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Sanja Marušić
2009 (Vol 21), Issue 6
The paper studies the boundary conditions for the standard LWR model describing the traffic flow. The notion of the BLN (Bardos, Leroux and Nédélec) condition is described. In the context of traffic flow the BLN conditions have some natural interpretation. The conditions on the density and on the flow and their meaning in real-life situations are discussed. KEY WORDS: LWR model, traffic flow, hyperbolic conservation law, boundary conditions

Daniela Koltovska Nečoska, Kristi M. Bombol
2009 (Vol 21), Issue 6
Despite the flow fluctuations and increased traffic demand in the Macedonian cities over the last fifteen years, the Republic of Macedonia is one of those countries which still employ only the traditional systems of traffic management and control. Those are fixed control systems that certainly cause problems such as increased travel times and travel expenses as well as environmental degradation. A general call for “…something has to be done…” becomes obvious. The best practices have shown that this can be realized through unconventional solutions i.e. by means of responsive traffic management. A very reasonable example of such a system is the vehicle actuated control system that we have found to be quite challenging to do our research. Thus, we set up two folded research issues in front of us. The first one was to scientifically prove that vehicle actuated signal control can really be a reasonable substitute for a fixed time signal control, which will enhance the overall signalized intersection performance provided the timing parameters and the detector placement ŕrĺ properly designed. The second one was to indicate that such an advanced control system is feasible and sustainable for Macedonian cities. This paper focuses on the first research issue only. For this purpose, a semi-actuated signal control strategy on an appropriately chosen signalized intersection was designed. The primary objective was to determine the way in which the inductive loop detector placement from the STOP line affects the overall intersection performance. To meet the goal, two scenarios were designed: 1. Detector placement at the STOP line, and 2. Detector placement at 8 metres behind the STOP line. Emphasis was placed on the semi-actuated signal control algorithm design. The designed algorithm was then applied in the net of VISSIM in order to simulate the semi-actuated signal control process. Performance comparison analysis with the formerly pre-timed signal control strategy followed. It was concluded that the overall intersection performance could be improved both by adequate inductive loop detector placement and by interaction with signal parameters. Hence, the placement distances would have to be considered under the limitation conditions only. KEYWORDS: signalized intersection, vehicle actuated control, semi-actuated control, inductive loop detectors, simulation, delays, level of service

Josip Gracin, Antun Stipetić
2009 (Vol 21), Issue 6
The existing postal infrastructure cannot efficiently support the requirements of new technologies and the supply of services on the open market of postal services. Post offices do not meet the new needs, therefore requiring an adjustment to new traffic and service requirements. The functioning of the postal system in the Republic of Croatia was carried out in order to adjust the functional equipment of the system to the introduction of the new technologies and services. At the same time a requirement was set to the public postal operator for more efficient performing of the universal postal service. Based on the analyses of the postal system functioning, a modular procedure of designing the postal network units was proposed and it provides the possibility of adjustment to the new technological, organizational and safety requirements of the postal system. KEY WORDS: postal units, module designing, postal traffic efficiency

Pero Tabak, Tomislav Kljak
2009 (Vol 21), Issue 6
This paper presents the method for developing matrix model of postal traffic flows (ordinary communication items) in public postal network according to volume and different end-to-end (E2E) processes, which can be used for selecting of relevant model for accessing the public postal network. The presented traffic matrix model can be adjusted after the measurement of real volumes and selecting the numbers of different E2E processes (according to geographical input-output request). During the simulation of the model it could be possible to detect the optimal solution for accessing the public postal network. KEY WORDS: traffic modelling, postal services, access to the public postal network

Srećko Krile, Dragan Peraković, Vladimir Remenar
2009 (Vol 21), Issue 6
The paper describes the traffic flow problems in telecommunication networks based on the Internet protocol. The main aim of telecommunication network operator today is to offer an SLA (Service Level Agreement) contract to end users, with provided QoS (Quality of Service) for different classes of services. In order to achieve this, it is necessary to establish the routes between marginal network nodes meeting the network traffic requirements and optimizing the network performances free of simultaneous flows conflicts. In DiffServ/MPLS (Multi-Protocol Label Switching) networks traffic flows traverse the network simultaneously and there may come to collision of concurrent flows. They are distributed among LSPs (Labeled Switching Paths) related to service classes. In LSP creation the IGP (Interior Gateway Protocol) uses simple on-line routing algorithms based on the shortest path methodology. In highly loaded networks this becomes an insufficient technique. In this suggested approach LSP need not necessarily be the shortest path solution. It can be pre-computed much earlier, possibly during the SLA negotiation process. In that sense an effective algorithm for collision control is developed. It may find a longer but lightly loaded path, taking care of the collision possibility. It could be a very good solution for collision avoidance and for better load-balancing purpose where links are running close to capacity. The algorithm can be significantly improved through heuristic approach. Heuristic options are compared in test-examples and their application for collision control is explained. KEYWORDS: Telecommunication networks, collision avoidance, multi-constraint route selection, self-organizing systems, MPLS, QoS

Zvonimir Majić, Irena Jukić, Stanislav Pavlin
2009 (Vol 21), Issue 6
In April 2009, the WHO, (World Health Organization) evaluated the available data on the swine influenza A (H1N1), confirmed the outbreak and declared decision on raising the pandemic phase from five to six. IATA, (International Air Transport Association) invited the airlines to support WHO’s reference laboratories around the world in handling specimens should the outbreak expand further. The specimens shall be transported according to the regulations stipulated for acceptance and transportation of dangerous goods by air. The paper analyses the current infrastructural situation at the airports in Croatia, predispositions related to the trained staff and coordination procedures with the relevant institutions. The implementation of activities complying with the international regulations are suggested in order to conduct measures fighting the pandemic in Croatia. KEY WORDS: pandemic outbreak, regulation, recommendation, specimen, responsibilities, transportation and logistic for biological substances

