Let's Connect
Follow Us
Watch Us
(+385) 1 2380 262
journal.prometfpz.unizg.hr
Promet - Traffic&Transportation journal

Accelerating Discoveries in Traffic Science

Accelerating Discoveries in Traffic Science

Articles

Vol. 24 No. 5 (2012)
Published on 25.09.2012

Shuguang Li
2012 (Vol 24), Issue 5
Single vehicle type dynamic marginal cost model is extended to multiple vehicle type dynamic one based on time-dependent multiple vehicle type queue analysis at a bottleneck. A dynamic link model is presented to model interactions between cars and trucks, given the link consists of two distinct segments. The first segment is the running segment on which cars (trucks) run at their free-flow speeds and the second segment is the exit queue segment. A car or a truck is assumed to be a point without length. The class-specific pi parameter is used to transform the effect of truck into passenger car equivalents, so the exit flow of cars and trucks can be calculated according to the exit capacity of a bottleneck. The analytic expression of multiple vehicle type dynamic marginal cost function is deduced under congested and uncongested conditions. Then a heuristic algorithm is presented in solving multiple vehicle type dynamic queues, tolls under system optimum and user equilibrium conditions. The numerical example illustrates the simplicity and applicability of the proposed approach.

Robert Mittermayr, Johann Blieberger, Andreas Schöbel
2012 (Vol 24), Issue 5
Deadlock analysis for railway systems differs in several aspects from deadlock analysis in computer science. While the problem of deadlock analysis for standard computer systems is well-understood, multi-threaded embedded computer systems pose new challenges. A novel approach in this area can easily be applied to deadlock analysis in the domain of railway systems. The approach is based on Kronecker algebra. A lazy implementation of the matrix operations even allows analysing exponentially sized systems in a very efficient manner. The running time of the algorithm does not depend on the problem size but on the size of the solution. While other approaches suffer from the fact that additional constraints make the problem and its solution harder, our approach delivers its results faster if constraints are added. In addition, our approach is complete and sound for railway systems, i.e., it generates neither false positives nor false negatives.

Kire Dimanoski, Gordan Stojić, Slavko Vesković, Ilija Tanackov
2012 (Vol 24), Issue 5
The participation of the national rail networks in the European corridors requires certain modifications and their redefinition. Because the railway stations are special parts of the railway networks, they should be modernized, especially in south-eastern Europe. The main issue in the process of construction or reconstruction of railway stations is dimensioning (projection) of infrastructure facilities. The dimensioning of the infrastructure capacity is in direct correlation with the projected technology of work and the planned volume of traffic. This paper presents the simulation model which allows sizing facilities of border rail stations on the basis of the defined work and traffic technology.

Jun-Hyuk Kim, Soonhu Soh
2012 (Vol 24), Issue 5
This paper provides a case study of hub-and-spoke school bus transportation network design. The case study here utilizes a mathematical model that is the P-median optimization model to determine optimal hub locations. The P-median problem is a combinatorial optimization problem that includes many binary variables and constraints. The selected objective of the model is to minimize the total travel time satisfying other operational constraints. To elevate usability of decision making in the future, we implement the simulation model through the template model in spreadsheet platform. The developed model is used as a future reference to find operational directions of school bus managing policy and also tested on the case of Wonkwang University.

Jun-Qiang Leng, Yu-Qin Feng, Ya-Ping Zhang, Yi He
2012 (Vol 24), Issue 5
This paper discusses the travel time reliability of road network under ice and snowfall conditions. With the introduction of correction function for the influence of ice and snowfall conditions on free travel time and capacity, the function of travel time was established. According to the limitation of the current travel time reliability, the new definition was defined on the basis of quantifying the relationship between LOS (Level of Service) and travel time reliability. The breakthrough of the traditional idea that the route travel time reliability model was set by general series system was made by considering the route as a whole unit; instead of using a paralleling system; another breakthrough was made to calculate the weighted average travel time reliability of OD (Original Destination) pair. On the basis of OD pair travel time reliability, the road network reliability model was set up. A partial road network was taken as an example to validate the effectiveness and practicality of the evaluation methodology.

