Two Vehicular Headways Time Dichotomic Models

Mauro, Raffaele; Branco, Federico

doi:10.5539/mas.v6n12p1

Cited by 12 publications

(7 citation statements)

References 4 publications

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“…When, in turn, the mean of the counts exceeds the variance the choice of the probability distribution can fall on the binomial distribution; however, it should be particularized with the measured data [see, e.g., Devroye (1986)]. Such distributions are discussed in more specialized sources [such as, for instance, May (1990), Lord and Mannering (2010), and Mauro and Branco (2012)]. The criterion for choosing alternative traffic counting models has been exposed by Mauro and Branco (2013); the same source shows the theoretical probability distributions of arrivals (namely, the binomial, Poisson, and negative binomial distribution) and their expressions as a function of the sample statistics.…”

Section: Counting Distributionsmentioning

confidence: 99%

Methodological Frontier in Operational Analysis for Roundabouts: A Review

Giuffrè

Granà

Tumminello

2016

Front. Built Environ.

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Several studies and researches have shown that modern roundabouts are safe and effective as engineering countermeasures for traffic calming, and they are now widely used worldwide. The increasing use of roundabouts and, more recently, turbo and flower roundabouts, has induced a great variety of experiences in the field of intersection design, traffic safety, and capacity modeling. As for unsignalized intersections, which represent the starting point to extend knowledge about the operational analysis to roundabouts, the general situation in capacity estimation is still characterized by the discussion between gap acceptance models and empirical regression models. However, capacity modeling must contain both the analytical construction and then solution of the model, and the implementation of driver behavior. Thus, issues on a realistic modeling of driver behavior by the parameters that are included into the models are always of interest for practitioners and analysts in transportation and road infrastructure engineering. Based on these considerations, this paper presents a literature review about the key methodological issues in the operational analysis of modern roundabouts. Focus is made on the aspects associated with the gap acceptance behavior, the derivation of the analytical-based models, and the calculation of parameters included into the capacity equations, as well as steady-state and non-steady-state conditions and uncertainty in entry capacity estimation. At last, insights on future developments of the research in this field of investigation will be also outlined.

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Section: Counting Distributionsmentioning

confidence: 99%

Methodological Frontier in Operational Analysis for Roundabouts: A Review

Giuffrè

Granà

Tumminello

2016

Front. Built Environ.

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“…To this end, a sensitivity analysis was performed, carried out by varying input parameter values of the model within the respective variability ranges as usually observed in reality; the results obtained from the algorithm varied in a reasonable range. Moreover, a comparison was made between time headways observed in some measurement campaigns on operational roads [14][15][16] and those obtained from the model, in which simulation input data were the flows observed in measurement campaigns as well as other empirical data.…”

Section: Random Test Generation Algorithmmentioning

confidence: 99%

Contribution to the platoon distribution analysis in steady-state traffic conditions

Mauro

Branco

Guerrieri

2014

Period. Polytech. Civil Eng.

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The traffic flow analysis and the relevant vehicle distribution ("free-moving" or "platooned" vehicles) IntroductionThe traffic flow composition and the relevant presence of vehicle platoons is particularly interesting in traffic study, and more generally in Highway Engineering, with reference to a plethora of theoretical and practical applications. For instance, as for "traffic operations" [1][2][3][4], it is well known how the presence of platoons can influence breakdown probability [5,6]. Moreover, platoon analyses turned out to be important also in the study of car accidents and road safety [7]. Such a very high practical interest accounts for the numerous models developed over the years. By way of an example, it is worth mentioning the research conducted by Baras et al. [8], which also considers facilities with interrupted flow -and the most recent studies by Ramezani et al. [9] and Jiang et al. [10]. Still today, therefore, the topic has a remarkable scientific and practical interest and deserves in-depth analysis.At first, this article briefly describes the Pearson type III distribution which represents a time headway probability model (more specifically, a generalized mathematical model). The peculiarity of the Pearson type III distribution is its capacity to generate distribution families depending on the chosen model parameters, which can be suited to a plethora of types of traffic phenomena. In the course of this research, some of the above formulations were used to analyse a vehicle distribution within a traffic flow in steady-state conditions and notably to identify the presence and composition of vehicle platoons. In order to apply this analysis to a great number of observations, a specific algorithm was designed and calibrated according to empirical surveys, suitable to randomly simulate a traffic flow and to "identify" the essential characteristics of any present vehicle platoon. The algorithm was implemented to generate realizations of the random function Q(t) (i.e. a traffic flow on a road cross-section in function of time t) starting from input data. The resulting random functions were properly studied and their main characteristics (i.e. non-random functions: mathematical hope and variance) were determined to confirm the steady state flow hypothesis assumed for the development of this study.

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“…This paper will show that, as a matter of fact, by considering the results developed as closed-form expressions through the queuing theory, it is possible to estimate if and which effects the slip lane geometry and control type (e.g. slip lane composition and length) can (Mauro & Branco, 2012), according to P-K relationships (Pollaczek, 1930;Khinchine, 1932;Kleinlock, 1975), b = E[s] can be calculated as following: By means of (1) C E,R follows as:…”

Section: Introductionmentioning

confidence: 99%

Right-turn Bypass Lanes at Roundabouts: Geometric Schemes and Functional Analysis

Mauro¹,

Guerrieri²

2012

MAS

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Right-turn bypass lanes can be implemented in conventional and innovative roundabout intersections to increase the capacity and improve the global functional performances. The Right-turn bypass lanes (also called slip lanes) can be distinguished according to the planimetric layout and the entry control type (stop, yield slip or Free Flow acceleration lane). This paper presents a closed-form model for the estimation of capacity, delays and level of service of roundabout equipped with Right-turn bypass lanes, considering the effect of geometric slip lane schemes, control type, vehicular and pedestrian flow. In order to examine the traffic conditions which can benefit from slip lane roundabouts in terms of capacity and delays, compared to traditional schemes which have no additional lanes, a great number of analyses have been carried out by considering different O/D matrices and vehicle and pedestrian flow vectors. Such comparisons have been made by considering the control delays in function of different O/D matrices. Such O/D matrices describe the most significant situations of traffic demand which can be of interest for the road intersections under study.

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Two Vehicular Headways Time Dichotomic Models

Cited by 12 publications

References 4 publications

Methodological Frontier in Operational Analysis for Roundabouts: A Review

Methodological Frontier in Operational Analysis for Roundabouts: A Review

Contribution to the platoon distribution analysis in steady-state traffic conditions

Right-turn Bypass Lanes at Roundabouts: Geometric Schemes and Functional Analysis

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