Robert Muha
2009 (Vol 21), Issue 6
In more advanced countries, the sustainable development concept was accepted both by the politicians and the industrial sector as the underlying philosophy for the preparation of development strategies, practically in all fields. This means using the natural resources within the limits of their renewability, and seeing that the resulting emissions have no negative impact on the environment. The development of Environmental Management Systems (EMS) commenced as a response to global environmental issues and as recognition of awareness that sustainable development is prerequisite for keeping the natural system in proper balance. Road transport of dangerous goods is a very complex activity representing a major potential danger to people and environment. For that very reason, the introduction of certain system tools (standardization of operations), that was a step forward to a safer and more effective operation of the carriers of dangerous goods by road was so welcome. However, this policy requires adequate business environment to be prepared, which is based on transparency and smooth operations as an important marketing advantage that has a bearing on every company’s economic performance. KEY WORDS: sustainable development, road transport of dangerous goods, Environmental Management System (EMS), Responsible Care (RC), ISO 140001, Safety and Quality Assessment System (SQAS).

Nikolina Brnjac, Ivana Ćavar
2009 (Vol 21), Issue 6
Positioning of intermodal terminals is of key importance since it affects the very investment into the terminal, ecological, physical issues and the costs of the operation of individual terminals. Detailed analysis has to be performed by decision-making regarding the siting of intermodal terminals. The work analyzes the relevant criteria necessary for the siting of intermodal terminals. The problem of the proposed research is the structure of intermodal systems in the Republic of Croatia with the case study of inland waterways. The research and the study of the characteristics of intermodal terminals network on inland waterways should result in a concept of system reorganization, i.e. terminal planning methodology. By analysing relevant indicators according to the existing facts, and by using scientific methods and methodologies, the relevant criteria necessary to define the position and categories of intermodal terminals on inland waterways in the Republic of Croatia have been defined and evaluated on the examples of Sisak, Osijek, Vukovar and Slavonski Brod. KEY WORDS: intermodal terminal, intermodal transport, location criteria, inland waterways

Seyyed Mohammad Sadat Hoseini, Mahmmood Fathi, Manouchehr Vaziri
2009 (Vol 21), Issue 5
Controlling the safe distances between vehicles on freeways can be used to prevent many accidents. In this research, image-processing techniques have been used to develop an online system that calculates the longitudinal distances between vehicles. This system facilitates controlling safe distances between vehicles without the need for high technology devices. Our approach is real-time and simple, but efficient operations have been used to reduce the image occlusion problem. The main concept of this system is using simple, quick, and effective algorithms for calculating the position of each vehicle in each image. In this way, traffic parameters like speed and distances between vehicles can be calculated for each vehicle in real time. In addition, aggregate parameters like average speed, density, and traffic flow can be calculated using gathered data of single vehicles. As an application of the developed system, controlling the safe distance between vehicles has been introduced. In this system, in case of a driver who does not observe the safe distance, the scene of violation is stored and can be used by the police agencies. KEY WORDS: image processing, traffic, longitudinal safe distance, real time, occlusion

Tone Magister
2009 (Vol 21), Issue 5
The subject of the paper is the improvement of the aircraft future trajectory prediction accuracy for long-range airborne separation assurance. The strategic planning of safe aircraft flights and effective conflict avoidance tactics demand timely and accurate conflict detection based upon future four–dimensional airborne traffic situation prediction which is as accurate as each aircraft flight trajectory prediction. The improved kinematics model of aircraft relative flight considering flight crew intention, aircraft true airspeed variability, and atmosphere conditions is introduced in the paper. The study is focused on improved kinematics model of aircraft relative flight position error estimation. Operational airborne separation capabilities are outlined based on the comparison between the improved and simple model of aircraft relative flight. KEY WORDS: aircraft trajectory prediction, trajectory prediction error, aircraft position prediction error, flight safety

Doris Novak, Tino Bucak, Tomislav Radišić
2009 (Vol 21), Issue 5
As part of Local Conversion and Implementation Plan which is based on the EUROCONTROL Revised Convention the Republic of Croatia has undertaken to make a plan of implementing the Basic Continuous Descent Approach procedures. This paper addresses the issue of navigational path optimization for the A-319/320 commercial aircraft within the fleet of Croatia Airlines, during the approach part of flight, which has a positive effect on fuel consumption, greenhouse gas emission and area of surface affected by noise. The experiments were carried out in real conditions, using internal sensors onboard (Flight Data Recorder) and independent GPS system. Two types of approach were tested: Continuous Descent Approach (CDA) and Step Down Approach. The implementation of CDA procedures, just for the fleet of Airbus 320/319 aircraft of the Croatia Airlines results in approximate calculation in fuel saving which amounts to 1.5 x 106 kg annually (only on Zagreb airport). In this way, the productiveness of an air carrier, which is an integral part of the traffic process along with the airports and air traffic control, is directly increased, thus fulfilling the purpose of air traffic technology research. KEY WORDS: navigational procedures, continuous descent approach, air traffic, ecology

Čedomir Dundović, Mirko Bilić, Joško Dvornik
2009 (Vol 21), Issue 5
The purpose of this paper is to show the efficiency of application of system dynamic simulation modelling when researching the behaviour dynamics of the port transhipment process, and finding the optimal solution for cargo handling with regard to the type and scope of cargo traffic, directions of movement, and pace of receiving and shipping of cargo. In view of the potential scientific implementation and verification of the hypotheses about the usage of system dynamic simulation models, the goals are multi-dimensional as they include designing qualitative and quantitative simulation models for a non-linear system, verification of the validity of the behaviour dynamics of the model, application of the simulation models, application of the parameter optimisation of the simulated process, and scientific verification of the results obtained through the simulation of the model. In compliance with the developed system-dynamic, mental-verbal and structural model, using the Powersim Studio system-dynamic flowchart of the port cargo system, in Powersim Studio simulation language, it is possible to conduct a scientific research of the dynamics of the continuous behaviour of the observed port cargo system in an experimental way, i. e. by using computers, simulating various scenarios of likely occurrences in the real world, without jeopardising it. KEY WORDS: system dynamics, modelling, transhipment process, optimisation, continued and discrete simulation

