Estimation of critical gap at small roundabout

Azhari, S. F.; Puan, Othman Che; Hassan, Sitti Asmah; Mashros, Nordiana; Warid, Muhammad Naqiuddin Mohd; Lopa, Romana Sarker

doi:10.1088/1757-899x/527/1/012072

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…S.F. Azhari et al (39) evaluated the critical interval at a roundabout using different statistical methods, namely the Ruff method, the Wu method and the simple Logit method. The Ruff method and the Logit analysis produced similar results of 3.45 seconds, while the Wu method resulted in a critical interval of 3.6 seconds.…”

Section: Discussionmentioning

confidence: 99%

Variable’s prediction of gap acceptance roundabout capacity model – Critical gap

Majid,

Ali

2023

Innovaciencia

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Introduction: The research relevance is determined by the assessment of the capacity of roundabouts and their efficiency are extremely important topics in transport engineering research. As road networks are constantly growing in size and complexity, congestion and insufficient flow capacity are becoming serious problems for traffic. The research aims to determine the critical interval at a certain roundabout using several statistical methods and to compare the results obtained by each of them, respectively. Material and Methods: The statistical methods used in the study included the Ruff, Wu, Troutbeck, Ashworth, and standard deviation methods. Results and Discussion: The results of the study show that the difference between the five methods is minimal, although each method has its characteristics. The analysis of the critical interval for the left and right bands showed that different methods may vary in their estimates, but the overall picture remains within acceptable convergence. The difference between the Wu method and the other methods was found to be negligible, except for the Ashworth method, which has a significant difference in the definition of the critical interval. Conclusion: Thus, all five methods can generally be used to calculate the critical interval at roundabouts. However, due to its simplicity and reliability, the Wu method was recommended for use. The practical significance of the study is that the results provide important guidance and information for the design and management of roundabouts. Estimation of the critical spacing is key to determining the optimal traffic flow regime, which affects safety, flow capacity and convenience for drivers.

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Section: Discussionmentioning

confidence: 99%

Variable’s prediction of gap acceptance roundabout capacity model – Critical gap

Majid,

Ali

2023

Innovaciencia

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“…Wu's model introduced some positive aspects, such as a solid theoretical background, robust results, independence from any model assumptions and a simple calculation procedure. Authors in [68] describe an application of Wu's model to obtain the critical gap of a two-lane roundabout. On the intersection, cameras have been mounted to study the traffic behaviour in terms of arrival and departure time of vehicles.…”

Section: Gap Acceptance Modelsmentioning

confidence: 99%

Roundabouts: Traffic Simulations of Connected and Automated Vehicles—A State of the Art

Campi,

Mastinu,

Previati

et al. 2024

IEEE Trans. Intell. Transport. Syst.

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The paper deals with traffic simulation within roundabouts when both "connected and automated vehicles" (CAVs) and human-driven cars are present. The aim is to present the past, current and future research on CAVs running into roundabouts within the Cooperative, Connected and Automated Mobility (CCAM) framework. Both microscopic traffic simulations and virtual reality simulations by dynamic driving simulators will be considered. The paper is divided into five parts. At first, the literature is analysed using the Systematic Literature Review (SLR) methodology based on Scopus database. Secondly, the influence of CAVs on roundabout-specific design features and configuration is analysed. Gap-acceptance models used to define the capacity of the roundabout, one of its most important key performance indicators, are also presented. Third, the most common simulation software are described and analysed in terms of traffic demand implementation. Then the communication approaches and path management algorithms are studied. An example is proposed on the integration of microscopic traffic simulations and dynamic driving simulators virtual reality simulations. Finally, car following models suitable for roundabout traffic are discussed. There is still a gap between simulations and actual experience. There are reasonable doubts on how modelling and optimizing CAVs' behaviour into roundabouts in view of CCAM. It seems that Cooperative, Connected and Automated Vehicles (CCAVs), more than simply Connected and Automated Vehicles (CAVs), could optimise traffic flow, safety and driving comfort within the roundabout. A very promising technology for traffic simulation within the roundabout seems the one based on dynamic driving simulators.

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“…They used two camcorders to capture the entry and circulatory traffic queue using the stop line as a reference and measuring the conflicting gap (headway) and lag information. This paper used 13 s as the upper threshold for accepted headways and used Raff’s Method, Wu’s Method, and a simple logit method ( 8 ). In his paper titled “Estimating Critical Gap of Roundabouts by Different Methods,” Rui-jun Guo used Raff’s method, Ashworth’s method, and the maximum likelihood method to calculate the critical headway.…”

Section: Literature Reviewmentioning

confidence: 99%

Headway Data Extraction and Highway Capacity Manual Capacity Function Calibration for Roundabouts With Roadside Lidar Data

Whitley

Tian

2022

Transportation Research Record: Journal of the Transportation R

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There have been many research efforts analyzing roundabouts to extract the gap acceptance parameters of critical and follow-up headways at the entry lanes, but most have not had automatic methods of outputting the desired headways. This paper proposes an automatic method for extracting headway information at roundabouts with roadside lidar data and demonstrating the use of the headway output for Highway Capacity Manual (HCM) roundabout capacity function calibration. The advantages of using roadside lidar sensors over video cameras are that it is less computationally demanding, has a greater detection range, and is effective in all lighting conditions. Roadside lidar provides high accuracy cloud points of all road users that can be converted into geolocated trajectories using software developed by the University of Nevada, Reno (UNR). Headway is then extracted using an ArcGIS plugin of Python Scripts developed by the authors. Roadside lidar data were collected at one roundabout in Reno, Nevada, United States during the daytime hours, and headway data were extracted from the trajectory output. With rejected, accepted, and follow-up headways extracted, Raff’s Method was employed to extract the critical headway and the average of the follow-up headways was calculated. These values were used to determine the entry capacity at a roundabout. The results for the capacity were validated with industry standard equations, providing evidence for an automatic method to extract crucial operational information. The methodology proposed in this paper opens the door for several more extended studies with roundabouts, vehicle-pedestrian interactions, and on-ramp merging events.

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Estimation of critical gap at small roundabout

Cited by 3 publications

References 13 publications

Variable’s prediction of gap acceptance roundabout capacity model – Critical gap

Variable’s prediction of gap acceptance roundabout capacity model – Critical gap

Roundabouts: Traffic Simulations of Connected and Automated Vehicles—A State of the Art

Headway Data Extraction and Highway Capacity Manual Capacity Function Calibration for Roundabouts With Roadside Lidar Data

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