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Promet - Traffic&Transportation journal

Accelerating Discoveries in Traffic Science

Accelerating Discoveries in Traffic Science

Articles

Vol. 28 No. 3 (2016)
Published on 27.06.2016

Momčilo Dobrodolac, Predrag Ralević, Libor Švadlenka, Valentina Radojičić
2016 (Vol 28), Issue 3

The European postal directives and Serbian legislation as well define the quality standards for universal service obligations at the aggregate level, i.e. for all postal items transferred by the postal operator. This paper proposes a new concept where the transit time is defined by the customer and specified for each shipment. The paper considers three different models of this new concept. However, the one where a customer could choose between two alternatives: D+1 and D+3 transfer, is analysed in details. By using the attitudes of examined customers, forecasting methods and analysis of revenues from the past, it is assessed at what price the new postal service should be offered to achieve the highest revenue. The proposed methodology was tested and verified in the case of the Post of Serbia. The results indicate that the best would be to offer the service D+1 at the 40% increased price compared to the existing prices.


Licai Yang, Yunfeng Shi, Shenxue Hao, Lei Wu
2016 (Vol 28), Issue 3

The traffic behaviours of commuters may cause traffic congestion during peak hours. Advanced Traffic Information System can provide dynamic information to travellers. Due to the lack of timeliness and comprehensiveness, the provided information cannot satisfy the travellers’ needs. Since the assumptions of traditional route choice model based on Expected Utility Theory conflict with the actual situation, a route choice model based on Game Theory is proposed to provide reliable route choice to commuters in actual situation in this paper. The proposed model treats the alternative routes as game players and utilizes the precision of predicted information and familiarity of traffic condition to build a game. The optimal route can be generated considering Nash Equilibrium by solving the route choice game. Simulations and experimental analysis show that the proposed model can describe the commuters’ routine route choice decision
exactly and the provided route is reliable.


Mina Ghanbarikarekani, Soheil Sohrabi, Ali Vefghi
2016 (Vol 28), Issue 3
Optimization of signal timing in urban network is usually done by minimizing the delay times or queue lengths. Sincethe effect of each intersection on the whole network is not considered in the mentioned methods, traffic congestion may occur in network links. Therefore, this paper has aimed to provide a timing optimization algorithm for traffic signals using internal timing policy based on balancing queue time ratio of vehicles in network links. In the proposed algorithm, the difference between the real queue time ratio and the optimum one for each link of intersection was minimized. To evaluate the efficiency of the proposed algorithm on traffic performance, the proposed algorithm was applied in a hypothetical network. By comparing the simulating software outputs, before and after implementing the algorithm, it was concluded that the queue time ratio algorithm has improved the traffic parameters by increasing the flow as well as reducing the delay time and density of the network.

Xinjun Lai, Jun Li, Zhi Li
2016 (Vol 28), Issue 3
A subpath-based methodology is proposed to capture the travellers’ route choice behaviours and their perceptual correlation of routes, because the original link-based style may not be suitable in application: (1) travellers do not process road network information and construct the chosen route by a link-by-link style; (2) observations from questionnaires and GPS data, however, are not always link-specific. Subpaths are defined as important portions of the route, such as major roads and landmarks. The cross-nested Logit (CNL) structure is used for its tractable closed-form and its capability to explicitly capture the routes correlation. Nests represent subpaths other than links so that the number of nests is significantly reduced. Moreover, the proposed method simplifies the original link-based CNL model; therefore, it alleviates the estimation and computation difficulties. The estimation and forecast validation with real data are presented, and the results suggest that the new method is practical.

Goran Vojković, Neven Grubišić, Lea Vojković
2016 (Vol 28), Issue 3

Existing classification of the Croatian seaports does not fit the level and meet the needs of the economic development of the Republic of Croatia, particularly after the Republic of Croatia joined the European Union. Equalizing public service offered by a port with the purpose of the port itself (general purpose – port open for public traffic, special purpose – port not open for public traffic) limits the economic development and aggravates the implementation of the basic market policies of the EU. Therefore, modernisation of the basic classification of ports in the Croatian legislation is suggested. Basic categorization of ports should be as follows: public service ports, private service ports and private ports for private needs of an entrepreneur.


Selahattin Karabay, Erkan Köse, Mehmet Kabak, Eren Ozceylan
2016 (Vol 28), Issue 3
This paper studies a real-life public sector facility location problem. The problem fundamentally originated from the idea of downsizing the number of service centres. However, opening of new facilities is also considered in case the current facilities fail to fulfil general management demands. Two operation research methodologies are used to solve the problem and the obtained results are compared. First, a mathematical programming model is introduced to determine where the new facilities will be located, and which districts get service from which facilities, as if there were currently no existing facilities. Second, the Stochastic Multi-criteria Acceptability Analysis-TRI (SMAA-TRI) method is used to select the best suitable places for service centres among the existing facilities. It is noted that the application of mathematical programming model and SMAA-TRI integration approach on facility location problem is the first study in literature. Compression of outcomes shows that mixed integer linear programming (MILP) model tries to open facilities in districts which are favoured by SMAA-TRI solution.