Milan Ambrož, Branko Lotrič
2009 (Vol 21), Issue 5
Research in the area of packaged tour services, provided by the national and foreign tour operators has concentrated on mutual relationships among tourist-perceived service quality, satisfaction and repurchase intentions. However, little research in this domain has been done to explain the impact of repurchase intentions of experienced tourists on the relation between perceived quality of service and their satisfaction. This model was tested using substantial data set of experienced tourists with time span of three years. While previous literature has suggested that quality perceptions impose direct effect on tourist satisfaction, this study shows that such effect is more powerful when mediated by repurchase intentions of experienced tourists. The quality of packaged tour services mediated by repurchase intentions of the experienced tourist is expected to be paramount for the retention of the tourist in the long term. KEY WORDS: repurchase intentions, quality, packaged service, services chain, tour operator, retention, tourist satisfaction.

Ivan Komar, Nenad Vulić, Radovan Antonić
2009 (Vol 21), Issue 5
Modern ships are means of transport which, during their entire operational lifespan, need to convey cargo and/or passengers in a safe and reliable way, without jeopardising their safety, and with least possible adverse impacts on the marine environment. The ship’s safety and functionality directly depend on the reliability of her propulsion system, the shafting being the essential unit of the system. The functionality of the ship’s shafting considerably depends on its correct installation. Installation of the ship propulsion shafting is an integral part of the overall positioning (alignment) procedure. Shafting alignment is performed in several stages, starting with the shaft line design, and includes calculating the elastic line and bearing loads, installation of shafting parts onboard ship in compliance with the calculation results, and verifying the alignment results. Procedures are different for ships in service and newly built ships. This paper deals with specific features of the propulsion shafting alignment that is carried out while a ship in service is being converted for a general reason. Unlike a newly built ship, an existing ship imposes additional constraints that should be dealt with in the calculation stage of the process as well as during shafting installation and alignment verification. A calculation approach for ships in service is always different, having specific features from case to case, depending on what is changed and what remains unchanged during the conversion of the ship. The same goes for the implementation and verification of the achieved results. The purpose of this paper is to underline the difference, its contribution being in suggesting the procedure to be followed in case of conversion of an existing vessel. KEY WORDS: ship in service, shafting, alignment, GAP, SAG

Danko Čurepić, Zdravko Toš
2009 (Vol 21), Issue 5
The requirements for the prompt usage of traffic infrastructure capacities define the technological frames which ensure updated maintenance and development of new traffic infrastructure capacities by implementing graphical and computer systems. Technical documentation (TD) based on the technology of geographic information systems (GIS) allows fast analysis of graphical and alphanumerical data with the aim of identifying spatial relations among various cartographic elements. The paper analyses and presents the methodological bases of building GIS with the aim of designing the traffic network topology, as well as structural and functional analysis which uses the acquired knowledge to propose concrete solutions on connecting data about the position of infrastructure facilities with their properties in the railway traffic safety. KEY WORDS: technical documentation, geographic information system, structural and functional analysis, software for technical drawing, signalling devices, railway

Milan Stanković, Zvonimir Pilih, Božidar Ivanković
2009 (Vol 21), Issue 5
Fast development of tertiary activities has deleted the borderline between the working and free time, workdays and holidays. The highways reduce the time of individual transport by personal and cargo vehicles due to higher travelling speeds, but toll collection results in time losses due to obligatory stopping of vehicles. The objective of the study presented in the paper is the exact calculation of the time losses caused by toll collection. The simulation method based on the technical characteristics of the vehicles has been combined with the analysis of the register of toll collection dynamics. Since the queuing losses at peak and off-peak periods have not been taken into consideration, the obtained values of losses are minimal. The paper considers various technologies of toll collection. KEYWORDS: travelling speed, acceleration, toll collection, assessment

Zdenko Lanović
2009 (Vol 21), Issue 4
The paper studies the complementarity of the methods from the field of traffic flow theory: methods of traffic flow intersecting intensity and the method for the at-grade intersection capacity analysis. Apart from checking mutual implications of these methods, the proportionality of mutual influences is assessed. Harmonized application of these methods acts efficiently on the entire traffic network, and not only on the intersections that are usually incorrectly represented as the only network operators. Theoretical considerations are illustrated by a practical example. KEY WORDS: traffic flow theory, theory of organization and direction of traffic flows, intersecting intensity of traffic flows, intersection capacity, optimization

Svjetlana Hess, Mirano Hess
2009 (Vol 21), Issue 4
This paper addresses the optimization possibilities of cargo operations onboard ship in order to minimize the operational costs through optimal structure of resources required. Since the setup model consists of composite objective function with several decision variables whose solution is constrained in the field Z+, the method for direct finding of optimal solution does not lead to satisfactory results. Therefore, for the solution of the problem a genetic algorithm has been developed, which yields an acceptable solution in a short time. In the given area of the possible solutions, the genetic algorithm, with variations of different crossover methods and mutation rates, gives a solution that coincides with the observed and expected results when operations of loading/unloading of general cargo ship are concerned. With the obtained structure of resources allocated in cargo operations, the minimum of operational costs is reached. KEY WORDS: ship, cargo operations, optimization, genetic algorithm

