Access Control Design on Highway Interchanges

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dc.contributorVirginia Tech Transportation Instituteen
dc.contributorVirginia Techen
dc.contributor.authorRakha, Hesham A.en
dc.contributor.authorFlintsch, Alejandra Medinaen
dc.contributor.authorArafeh, Mazenen
dc.contributor.authorAbdel-Salam, Abdel-Salam Gomaaen
dc.contributor.authorDua, Dhruven
dc.contributor.authorAbbas, Montasir M.en
dc.contributor.departmentCivil and Environmental Engineeringen
dc.date.accessed2013-11-21en
dc.date.accessioned2014-03-19T18:30:13Zen
dc.date.available2014-03-19T18:30:13Zen
dc.date.issued2008-01-01en
dc.description.abstractThe adequate spacing and design of access to crossroads in the vicinity of freeway ramps are critical to the safety and traffic operations of both the freeway and the crossroad. The research presented in this report develops a methodology to evaluate the safety impact of different access road spacing standards. The results clearly demonstrate the shortcomings of the AASHTO standards and the benefits of enhancing them. The models developed as part of this research were used to compute the crash rate associated with alternative section spacing. The study demonstrates that the models satisfied the statistical requirements and provide reasonable crash estimates. The results demonstrate an eight-fold decrease in the crash rate when the access road spacing increases from 0 to 300 m. An increase in the minimum spacing from 90 m (300 ft) to 180 m (600 ft) results in a 50 percent reduction in the crash rate. The models were used to develop lookup tables that quantify the impact of access road spacing on the expected number of crashes per unit distance. The tables demonstrate a decrease in the crash rate as the access road spacing increases. An attempt was made to quantify the safety cost of alternative access road spacing using a weighted average crash cost. The weighted average crash cost was computed considering that 0.6, 34.8, and 64.6 percent of the crashes were fatal, injury, and property damage crashes, respectively. These proportions were generated from the field observed data. The cost of each of these crashes was provided by VDOT as $3,760,000, $48,200, and $6,500 for fatal, injury, and property damage crashes, respectively. This provided an average weighted crash cost of $43,533. This average cost was multiplied by the number of crashes per mile to compute the cost associated with different access spacing scenarios. These costs can assist policy makers in quantifying the trade-offs of different access management regulations.en
dc.description.sponsorshipVirginia Department of Transportation 80596en
dc.format.extent79 pagesen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationHesham Rakha, Alejandra Medina Flintsch, Mazen Arafeh, Abdel-Salam Gomaa Abdel-Salam, Dhruv Dua, and Montassir Abbas. "Access Control Design on Highway Interchanges," Virginia Transportation Research Council 530 Edgemont Road Charlottesville, VA 22903, Report No. VTRC 08-CR7, Jan. 2008.en
dc.identifier.govdocVTRC 08-CR7en
dc.identifier.urihttp://hdl.handle.net/10919/46669en
dc.identifier.urlhttp://www.virginiadot.org/vtrc/main/online_reports/pdf/08-CR7.pdfen
dc.language.isoenen
dc.publisherVirginia Center for Transportation Innovation and Researchen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectAccess managementen
dc.subjectAccess breaks at interchangesen
dc.subjectAccess distances from interchangesen
dc.subjectSafety at interchangesen
dc.subjectAccidents at interchangesen
dc.subjectSafety and accidents for accessen
dc.subjectDistances from interchangeen
dc.titleAccess Control Design on Highway Interchangesen
dc.typeTechnical reporten
dc.type.dcmitypeTexten

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