Mehrzad Ebrahemzadih, Omid Giahi, Farshad Foroginasab
2016 (Vol 28), Issue 3
This study tried to find the original causes of road accidents to prevent their occurrence. This was a descriptive-analytic retrospective study which assessed 1,000 cases of road accidents leading to death during 2003-2013 using the Tripod Beta method. The latent problems, the contributing preconditions, and corrective strategies for the prevention of occurrence of these accidents were determined. The findings of this study revealed that violation of traffic safety rules, especially deliberate violations and risk-takings decreased with increasing age. In comparative status of the superficial problems, illegal and impermissible speed of drivers accounted for 19.10%, in comparative status of preconditions, violation of safety rules accounted for 32.6% and finally, in comparative status of the latent problems, the presence of financial constraints and time pressure in designing and manufacturing of the cars, and quality of city streets, roads, accounted for 20.1%, of the leading causes of occurrence of accidents in this study.

Sebastjan Škerlič, Robert Muha
2016 (Vol 28), Issue 3

Participating in the automotive industry brings new responsibilities for suppliers who, in order to meet customer demands, must strive towards improving business processes, while at the same time reducing costs. These demands can disrupt the operations of companies that do not have a system for controlling logistics costs. On the other hand, customer demands can be the cause of other types of disruptions in companies that have such a system in place, stemming from an excessive focus on cost reduction. To tackle this problem, a survey was conducted on a sample of 30 Slovenian companies that operate as suppliers in the automotive industry. Its objective was to determine how different customer demands along the supply chain can affect the business processes of suppliers and the level of logistics costs. The survey revealed that companies that use a system for controlling logistics costs experience fewer disruptions in their business processes in their efforts to satisfy customer demands. These companies also display a higher level of integration of business processes and use a different approach when dealing with the various participants of the supply chain. The survey also sets clear participation guidelines for suppliers in the supply chain of the automotive industry and points out how companies can benefit from using a system for controlling logistics costs in other ways, aside from the cost controlling aspect.


Fernando González-Laxe, Isabel Novo-Corti, Diana Mihaela Pociovalisteanu
2016 (Vol 28), Issue 3
The recent creation of transport and information networks opens up two new and outstanding options: the interconnection of the economic areas and a new mediation between offer and demand in shipping. In this document the different ways of organization adopted by shipping companies were reviewed; their agreements, alliances, mergers and acquisitions, so as to determine the different levels of hierarchy among them. Secondly, a new port classification was proposed in accordance with the structure and development of shipping companies, together with the degree of port specialization within the framework of the recent spatial integration.

Daiquan Xiao, Zhihe Wen, Xuecai Xu, Željko Šarić
2016 (Vol 28), Issue 3

Freeway greening and traffic safety has aroused more and more attention. The purpose of this study is to investigate the role of flexible green planting in buffering out-of-control vehicles. The stopping distances of vehicle rushing into greening were tested at 8 group of initial speeds range from 5km/h to 40km/h in green belt, and a simplified mathematical model was built up to simulate the buffering process. The results indicated that the greening plants have certain buffering effect on vehicles and alleviate the crash damage within 30m of stopping distance for the vehicles under 40km/h, while the simplified mathematical model could reflect the buffering process of the plants actually by simulating the speed attenuation process, and it was found that the two types of resistance produced by the plants, i.e. counterforce of plants trunks and friction of branches and leaves, are the major factors during the vehicle deceleration.


Jin Xin Cao, Xiao Han Liu
2016 (Vol 28), Issue 3

Increasing traffic demand has already reached the capacity of existing traffic facilities in most cities. In order to alleviate the traffic pressure and expand the capacity of the road network, constructing flyovers has become an effective way in most cities in China. During the period of the flyover construction, work zones occupy road space, impact traffic flow characteristics and driver behaviour; therefore, this causes a significant reduction of the capacity. Researching of the traffic flow characteristics during the period of flyover construction can improve traffic organization and traffic safety around work zones. This study analyses the traffic flow characteristics around the flyover work zone based on the site data collected in Hohhot City, China. This study shows that the traditional Logistic model for the equilibrium speed-density relationship is not applied to the traffic flow around the flyover work zone. Based on an in-depth analysis of the traffic flow characteristics and specific driver behaviours, this paper proposes an improved Logistic model to depict the equilibrium speed-density relationship around the flyover work zone. To analyse the mathematical characteristics of the speed-density relationship, this paper proposes a method to insert virtual data points into the initial data, which can make the fit curve be continuous.



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