Abraham Akkerman, Jan Kudrna, Tomáš Apeltauer
2009 (Vol 21), Issue 4
A simplified modelling approach to urban commuting patterns is achieved by focusing on daytime populations rather than on commuters, or on the commuting process itself. Whereas past studies were usually economic in nature, and viewed commuting as a process within the continuum of urban space and time, the approach addressing daytime populations transforms the modelling attempt into a demographic deliberation of a binary situation where switching of values between daytime and night-time indicators in each subarea throughout a metropolis is considered. The present study shows that such a focus on diurnal change as a binary concept offers a new paradigm in conceptualizing metropolitan commuting and transportation. Under certain assumptions, rooted in recent observations of metropolitan areas elsewhere, this study conjectures an analytic function for the estimation of daytime populations in small areas throughout the metropolitan region of Brno, Czech Republic. The conjectured relationship is a logistic function that utilizes as its independent variable the average household size in each of the subareas throughout the metropolitan region. Based on the data from the Czech census of 2001, the distributions of average household size and of residential populations throughout the metropolitan region are applied in a case study illustrating the utility of the proposed approach for the estimation of daytime populations throughout the region. The iterative procedure advanced here offers considerable potential for further applications elsewhere. KEY WORDS: metropolitan commuting, urban transportation, Brno, daytime population, average household size, logistic function, small area demography

Vlatko Lipovac, Vedran Batoš, Boris Nemšić
2009 (Vol 21), Issue 4
In this paper, a solution is proposed for testing TCP congestion window process in a real-life network situation during stationary time intervals. With this respect, the architecture of hardware and expert-system-based distributed protocol analysis is presented that we used for data acquisition and testing, conducted on a major network with live traffic (Electronic Financial Transactions data transfer), as well as the appropriate algorithm for estimating the actual congestion window size from the measured data that mainly included decoding with precise time-stamps (100ns resolution locally and 1ms with GPS clock distribution) and expert-system comments, resulting from the appropriate processing of the network data, accordingly filtered prior to arriving to the special-hardware-based capture buffer. In addition, the paper presents the statistical analysis model that we developed for the evaluation whether the data belonged to the specific (in this case, normal) cumulative distribution function, or whether two data sets exhibit the same statistical distribution - the conditio sine qua non for a TCP-stable interval. Having identified such stationary intervals, it was found that the measured-data-based congestion window values exhibited very good fitting (with satisfactory statistical significance) to the truncated normal distribution. Finally, an appropriate model was developed and applied, for estimating the relevant parameters of the congestion window distribution: its mean value and the variance. KEY WORDS: protocol analysis, TCP-IP, testing, traffic congestion, statistical analysis, parameter estimation

Željko Marušić, Izidor Alfirević, Omer Pita
2009 (Vol 21), Issue 4
This article is dealing with airline industry standards regarding reliability reporting and with practical aspects of reliability program deployment within an operator’s organization. Reliability program is a tool for monitoring the effectiveness of aircraft maintenance program. Apart from being an effective tool for maintenance program development, the reliability program can bring to light flaws in aircraft design, discrepant operational procedures, discrepancies in line and base maintenance. Reliability program is also considered to provide very valuable means for achieving better operational performance (through decreased maintenance-related problems in operation) and increased flight safety. For this reason, reliability programs are mandated by the regulations for all commercial operators. Even though there is a general industry standard regarding maintenance reliability programs, it still has to be customized and optimized by each operator in order to gain the most out of it. Organizational procedures will vary significantly from one operator to another, reflecting the size and structure of the monitored fleet, size of the operator and its engineering power. As maintenance reliability program involves the application of statistic methods in finding systematic negative trends, the bigger the size of the fleet, the more accurate and reliable results can be achieved. This work is outlining the existing airline industry standards and good practice in carrying out maintenance reliability program. KEY WORDS: aircraft maintenance program, maintenance reliability program, flight safety, small airline operator

Stanislav Pavlin, Vedran Sorić, Dragan Bilać, Igor Dimnik, Daniel Galić
2009 (Vol 21), Issue 4
International Civil Aviation Organization and other international aviation organizations regulate the safety in civil aviation. In the recent years the International Civil Aviation Organization has introduced the concept of the safety management system through several documents among which the most important is the 2006 Safety Management Manual. It treats the safety management system in all the segments of civil aviation, from carriers, aerodromes and air traffic control to design, construction and maintenance of aircraft, aerodromes, those who produce instruments, equipment and parts for the needs of civil aviation and others. This paper presents and partly deals with the documents from the safety management system domain and the system implementation in Croatia with special focus on the Croatia air navigation service provider, Croatia Control Ltd. KEY WORDS: safety management system, safety, air traffic control

Savo Marković
2009 (Vol 21), Issue 4
In the existing legislative process, the Montenegrin judicature faces a series of questions imposed by the practice of arresting ships. Legislation tries to respond to them by innovating the current regulations, based on the 1977, i.e. 1998 Maritime and Inland Navigation Act (MINA), and by taking into consideration the achievements of foreign, similar jurisprudences and legislations, as well as of international conventions. The proposed solutions in the draft of the Maritime Navigation Act represent a certain change in legislative systematization of the legal institute of temporary measure of ships arrest. KEY WORDS: arrest of ships, national legislation, International Arrest Conventions