Leposava Puzavac, Zdenka Popović, Luka Lazarević
2012 (Vol 24), Issue 5
The analysis of track behaviour under vertical load is traditionally based on the presumption that the stresses and deformations in track elements can be determined by the application of the Winkler’s Hypothesis. The rail is considered a beam on a continuous elastic foundation. The basis of the hypothesis is a presumption about the proportionality between the load and deflection. However, it is empirically known that the track and track foundation elements in a real environment during the railway exploitation behave neither linearly, nor completely elastically. Moreover, there is a problem with unevenness of the track stiffness along the track. This paper analyses the track stiffness from the aspect of its influence on the quality of the vertical track geometry. The paper analyses optimum stiffness. Optimum stiffness is conditioned by the single stiffness of all the elements of the superstructure and substructure as well as by their mutual compatibility.

Jelena Simićević, Nada Milosavljević, Goran Maletić
2012 (Vol 24), Issue 5
Parking charge is a powerful tool for solving parking and traffic congestion problems. In order to achieve the expected effects without any adverse impact it is necessary to understand well the users’ responses to this policy. This paper, based on a sample of interviewed parking garage users, has developed binary logit model for identification and quantification of characteristics of users and trips, on which the acceptance of parking price is dependent. In addition, multinomial logit model has been made in order to predict what the users will opt for when faced with an increase in parking price. For the first time the parameter “shorten duration” has been introduced which has shown to be the most significant in making behaviour-related decisions. The results show that the users with the purpose work are the most sensitive to an increase in parking charge, what can be deemed positive for policy makers. However, great sensitivity of the users with the purpose shopping should cause their concern. The results of the multinomial model show that they would not discontinue coming into the area after all.

Martin Jacura, Lukáš Týfa
2012 (Vol 24), Issue 5
The key issue in improving the appeal of public mass transport is the optimal arrangement of transfer nodes. The objective is to propose a comfortable, simple and safe environment for both passengers and operators, and a solution which is economical to construct and operate. Although each transfer node is unique and specific, it is beneficial to have a general idea on the layout of a project to construct or reconstruct such a transfer node. This project should, in particular, stem from the traffic intensity of single transport modes, the volume of single transfer links, and the nature and significance of traffic routes. This article presents the methodology for determining the appropriate disposition of mass public transport nodes using modified decision tables (one of the tools of systems analysis) with specific data particularly applicable in the Czech Republic.

Jasmina Pašagić Škrinjar, Kristijan Rogić, Ratko Stanković
2012 (Vol 24), Issue 5
In this paper the problems of locating urban logistic terminals are studied as hub location problems that due to a large number of potential nodes in big cities belong to hard non-polynomial problems, the so-called NP-problems. The hub location problems have found wide application in physical planning of transport and telecommunication systems, especially systems of fast delivery, networks of logistic and distribution centres and cargo traffic terminals of the big cities, etc. The paper defines single and multiple allocations and studies the numerical examples. The capacitated single allocation hub location problems have been studied, with the provision of a mathematical model of selecting the location for the hubs on the network. The paper also presents the differences in the possibilities of implementing the exact and heuristic methods to solve the actual location problems of big dimensions i.e. hub problems of the big cities.

Raffaele Mauro, Marco Cattani
2012 (Vol 24), Issue 5
The road intersection design requires a choice among different layouts, for example signalized intersections or roundabouts. Generally, layouts which provide higher level of services are the most expensive ones. For this reason, the choice has to consider both fixed and variable costs, the latter consisting in the delays suffered by the drivers crossing the junction. The paper presents a procedure to compare different layouts, taking into account the costs of construction, management/maintenance and delays. The cost of delay is estimated with different traffic conditions, by the evaluation of the layout performance, in terms of delays at the approaches. With the example traffic conditions and parameters values considered in the paper, the compact roundabout turns out to be the layout with the least overall cost. The examples of sensitivity analyses are also provided to understand the cost dependence on the parameters used.

Borna Abramović
2012 (Vol 24), Issue 5

Tino Bucak
2012 (Vol 24), Issue 5


Accelerating Discoveries in Traffic Science |
2024 © Promet - Traffic&Transportation journal