State of the art and computational aspects of time-dependent waiting models for non-signalised intersections

Mauro, Raffaele; Pompigna, Andrea

doi:10.1016/j.jtte.2019.09.007

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…Circular Organization For human-driven vehicles (HVs), the respective applicable scenarios and conditions for roundabouts and intersections have been clearly defined [7][8][9], and the state of the art calculation method of capacity can be found in [10,11]. However, when it comes to the era of CAVs, the situation may be different, and there is a lack of direct comparison of the performance of intersections and roundabouts in existing literature.…”

Section: Intersectional Organizationmentioning

confidence: 99%

Junction Management for Connected and Automated Vehicles: Intersection or Roundabout?

Zhu

2021

Sustainability

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The concept of signal-free management at road junctions is tailored for Connected and Automated Vehicles (CAVs), in which the conventional signal control is replaced by various right-of-way assignment policies. First-Come-First-Served (FCFS) is the most commonly used policy. In most proposed strategies, although the traffic signals are replaced, the organization of vehicle trajectory remains the same as that of traffic lights. As a naturally signal-free strategy, roundabout has not received enough attention. A key motivation of this study is to theoretically compare the performance of signalized intersection (I-Signal), intersection using FCFS policy (I-FCFS), roundabout using the typical major-minor priority pattern (R-MM), and roundabout adopting FCFS policy (R-FCFS) under pure CAVs environment. Queueing theory is applied to derive the theoretical formulas of the capacity and average delay of each strategy. M/G/1 model is used to model the three signal-free strategies, while M/M/1/setup model is used to capture the red-and-green light switch nature of signal control. The critical safety time gaps are the main variables and are assumed to be generally distributed in the theoretical derivation. Analytically, I-Signal has the largest capacity benefiting from the ability to separate conflict points in groups, but in some cases it will have higher delay. Among the other three signal-free strategies, R-FCFS has the highest capacity and the least average control delay, indicating that the optimization of signal-free management of CAVs based on roundabout setting is worthy of further study.

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Section: Intersectional Organizationmentioning

confidence: 99%

Junction Management for Connected and Automated Vehicles: Intersection or Roundabout?

Zhu

2021

Sustainability

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“…Queue and delay evaluations for unsignalized intersections resort to heuristic models for the time-dependent queue, which allow analyzing the whole range of situations that can occur in the real cases. The coordinate transformation method [3], in fact, makes time-dependent queue formulas available for stationary and non-stationary condition treatment, i.e., for non-congested and congested traffic, respectively [4]. From this point of view, capacity is the key variable as it reflects the queue discharge rate [5].…”

Section: Introductionmentioning

confidence: 99%

“…In this case, for each entry, we can consider the simple priority system in Figure 1b. This is a fondant queueing system in highway engineering, in which a traffic flow q on a secondary stream (i.e., non-priority) wants to turn right to merge the traffic flow Q on the main stream (i.e., priority) [4]. The priority flow Q is clearly a disturbance for q, and therefore it is called "opposing flow" or "conflict flow", or more specifically "circulating flow" for roundabouts.…”

Section: Introductionmentioning

confidence: 99%

New Extensions and Applications of the Modified Chumanov Model for Calculating Entry Capacity of Single-Lane Roundabouts

2020

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Over the past decades many models for roundabout capacity have been proposed. Attention to this research sector has never stopped and still today new formulations are always being studied, especially in view of their direct application in design practice. This paper reports the first noteworthy results of a research concerning the Modified Chumanov (MC) model, which can be used to estimate the capacity of single-lane roundabout entrances. After a detailed examination of the original model recommended by the Russian guidelines for small urban roundabouts, the paper proposes some extensions which allow using the revised model even for larger intersections. The MC model also includes some parameterizations that allow its application with different road pavement surface conditions (i.e., dry and wet conditions). The MC entry capacity model, as function of circulating flow and other parameters dependent on geometry and environmental conditions, was compared with 15 widespread models considering a typical medium-sized single-lane roundabout. A validation test was carried out considering four capacity–circulating flow datasets from the literature. The proposed MC model showed good flexibility in adapting to data. This flexibility appears better than the most recent models by Highway Capacity Manual, in the absence of local calibration of the psychotechnical parameters.

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“…the American Highway Capacity Manual -HCM (TRB, 2016). In addition, these aspects of measuring the operational quality of the intersection by modelling the waiting phenomena and the delays that users spend to perform the manoeuvres require more in-depth mathematical tools than the most common queue theory formulas (Mauro and Pompigna, 2020). For these reasons, the HCM provides approximate solutions which, although with some limitations, allow to face the problem in a conventional way.…”

Section: Introductionmentioning

confidence: 99%

Testing roundabout capacity models: a practical aid for choosing the right one based on total capacity calculation

Mauro¹

2020

European Transport/Trasporti Europei

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The determination of efficiency measures, under a known traffic demand, is a central aspect of roundabouts analysis. Many capacity formulations have been available for some time in different countries relating to different roundabout layouts. This paper refers to fifteen roundabout entry capacity models used above all in the European countries, highlighting their input requirements and their algorithm complexity. The formulations reviewed are then compared referring to a test roundabout, with a simple and widespread layout. Monte Carlo simulation have been performed considering 5,000 traffic distribution matrices for each capacity model. The results obtained are critically assessed resorting to the calculation of roundabout total capacity. The probability distributions of total capacity allow finding a model that stands out among all as an advisable choice for a suitable capacity formulation, acting as a synthesis of all those examined. This can be of considerable use in view of practical applications, for the design of efficient and safe roundabout intersections in situations in which a country-specific capacity formulation is not available.

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State of the art and computational aspects of time-dependent waiting models for non-signalised intersections

Cited by 11 publications

References 11 publications

Junction Management for Connected and Automated Vehicles: Intersection or Roundabout?

Junction Management for Connected and Automated Vehicles: Intersection or Roundabout?

New Extensions and Applications of the Modified Chumanov Model for Calculating Entry Capacity of Single-Lane Roundabouts

Testing roundabout capacity models: a practical aid for choosing the right one based on total capacity calculation

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