Fadila Kiso, Abidin Deljanin
2009 (Vol 21), Issue 4
Air transport industry has gradually increased its share of global passenger and freight traffic, and this trend has accelerated in the last 40 years. For the past decade, air-freight traffic growth has outpaced air passenger traffic growth by 1-2% each year. In the past, air-freight sector offered limited services, with heavy reliance on several intermediaries and a significant dependence on air passenger operations. The sector can now be characterized as a sophisticated, innovative one, relying heavily on new electronic technologies, offering a wide range of transport and logistical products through dedicated specialist freight operators. With increasing emphasis on the globalization of trade and economic activity, air-freight growth is expected to continue to outpace air passenger traffic growth. The air-freight growth is expected to be greatest in the Asian markets (intra-Asia; North America-Asia; Europe-Asia and Australasia). The process of physical distribution of freight has become a highly sophisticated operation, with increasingly greater reliance being placed on the use of new technology to assist in the movement, storage, and tracking of consignments. But transport is just one component in this logistics chain. In this paper, air-freight sector is examined in terms of its structure, organization, its role in the supply chains, the main trends in the recent period, constraints facing the sector and the future prospects in air-freight sector. KEY WORDS: air freight organization, development, trends, forecast, logistics services

Irena Ištoka Otković, Ivan Dadić
2009 (Vol 21), Issue 3
Delays belong to standard parameters used for the evaluation of any type of intersection and they are taken in the evaluation of the level of service of an intersection. Intersections with shorter delays bring about economical benefits both for the users and the community, and enable greater efficiency of a traffic system, which is becoming a significant criterion with the increasing motorization. The case studies carried out in Europe and worldwide reveal that roundabouts bring delay savings if compared with other intersections of the same operational level and nearly the same traffic volume. The paper shows the results of the comparison analysis of the roundabout and the signal-controlled intersection in the city of Osijek, Croatia. The statistical indicators have given the basis for the evaluation of delays at the observed intersections, offering at the same time the possibility to compare the analysis conclusions on the local level with the conclusions of the case studies carried out throughout Europe and worldwide. KEYWORDS: delays, roundabout, signal-controlled intersection

Srećko Favro, Mirjana Kovačić, Zvonko Gržetić
2009 (Vol 21), Issue 3
The authors of this paper have systematically studied the trends of increasing demand in nautical tourism. The increasing demand is followed by a significant increase of threats to the environment, but also to boaters and their vessels participating in nautical activities. The authors emphasise the obligation to observe safety requirements through defined and controlled procedures in marinas and at sea and implementation of international standards during the stages of organisation of nautical economy, i. e. nautical tourism with complementary activities. The authors explicate the implementation of international standards for selecting locations for marinas, construction and equipment of marinas and vessels, training of boaters – skippers, business operations of subjects and objects of nautical tourism and promotion of their services. Special attention is given to safety standards and procedures during emergencies at sea and in the ports. Each vessel is expected to have a GPS (Global Positioning System) device and a box similar to a black box in aeroplanes which could be used for reconstructing accidents. Radar systems, AIS system (Automatic Identification System) and alarm systems will minimise the time for interventions. The intervention procedures at sea are currently being determined aimed at minimising the time, but improvements are still needed. Special attention is also given to activities related to resolving crises, analysis of the existing and the potential causes and to defining of preventive actions. KEY WORDS: nautical tourism, international standards, crises

Ivica Šegulja, Ante Bukša, Vinko Tomas
2009 (Vol 21), Issue 3
The traditional marine maintenance concept based on individual equipment manufacturer’s recommendations does not represent the most efficient maintenance strategy. Suggested manufacturer’s intervals can be modified due to a great number of factors that influence the condition and the component performance. In work [1] the model for defining and adjustment maintenance strategy onboard ships was developed, assuring the required level of safety and the lowest lifecycle cost. The present model for adjusting the maintenance interval of significant items is part of this model, which has been verified on real data from thirteen years of experience. The results obtained by the model are different from the data suggested by the manufacturer. KEYWORDS: maintenance, diesel-engine propulsion system, significant items, maintenance interval adjustment, failure rate, time between failures, maintenance interval adjustment of exhaust valve

Davor Krasić, Petra Gatti
2009 (Vol 21), Issue 3
Maritime passenger demand forecasting is a task that is almost always present in the development studies of passenger ports, both due to operational and investment requirements. If a port belongs to a tourist destination, then there is a reasonable intention to use the forecasting model in order to establish the dependence between the passenger and tourist demand. Since the reliability of forecasting depends to a great extent on the quality and availability of data, the forecasting model is often a compromise between the theoretical assumptions and practical possibilities. This paper presents the approach to maritime passenger demand forecasting using a case study of the tourist destination – Poreč, which has been the strongest destination in Croatia regarding tourist traffic for many years. The presented forecasting models can serve as one of the guidelines for further study of the relations between traffic and tourism. KEY WORDS: forecasting maritime passenger demand, forecasting tourist demand, traffic and tourism

Goran Zovak, Ivo Čala, Igor Šiško
2009 (Vol 21), Issue 3
The HRN EN ISO/IEC 17020:2005 requirements have been applied to the auditing of the operation of the stations for technical inspection of vehicles which, as part of the system of technical inspections and registration of vehicles in the Republic of Croatia is carried out by the Croatian Automobile Club, based on the public accreditation issued by the Ministry of the Interior of the Republic of Croatia. The direct consequence of the application of this standard, i. e. the implementation of the quality management system is the improvement of the quality and efficiency in performing the respective activity, thus raising the level of technical roadworthiness of vehicles, i. e. traffic safety on the roads in the Republic of Croatia. KEY WORDS: supervisory/inspection bodies, quality, quality management, technical inspection of vehicles, auditing

Petar Čovo, Hrvoje Baričević, Ante Vukušić
2009 (Vol 21), Issue 3
It may be well said that the most used indicator of the quality of any technical system is reliability. Basically, this indicator shows the probability of proper technical system functioning within certain time period and under given operating conditions. To ensure that a system under construction possesses adequate given pre-defined characteristics and reliability indicators, it is necessary to plan the reliability and apply suitable methods when new technical systems are developed. Road represents an elementary traffic subsystem, as well as a technical subsystem, constructed by the society in order to meet the communication needs. Its purpose is to enable traffic system functioning. If a road is seen as a system, one can observe the features determining the structure and the principal on which its function is based. The road functioning itself is characterized by a variety of features, the most important being the management characteristic and specific social interest, categorization structure, and roadway condition. To enable smooth and safe traffic, roads should be of prescribed technical and usage levels. Reference is made specifically to road maintenance in the Primorje-Gorski Kotar County. KEYWORDS: infrastructure, terotechnology, road network, maintenance, theory of benefit

