A universal procedure for capacity determination at unsignalized (priority-controlled) intersections

Wu, Ning

doi:10.1016/s0191-2615(00)00012-6

Cited by 70 publications

(43 citation statements)

References 6 publications

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“…This method has been incorporated into a software packages widely known as RODEL (Crown [13] [20]). The detailed formula for entry flow is discussed by Wu [21,22]. The French Model is based on the work carried out by Louah [23] which was later incorporated into a model known as GIRABASE [24].…”

Section: International Roundabout Capacity Modelsmentioning

confidence: 99%

Analysis of roundabout capacity under high demand flows

Al-Madani

Saad²

2009

WIT Transactions on the Built Environment

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Estimation of the entry capacity of roundabouts greatly varies between one method and another in their input requirements, model complexity and estimate accuracy. Several available models for the capacity estimation at approach entries of the roundabouts are tested here and compared for high traffic demand condition. The estimated entry capacities along with the actual entry demand are then compared for various gathered circulating flows. Two models for capacity estimate are developed for triple circulating lanes by triple and dual entry lanes. Thirteen roundabouts in Bahrain are used for the models' development and for the comparison purposes between the various tested methods. The geometric data were gathered from the actual drawings, scaled aerial photographs and from the field. The necessary traffic data were gathered during peak periods. Substantial differences in estimating capacities were observed between the various available international methods. This makes the judgment of accepting or rejecting the estimated capacity difficult. The developed model fall well in between the tested international models and matched the actual data reasonably well. The methods with complicated input parameters and extensive equations, as aaSIDRA, UK RODEL, French and Indian methods, did not prove to be better than much simpler ones like Swiss or FHWA methods. The findings are quite essential for traffic planners in making judicious decisions regarding roundabouts' performance. There is a real need for a more consistent model for the capacity estimation of roundabouts.

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Section: International Roundabout Capacity Modelsmentioning

confidence: 99%

Analysis of roundabout capacity under high demand flows

Al-Madani

Saad²

2009

WIT Transactions on the Built Environment

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“…The vehicle refers to the cars, when there are other vehicles mixed with, equivalent capacity of the standard vehicle (car) is used to be a unit (Zhang, Fang, Li, & Lu, 2015). Wu improved the calculation method of traffic capacity; at the unsignalized intersection (Wu, 2001). Maji used the user equilibrium model to optimize the road network flow and evaluate the intersection under the premise of the intersection (Maji & Jha, 2010).…”

Section: Relevant Scholarshipmentioning

confidence: 99%

Research on Influence of Community Opening on Road Capacity

Li¹,

Zhong²,

Zhang³

et al. 2017

JMS

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Under the background of promoting the block system, the paper mainly focuses on the impact on the surrounding road capacity caused by the openness of the communities. Firstly, the basic capacity model of the road is established by using Newton's second law. Then, based on the openness of the district, we analyze the probabilities of the drivers choosing the intersection and exit of the district and the delay rate of the crossing. So we establish the modified road capacity model. Finally, according to the actual situation, the road structure in the surrounding areas and intersection type is divided, and the influence coefficient of the road is introduced, which are used to establish the vehicle traffic mathematical model to quantitatively analyze whether the district opening can promote the road capacity, thus providing a certain theoretical basis for the open policy.

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“…The German model is derived from the Tanner and Wu capacity equation and has been introduced officially into the German Highway Capacity Manual in 2001 [26,27]. The detailed formula for entry flow is discussed by Wu [28,29]. The French model is based on the work carried out by Louah [30] which later was incorporated into a model known as GIRABASE [31].…”

Section: Introductionmentioning

confidence: 99%

“…At least two models are currently available in the recent US literature; the Highway Capacity Manual (HCM 2010) [4] and the Federal Highway Administration (FHWA) models [19,32]. According to Robinson and Rodegerdts [18] the FHWA model is based on Wu's model [28,29].…”

Section: Introductionmentioning

confidence: 99%

Calibration of international capacity models for dual lane roundabouts during saturation flow condition

Al-Madani¹

2012

WIT Transactions on the Built Environment

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Varying differences in the prediction of roundabout capacities were observed between various international models and field data. This study attempts to calibrate 7 international models for forced flow conditions. These include UK, aaSIDRA, Swiss, US FHWA, HCM, French and German models. These are compared with field data collected from 12 large roundabouts in Bahrain. They are compared considering scattered plots, Root Mean Square Error (RMSE) and t-tests. Each model is calibrated by a trial multiplicative factor which is then adjusted in an iterative manner until best match with actual data is achieved. The calibration adjusts the Y-intercept and the slope of each model. The calibration factors, based on the initial results, showed high variations in the adjustment factors between one model and another. The calibrated models showed substantial improvements and were fairly comparable with actual data. The UK, aaSIDRA and French models, with over 40% reduction, required the greatest adjustments to suite the field data. The FHWA model required 35% reduction and the German model required 15% increase to reasonably fit the field data. The HCM method required no adjustments and the Swiss model required a reduction of 5%. The calibration factors were as follows in respective order: 0.5225, 0.515, 0.585, 0.65, 1.16, 1.0 and 0.95. While differences in capacity prediction between one international model and another confuse the practitioners; calibrated models assist them to have just predictions regarding roundabout capacities during forced flow conditions. The developed calibrations require further investigation to reduce the deviation between the calibrated models and the actual data.

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A universal procedure for capacity determination at unsignalized (priority-controlled) intersections

Cited by 70 publications

References 6 publications

Analysis of roundabout capacity under high demand flows

Analysis of roundabout capacity under high demand flows

Research on Influence of Community Opening on Road Capacity

Calibration of international capacity models for dual lane roundabouts during saturation flow condition

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