Free-gap evaluation for two-lane rural highways
Autor(a) principal: | |
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Data de Publicação: | 2011 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | https://repositorio-aberto.up.pt/handle/10216/85061 |
Resumo: | Studies related to operating speed predicting models' development require vehicles' speed under free-flow conditions to be collected at different sites. Thus, a critical issue is the definition of the gap (or headway) from which the speed of one vehicle is not affected by the speed of the vehicle ahead. In many studies, a 5-s headway was adopted as the reference headway value from which a vehicle could be assumed to travel at a free-flow speed. Justifications for this value's application are not clearly presented in the literature, and some authors suggest the use of other reference values. This paper presents a definition for platoon from observed values of vehicles' time gap. The reference gap value between two successive vehicles considered as traveling in a nonplatoon condition is defined as "free gap." A five-step methodology is described and tested for road conditions in Portugal. The application performed showed both the adequacy of the methodology proposed and the convenience of exploratory studies aimed at the identification of platoon gap (or headway) suitable for specific operating speed studies. According to the methodology proposed, a 6-s gap is a suitable reference for future data collection on operating speed on Portuguese roads. This result suggests the need to review the headway reference values found in the literature for representing free-flow general conditions. |
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Free-gap evaluation for two-lane rural highwaysEngenharia de infra-estruturas, Engenharia civilInfrastructures engineering, Civil engineeringStudies related to operating speed predicting models' development require vehicles' speed under free-flow conditions to be collected at different sites. Thus, a critical issue is the definition of the gap (or headway) from which the speed of one vehicle is not affected by the speed of the vehicle ahead. In many studies, a 5-s headway was adopted as the reference headway value from which a vehicle could be assumed to travel at a free-flow speed. Justifications for this value's application are not clearly presented in the literature, and some authors suggest the use of other reference values. This paper presents a definition for platoon from observed values of vehicles' time gap. The reference gap value between two successive vehicles considered as traveling in a nonplatoon condition is defined as "free gap." A five-step methodology is described and tested for road conditions in Portugal. The application performed showed both the adequacy of the methodology proposed and the convenience of exploratory studies aimed at the identification of platoon gap (or headway) suitable for specific operating speed studies. According to the methodology proposed, a 6-s gap is a suitable reference for future data collection on operating speed on Portuguese roads. This result suggests the need to review the headway reference values found in the literature for representing free-flow general conditions.20112011-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttps://repositorio-aberto.up.pt/handle/10216/85061eng0361-198110.3141/2223-02António LoboMaria Alice Prudêncio JacquesCarlos Manuel RodriguesAntónio Coutoinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-11-29T14:46:47Zoai:repositorio-aberto.up.pt:10216/85061Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T00:08:16.753954Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Free-gap evaluation for two-lane rural highways |
title |
Free-gap evaluation for two-lane rural highways |
spellingShingle |
Free-gap evaluation for two-lane rural highways António Lobo Engenharia de infra-estruturas, Engenharia civil Infrastructures engineering, Civil engineering |
title_short |
Free-gap evaluation for two-lane rural highways |
title_full |
Free-gap evaluation for two-lane rural highways |
title_fullStr |
Free-gap evaluation for two-lane rural highways |
title_full_unstemmed |
Free-gap evaluation for two-lane rural highways |
title_sort |
Free-gap evaluation for two-lane rural highways |
author |
António Lobo |
author_facet |
António Lobo Maria Alice Prudêncio Jacques Carlos Manuel Rodrigues António Couto |
author_role |
author |
author2 |
Maria Alice Prudêncio Jacques Carlos Manuel Rodrigues António Couto |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
António Lobo Maria Alice Prudêncio Jacques Carlos Manuel Rodrigues António Couto |
dc.subject.por.fl_str_mv |
Engenharia de infra-estruturas, Engenharia civil Infrastructures engineering, Civil engineering |
topic |
Engenharia de infra-estruturas, Engenharia civil Infrastructures engineering, Civil engineering |
description |
Studies related to operating speed predicting models' development require vehicles' speed under free-flow conditions to be collected at different sites. Thus, a critical issue is the definition of the gap (or headway) from which the speed of one vehicle is not affected by the speed of the vehicle ahead. In many studies, a 5-s headway was adopted as the reference headway value from which a vehicle could be assumed to travel at a free-flow speed. Justifications for this value's application are not clearly presented in the literature, and some authors suggest the use of other reference values. This paper presents a definition for platoon from observed values of vehicles' time gap. The reference gap value between two successive vehicles considered as traveling in a nonplatoon condition is defined as "free gap." A five-step methodology is described and tested for road conditions in Portugal. The application performed showed both the adequacy of the methodology proposed and the convenience of exploratory studies aimed at the identification of platoon gap (or headway) suitable for specific operating speed studies. According to the methodology proposed, a 6-s gap is a suitable reference for future data collection on operating speed on Portuguese roads. This result suggests the need to review the headway reference values found in the literature for representing free-flow general conditions. |
publishDate |
2011 |
dc.date.none.fl_str_mv |
2011 2011-01-01T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://repositorio-aberto.up.pt/handle/10216/85061 |
url |
https://repositorio-aberto.up.pt/handle/10216/85061 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
0361-1981 10.3141/2223-02 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
|
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1799136007981891585 |