Tanja Poletan Jugović, Natalija Jolić, Zvonko Kavran
2009 (Vol 21), Issue 3
Pan-European Corridor V that passes through the territory of the Republic of Croatia, i.e. Branches VB (Rijeka-Zagreb-Budapest) i VC (Budapest-Osijek-Sarajevo-Ploče) are of extreme importance for the traffic and economic system of the Republic of Croatia and the wider European area. Taking this into consideration, this study has analysed the relevant indicators of the traffic growth, structure and dynamics of the cargo flows on the Branches VB and VC of the Pan-European Corridor V. The cargo flows, as important elements of the traffic demand have been analysed regarding the presence of competition of alternative North-Adriatic and North-European traffic routes as important element of competitive environment in fighting to attract valuable transit market of Central Europe. Based on a detailed analysis of concrete statistical data, significant conclusions are derived about: quantity, dynamics and structure of the cargo flows, current traffic demand, competitiveness of corridors on Central European transit market, expected traffic demand, and conclusions about factors and circumstances that would positively, i.e. negatively affect the growth of cargo flows, and thus also the valorisation of the analysed Branches VB and VC of the Pan-European Corridor V within the European environment. KEY WORDS: Pan-European Corridor V, branches VB and VC, cargo flows, intensity, structure, dynamics, traffic demand

Zoltán Bokor
2009 (Vol 21), Issue 3
Transport companies are facing management problems of enhancing operation efficiency at limited resources. The decision-making procedures applicable to solve such problems can be made more reliable if relevant information on basic components of business or technology processes are available. This information base can be produced by using cost and performance management methods combining financial and technology system parameters. The paper aims at summarising the research results conducted in the field of developing cost and performance controlling tools using this approach for the case of different transport companies. After explaining the main modelling principles, the experiences of empirical pilot projects are discussed. The preliminary results of these projects have proved the significance of the elaborated methodology. At the same time, it can also be concluded that the modelling tool shall be adapted to the specific circumstances of the examined transport companies before practical implementations. KEY WORDS: cost calculation, performance management, controlling

Štefica Mrvelj, Miro Cvitković, Ivan Markežić
2009 (Vol 21), Issue 2
This paper considers the aspect of dynamic routing in a circuit switched network which is not a full connected network. It also presents the theoretical considerations that affect the selection and definition of routes as well as parameters that affect the link resource capacities. In restrictions set in this way imposed by ground/ground (G/G) voice communication in ATM (Air Traffic Management) the solutions of performance for the suggested dynamic routing scheme have been achieved. KEY WORDS: ATM, GG voice communication, dynamic routing, link capacity dimensioning

Darja Topolšek, Martin Lipičnik
2009 (Vol 21), Issue 2
This paper provides a system dynamic model for reducing the number of motorway accidents due to wrong-way driving. Motorway accidents are often fatal due to high speeds. It is therefore necessary to carry out all the possible countermeasures in order to achieve adequate traffic management. One of the reasons for motorway accidents is driving in the wrong direction. Based on the analysis of the data on motorway accidents caused by driving in the wrong direction and based on the knowledge of individual project elements of junctions and slip roads, this paper will focus on this area. The possible countermeasures, presented here for preventing drivers from driving in the wrong direction on motorways drastically reduce the number of U-turn maneuvers that result in driving in the wrong direction and influence the level of safety on motorways. With the help of this model of system dynamics the countermeasures for reducing the number of such drivers will be confirmed and their effects will be shown. KEY WORDS: traffic safety, motorway, direction, (road) accidents, measures, system dynamics

Patricija Bajec
2009 (Vol 21), Issue 2
The concept and practice of traditional outsourcing is certainly not a new concept. Globalisation, competition and other market pressures have driven more businesses to consider using logistics provider to increase efficiency and effectiveness [11]. Many companies have successfully used traditional outsourcing to lower costs and have improved the bottom line. However, unless the company’s efforts are unusually good, true competitive advantage is fleeting when competitors begin outsourcing and achieving similar results [2]. Some companies have discovered even greater returns are possible and are now using advanced form of outsourcing – intelligent outsourcing or smartsourcing, to drive new revenues, quicken time-to-market, and increase innovation [2]. This shift, from traditional outsourcing to intelligent outsourcing - smartsourcing which has become a competitive advantage and is likely over time to become a competitive necessity for all, will be analysed in this paper. KEY WORDS: logistics, growth, globalization, traditional outsourcing, innovation, intelligent outsourcing - smartsourcing

Čedomir Dundović, Danko Basch, Đorđe Dobrota
2009 (Vol 21), Issue 2
Owing to ever increasing share of the natural gas in the world consumption of the power sources, the international maritime traffic with the liquefied gas is recording constant growth with even greater future anticipations. It results in the need for the construction of new LNG receiving terminals. In order to be integrated in those trends and to make provisions for additional quantities of power sources necessary for its future economic development, the Republic of Croatia is making plans for the construction of such a terminal. Successful planning and designing of LNG terminal depends on the application of appropriate methodology for the evaluation of terminal capacity. This paper gives a simulation method for the evaluation of receiving LNG terminal capacity. KEY WORDS: liquefied natural gas, receiving terminal, evaluation of terminal capacity, model, discrete simulation.

