleneck has been well documented in several empirical studies. However, what has been missing is an understanding of the causes of these empirically observed flow reductions. An identification of these causes is important in order to develop various mitigation schemes through the use of emerging technology. The concept of capacity drop can be introduced at time-independent bottlenecks (e.g. freeways) as well as time-dependent bottlenecks (e.g. signalized intersections). While to the author's knowledge no one has attempted to link these phenomena, the research presented in this thesis serves as a first step in doing so. The research uses the INTEGRATION simulation software, after demonstrating its validity against empirical data, to simulate time-independent and time-dependent bottlenecks in an attempt to characterize and understand the contributing factors to these flow reductions. Initially, the INTEGRATION simulation software is validated by comparing its results to empirically observed traffic stream behavior. This thesis demonstrates that the discharge flow rate is reduced at stationary bottlenecks at the onset of congestion. These reductions at stationary bottlenecks are not recovered as the traffic stream propagates downstream. Furthermore, these reductions are not impacted by the level of vehicle acceleration. Alternatively, the drop in the discharge flow rate caused by time-dependent bottleneck is recoverable and is dependent on the level of acceleration. The difference in behavior is attributed to the fact that in the case of a stationary bottleneck the delay in vehicle headways exceeds the losses caused by vehicle accelerations and thus is not recoverable. In the case of vehicles discharging from a backward recovery wave the dominant factor is the delay caused by vehicle acceleration and this can be recuperated as the traffic stream travels downstream.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12172010-131604en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12172010-131604/en
dc.identifier.urihttp://hdl.handle.net/10919/76921en
dc.language.isoen_USen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectTime-dependent Bottlenecksen
dc.subjectOnset of Congestionen
dc.subjectCapacity Dropen
dc.subjectTime-independent Bottlenecksen
dc.titleA Study of the Capacity Drop Phenomenon at Time-Dependent and Time-Independent Bottlenecksen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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