An International Review of Roundabout Capacity Modelling

Yap, Yok Hoe; Gibson, Helen; Waterson, Ben

doi:10.1080/01441647.2013.830160

Cited by 42 publications

(28 citation statements)

References 49 publications

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“…He also developed a multivariate model for the prediction of maximum entry flow by considering the circulating flow, exit flow and roundabout geometric characteristics. Yap et al [12] examined the three main methodologies based on the following models: fully empirical, gap acceptance and simulation software. They found that each of these methodologies on their own could not completely explain the complex behavioural and physical processes involved in roundabout entries due to their limitations.…”

Section: Introductionmentioning

confidence: 99%

Traffic Efficiency Evaluation of Elliptical Roundabout Compared with Modern and Turbo Roundabouts Considering Traffic Signal Control

Hatami

Aghayan

2017

PROMET

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Section: Introductionmentioning

confidence: 99%

Traffic Efficiency Evaluation of Elliptical Roundabout Compared with Modern and Turbo Roundabouts Considering Traffic Signal Control

Hatami

Aghayan

2017

PROMET

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“…e theoretical approach relies on gap acceptance. e gap-acceptance method is based on driver characteristics [6][7][8], that is, the estimation of individual headway parameters between entering and circulating traffic flows. e critical gap can be estimated using different methods (Wu, Raff, and others).…”

Section: Literature Reviewmentioning

confidence: 99%

Extent of Entry Capacity Loss at Roundabouts Caused by Rainy Conditions

Ben-Edigbe

Pakshir

Ibijola

2018

Advances in Civil Engineering

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Entry capacity loss at multilane roundabouts caused by rainfall was investigated. Traffic and rainfall data were collected continuously for eight weeks at selected sites in South Africa and Malaysia. ree classes of rainfall (light, moderate, and heavy) were used. Both linear and exponential techniques were used to model the relationship between entry and circulating traffic flows. Correction factor for entry angle and radius was introduced in the linear model equations to allow for variations in geometric data. Correction factor is not required for the exponential model technique. Notwithstanding, both techniques predicted that entry capacity loss would result from rainfalls irrespective of their intensity. Results show that light rainfall may cause about 5% entry and circulating capacity loss, moderate rainfall may cause about 12% capacity loss, and heavy rainfall may cause about 17% capacity loss. is paper proposed further studies into the effect of two circulating lanes rather than one on entry capacity at roundabouts.

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“…Finally, the entry capacity at a single-lane roundabout (one lane at entries and one at the ring carriageway) can be determined with numerous models [32]. This research used the following Equation (13) [28], in which Qc stands for the circulating flow in front of the entry in question:…”

Section: Free-flow Bypass Lanementioning

confidence: 99%

Improving the Sustainability of Transportation: Environmental and Functional Benefits of Right Turn By-Pass Lanes at Roundabouts

Guerrieri¹,

Corriere²,

Rizzo³

et al. 2015

Sustainability

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Abstract:The functional performances of conventional roundabouts (single-lane and multi-lane) and innovative roundabouts (spiral, flower, C and turbo) can be improved through right-turn bypass lanes controlled by stop, yield or free-flow signs. The article presents evaluations of the emissions of air pollutants (carbon dioxide, nitrogen oxides, particle pollution (PM10 and PM2.5)), fuel consumption and construction, management, energetic and environmental costs in roundabouts without or with bypass lanes (controlled by stop, yield or free-flow). The suggested methodology has a general character and can be applied as a multi-parametric criterion for choosing road intersections, although, in the present paper, it has been employed only for a case study. For the aims of this research, we employed recent closed-form formulations to determine roundabout performances; moreover, we used the COPERT IV ® software to estimate air emissions in nine different types of vehicles. Numerous traffic simulations were carried out. The variation in the maximum hourly traffic Qmax and annual traffic QTOT provided the appropriate domains of the examined geometric layouts, both in functional and environmental terms and with regard to generalized costs, estimated for a 10-year period. It resulted that the introduction of right-turn bypasses in all arms of conventional roundabouts with a one ring lane and one lane at the entries (single-lane roundabouts) is the most cost-effective when the flows entering the roundabout are higher than Qmax = 2000 veh/h. Moreover, free-flow bypass lanes always OPEN ACCESSSustainability 2015, 7 5839 provide greater capacity and lower delays than stop-or yield-signaled bypasses. However, with extremely high Qmax values, stop-controlled bypasses guarantee lower fuel consumption, while those with a yield sign lower total costs.

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An International Review of Roundabout Capacity Modelling

Cited by 42 publications

References 49 publications

Traffic Efficiency Evaluation of Elliptical Roundabout Compared with Modern and Turbo Roundabouts Considering Traffic Signal Control

Traffic Efficiency Evaluation of Elliptical Roundabout Compared with Modern and Turbo Roundabouts Considering Traffic Signal Control

Extent of Entry Capacity Loss at Roundabouts Caused by Rainy Conditions

Improving the Sustainability of Transportation: Environmental and Functional Benefits of Right Turn By-Pass Lanes at Roundabouts

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