Critical Gap as a Function of Waiting Time in Determining Roundabout Capacity

Polus, Abishai; Lazar, Sitvanit Shmueli; Livneh, Moshe

doi:10.1061/(asce)0733-947x(2003)129:5(504)

Cited by 74 publications

(30 citation statements)

References 5 publications

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“…Polus et Shmueli (1999) s'appuient sur l'utilisation d'un tel créneau critique pour modéliser la capacité d'un giratoire, mais ils soulignent que celui-ci dépend de plusieurs caractéristiques. Ils présentent, ainsi que Polus et al (2003), l'influence sur le créneau critique du temps d'attente à l'approche. En effet, il est supposé que l'impatience croissante du conducteur qui attend à l'entrée du carrefour giratoire provoque une diminution du créneau minimum que celui-ci considère comme acceptable pour entrer sur l'anneau.…”

Section: Prévision De La Capacitéunclassified

Dernières avancées sur les carrefours giratoires

Pellecuer

St-Jacques

2008

Can. J. Civ. Eng.

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Le carrefour giratoire est un aménagement routier qui a connu un fort succès au cours des années 1970 et est désormais pratique courante en Europe grâce à ses performances en termes de capacité et de sécurité. Néanmoins, ce concept d'ingénierie est d'usage beaucoup moins répandu dans le reste du monde et, notamment, en Amérique du Nord où la population reste circonspecte à son propos. Pourtant, lors de mises en application, les préjugés négatifs se transforment rapidement en opinion favorable. De plus, lorsque l'implantation est précédée d'une planification et d'une conception minutieuses, accompagnée d'une campagne de communication efficace, le carrefour giratoire peut être adapté à l'environnement et aux conducteurs nord-américains. De nombreux guides proposent un cadre pour la conception des carrefours giratoires, mais il n'existe pas encore de normes établies. Les efforts de recherche actuels visent à mieux comprendre le fonctionnement de ces aménagements routiers afin de pouvoir tirer des règles de conception plus efficaces et pertinentes. Abstract:A roundabout is a street design that experienced great success in the 1970s and is now common practice in Europe because of its performance in terms of capacity and safety. Nevertheless, this engineering design is much less used in the rest of the world, especially in North America, where the population is still reluctant to adopt it. However, when it is implemented, negative preconceptions are rapidly transformed to favourable opinions. Moreover, with careful planning and design, coupled with an efficient communication campaign, the roundabout can be adapted to the North American environment and drivers. Several guides propose a design framework for roundabouts, but there are no set standards. Current research efforts in understanding the operation of these street designs are aimed at establishing more relevant and effective design rules.

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Section: Prévision De La Capacitéunclassified

Dernières avancées sur les carrefours giratoires

Pellecuer

St-Jacques

2008

Can. J. Civ. Eng.

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“…Therefore, predicting the potential operating speed at a roundabout, during its design stage, is vital to ensure that the expected operating speed will meet the design expectations and the safety target for that roundabout. Furthermore, the capacity of a roundabout is highly correlated with critical time headways and follow-up times selected by drivers [5][6][7][8][9], which are related to the operating speed at the roundabout [2,[10][11][12][13][14]. Therefore, predicting the operating speed will also help in estimating the potential capacity of the roundabout being designed and ensure that the capacity meets the design requirements and the expected traffic volume.…”

Section: Introductionmentioning

confidence: 99%

Predicting Operating Speeds at Urban Multilane Roundabouts in Abu Dhabi, United Arab Emirates

Almoarawi

Dabbour

2018

Journal of Advanced Transportation

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There are more than 460 multilane roundabouts located in Abu Dhabi, the capital city of the United Arab Emirates, and its surrounding areas. Most of those roundabouts have three entry/circulatory/exit lanes with large radii, which resulted in the majority of drivers exceeding the speed limits for those roundabouts. Those excessive operating speeds, along with lack of drivers' awareness of the proper rules of driving at roundabouts, have resulted in increased collision frequencies at Abu Dhabi roundabouts. In this paper, operating speeds were measured at 12 roundabouts in Abu Dhabi and those collected speed observations were used to calibrate regression models to predict the 85th percentile operating speeds at roundabouts in Abu Dhabi. Predicting operating speed at a roundabout, during its design stage, is necessary to ensure that the expected operating speed and capacity will meet the design expectations. Three models were calibrated to predict the entry, circulating, and exit speeds, respectively. The calibrated models were validated with data not used in calibration and they were found to be stable and robust. The findings of this research study will help engineers when designing new roundabouts in Abu Dhabi or other cities with similar characteristics. This research study also provides a methodological framework for other researchers when conducting similar speed studies for roundabouts in other cities or metropolitan areas around the world.

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“…[1][2][3][4][5][6]. Many researchers dealt with gap acceptance at unsignalized intersections with the assumption that priority is fully respected, such as Hawkes [7], Ashworth [8,9], Ashton [10], Miller [11], Polus et al [12], Davis and Swenson [13], Xu and Tian [14].…”

Section: Introductionmentioning

confidence: 99%

Adaptive neuro-fuzzy interface system for gap acceptance behavior of right-turning vehicles at partially controlled T-intersections

Sangole

Patil

2014

J. Mod. Transport.

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Gap acceptance theory is broadly used for evaluating unsignalized intersections in developed countries. Intersections with no specific priority to any movement, known as uncontrolled intersections, are common in India. Limited priority is observed at a few intersections, where priorities are perceived by drivers based on geometry, traffic volume, and speed on the approaches of intersection. Analyzing such intersections is complex because the overall traffic behavior is the result of drivers, vehicles, and traffic flow characteristics. Fuzzy theory has been widely used to analyze similar situations. This paper describes the application of adaptive neuro-fuzzy interface system (ANFIS) to the modeling of gap acceptance behavior of right-turning vehicles at limited priority T-intersections (in India, vehicles are driven on the left side of a road). Field data are collected using video cameras at four T-intersections having limited priority. The data extracted include gap/lag, subject vehicle type, conflicting vehicle type, and driver's decision (accepted/rejected). ANFIS models are developed by using 80 % of the extracted data (total data observations for major road rightturning vehicles are 722 and 1,066 for minor road rightturning vehicles) and remaining are used for model validation. Four different combinations of input variables are considered for major and minor road right turnings separately. Correct prediction by ANFIS models ranges from 75.17 % to 82.16 % for major road right turning and 87.20 % to 88.62 % for minor road right turning. The models developed in this paper can be used in the dynamic estimation of gap acceptance in traffic simulation models.

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Critical Gap as a Function of Waiting Time in Determining Roundabout Capacity

Cited by 74 publications

References 5 publications

Dernières avancées sur les carrefours giratoires

Dernières avancées sur les carrefours giratoires

Predicting Operating Speeds at Urban Multilane Roundabouts in Abu Dhabi, United Arab Emirates

Adaptive neuro-fuzzy interface system for gap acceptance behavior of right-turning vehicles at partially controlled T-intersections

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