Tomislav Josip Mlinarić, Miran Pirnar
2009 (Vol 21), Issue 2
Failure to realize the schedule which is primarily reflected in train delays is the direct consequence of insufficient availability of capacities of the current railway infrastructure which are generated by low level of usable quality of the track network in general. The aim of the research presented in this paper is to determine the method of optimal interventions of the rail infrastructure managers and traffic control activities on the reduction of the influence of slow runs and line closures thus ensuring a sufficient number of rail routes for the customers’ needs and consequently higher quality realization of the schedule. The paper gives a concrete presentation of the volume of slow runs and line closures, calculation of reducing the level of railway capacities with a simulation and the result of this condition on the capacity of the concrete railway line and the proposal of a model for organizing an expert group within the traffic control activities for the fastest possible elimination of these negative phenomena. KEY WORDS: liberalization, route leasing, quality deterioration, track availability

Petr Průša, David Tilkeridis
2009 (Vol 21), Issue 2
The paper presents the strategic logistics management with emphasis on clear, accurate and effective material flow from the suppliers and internally, as well as an outline of the logistics policy for continuous improvement. The implementation of a complete Supplier Logistics Performance System is essential to support internal processes efficiency and establish a continuous improvement system according to the main logistics policy. Every company should consider such a system in order to win in the challenging field of current industry. KEY WORDS: logistics policy, logistics continuous improvement system, Electronic Data Interchange (EDI), Logistics Key Performance Indicators (LKPI)

Vinko Višnjić, Marko Pušić
2009 (Vol 21), Issue 2
The safety of road traffic in small towns in the Republic of Croatia is not at a satisfactory level. As proof, the safety of road traffic participants in the area of the town of Nova Gradiška and its wider environment has been studied and analyzed. The paper includes the available data in the period from 2000 to 2007. The analysis and the assessment of road traffic safety can be applied also to other towns and counties of the Republic of Croatia. Having in mind that there are 531 settlements in the Republic of Croatia (119 towns and 412 districts), out of which only 78 are larger than 10,000 inhabitants or 14.69% of the total number, which means that the analysis could be made for any settlement in the Republic of Croatia. The road traffic safety assessment was conceived according to the modified Smeed model which may be applied for any settlement or town. The road traffic safety analysis has led to the conclusion that safety of all the traffic participants is endangered. This paper provides solutions about what has to be done in order to reduce the danger to all the road traffic factors. KEY WORDS: drivers, traffic, traffic accidents, safety and small towns

Ljupko Šimunović, Ivan Bošnjak, Sadko Mandžuka
2009 (Vol 21), Issue 2
The paper gives an overview of the past development and implementation of Intelligent Transport Systems in pedestrian traffic. Starting from recent development projects and methodological approaches to the development of ITS, an overview of the existing technologies of implementing ITS in pedestrian traffic is given, and some solutions are proposed that would be feasible in the Republic of Croatia, as well as in other transition countries. As the most significant functions of integrated systems within ITS, the possibilities are presented of locating pedestrians in the network, pedestrian guidance (especially the blind and low-vision persons as well as persons in wheelchairs), provision of on-trip information, etc. Special focus is on the area of pedestrian protection in traffic (avoidance of accidents) using devices fitted onboard vehicles and embedded in road infrastructure. The significance of timely integration of the pedestrian traffic in designing the future ITS architecture has been indicated. KEY WORDS: intelligent transport systems (ITS), pedestrian traffic, pedestrian guidance, real-time information, traffic safety

Darja Topolšek, Martin Lipičnik
2009 (Vol 21), Issue 2
This paper provides a system dynamic model for reducing the number of motorway accidents due to wrong-way driving. Motorway accidents are often fatal due to high speeds. It is therefore necessary to carry out all the possible countermeasures in order to achieve adequate traffic management. One of the reasons for motorway accidents is driving in the wrong direction. Based on the analysis of the data on motorway accidents caused by driving in the wrong direction and based on the knowledge of individual project elements of junctions and slip roads, this paper will focus on this area. The possible countermeasures, presented here for preventing drivers from driving in the wrong direction on motorways drastically reduce the number of U-turn maneuvers that result in driving in the wrong direction and influence the level of safety on motorways. With the help of this model of system dynamics the countermeasures for reducing the number of such drivers will be confirmed and their effects will be shown. KEY WORDS: traffic safety, motorway, direction, (road) accidents, measures, system dynamics

Čedomir Dundović, Danko Basch, Đorđe Dobrota
2009 (Vol 21), Issue 2
Owing to ever increasing share of the natural gas in the world consumption of the power sources, the international maritime traffic with the liquefied gas is recording constant growth with even greater future anticipations. It results in the need for the construction of new LNG receiving terminals. In order to be integrated in those trends and to make provisions for additional quantities of power sources necessary for its future economic development, the Republic of Croatia is making plans for the construction of such a terminal. Successful planning and designing of LNG terminal depends on the application of appropriate methodology for the evaluation of terminal capacity. This paper gives a simulation method for the evaluation of receiving LNG terminal capacity. KEY WORDS: liquefied natural gas, receiving terminal, evaluation of terminal capacity, model, discrete simulation.

Jelenko Švetak
2009 (Vol 21), Issue 1
The paper discusses the ship domain zone or ship navigationsafety area. The navigation safety area around the ship hasbeen the object of research of many authors. Different variantsand algorithms have been suggested and the most popularamong them are as follows:- navigation safety area around the ship being observed by herown devices, presenting information of the danger of possiblecollision directly on the bridge;- navigation safety area around the ship when regulating hermovement by means of Vessel Traffic Se1vices.The article presents an algorithm for determination andplotting of the navigation safety area, which has the followingadvantages:- the algorithms give an instant solution to the problem ofevading one or more dangerously moving targets;- the calculation may apply the ARPA (Automatic RadarPlotting Aids) algorithm, which does not prevent the navigatorfrom keeping watch.The above mentioned algorithm allows simultaneous plottingof information about the situation around the ship and thedata for probable manoeuvring.

Željko Kurtela, Pavao Komadina
2009 (Vol 21), Issue 1
Having identified all the dominant factors and having puttogether a mosaic of all the factors resulting from a ship 's voyage,as well as a number of differently dimensioned criteria, theharmfulness evaluation method for water ballast managementon board has been elaborated. By careful analysis of the impactfactors to which status elements are adjoined, by the assignmentof harmfulness levels to the status elements, by determiningdifficulty factor values, by introduction of treatment methodsi.e. exchange of water ballast, certain characteristic managementscenarios according to ship type are developed. Cumulativescenarios provide insight into the total harmfulness ofwater ballast management. The introduction of a comprehensiveapproach results in the development of different scenariosapplicable to all ships. The established harmfulness evaluationmethod for water ballast management is applicable to all shiptypes, and it has been tested on various types of ships that weredischarging ballast in various ports worldwide.

Katalin Tanczos, Arpad Torok
2009 (Vol 21), Issue 1

The nowadays applied different macro models or parts ofthose, which describe the urban environment, can originate in afour-step modelling process. The paper focuses on the trip distributionprocess (the 2'd step) because of its significant calibrationrequirements. Therefore, it is possible to make the entiremodelling process more reliable (dependent upon the reliabilityof the available databases ).


Vlatko Lipovac, Vedran Batoš, Antun Sertić
2009 (Vol 21), Issue 1
This paper studies how end-to-end application peiformance(of Electronic Financial Transaction traffic, in particular)depends on the actual protocol stacks, operating systemsand network transmission rates. With this respect, the respectivesimulation tests of peiformance of TCP and UDP protocolsrunning on various operating systems, ranging from Windows,Sun Solmis, to Linux have been implemented, and thedifferences in peiformance addressed focusing on throughputand response time.

Libor Švadlenka, Aleksander Chlan
2009 (Vol 21), Issue 1
The paper deals with the postal sector control. It resultsfrom the control theory and proves the justifiability of control inthe postal sector. Within the price control it results from E U Directive97!67/EC requirements on this control and states individualtypes of price control focusing on ineffective price controlcurrently used in the Czech postal sector (especially withindomestic services) and proposes a more effective method ofprice control. The paper also discusses the principles of the proposedmethod of price control of the Czech postal sector. It describesconcrete fulfilment of the price control model resultingfrom the price-cap and tariff formula RP I-X and concentrateson its quantitative expression. The application of the proposedmodel is carried out for a hypothetical period in the past (in orderto compare it with the current control system) for letteritems tariff basket.

Juraj Vaculik, Ivan Michalek, Peter Kolarovszki
2009 (Vol 21), Issue 1
The paper deals with RFID (Radio Frequency Identification)implementation and utilization within supply chain managementand also includes the economic feasibility of rollingout RFID. The members of the supply chain networks- suppliers,manufacturers and distributors - will operate independentlyfrom one another and according to their own agendas.This type of unmanaged network, howeve1; results in inefficiencies.The manufacturer might have a goal of maximizing productionin order to minimize unit costs. Clearly, all members ofthe supply chain stand to gain by coordinating their efforts toimprove efficiency and overall supply chain performance. Thisarticle is divided into three parts: Supply chain, Economic feasibilityof rolling out RFID and Processes of Supply chain management.

Marina Zanne, Mirjana Grčić
2009 (Vol 21), Issue 1
Natural gas is relatively cheap, environmentally friendlyand energetically efficient fossil fuel that is gaining in attractivenessdaily as it can be used in many sectors. As not all consumerscan be reached by pipelines the technique of transp01tingnatural gas in the liquefied form has been developed at the beginningof 20th century but it was only in 1959 that the firstoverseas transport of liquefied natural gas ( LN G) occurred. Inthe fifty years of operation LNG shipping has shown immaculatesafety records. LNG tankers can be described only in superlatives;they are without any doubt the most sophisticated and·expensive ships that sail around the globe, they demand specialattention when navigating to or out of harbours and need to bemanned with the most educated and experienced crew. LNGmarket is expanding and changing; demand is surpassing theproductivity, new importing and exporting countries appear,LNG fleet is growing in capacity and number at high pace, exploitationcontracts for the ships are being modified giving theopportunity for new companies to enter( . .. ). The paper givesan overview on liquefied natural gas market and the historic developmentof LNG shipping. It focuses on the recent boom inLNG shipping and emphasises questions concerning the safety,crewing and exploitation of the LNG tankers in the future.

Robert Muha, Drago Sever
2009 (Vol 21), Issue 1
The introduction of contemporary procedures to fleet managementprocesses has recently changed the work planning andsupervision of driver's work activities. Tendencies to control theimplementation of driver's work have been present in modemprofessional practice for quite a long time; however, the equipmentavailable on the market limited its implementation. Theintensified development of digital tachographs has, in technicalterms, ensured such equipment considerably before the legislativegroundwork was prepared for its practical implementation.The Commission Regulation (EC) No. 561!2006 (implementationof Social legislation relating to Road Transport) does notbring any essential novelties in terms of permitted workload.Consistent monitoring of drivers activities, made possible bydigital tachographs, will have impact on the existing workingmethods. The topic of the present paper is in deep analysis ofthe impact of the mentioned regulation with special emphasison the conditions for the regulation of the current stage of driverswork and on the expected consequences. The essential imp011ancelies on the expected change in the mentality and approachto planning the driver's activities in the transport processon the part of the ea n·ier: the outcome will eventually resultin the efficiency of each individual canier.

Published by
University of Zagreb, Faculty of Transport and Traffic Sciences
Online ISSN
1848-4069
Print ISSN
0353-532
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