Vol. 26 No. 6 (2014)
Hedvika Kovandová, Robert Válka
2014 (Vol 26), Issue 6
The paper deals with safety of transport from the point of view of an important social problem, which are accidents at railroad (including tramway) and road level crossings, which means compatibility of rail and road vehicles crash. The scale of such accidents can be very wide. Regarding the statistics and frequency of accidents particularly at railway level crossings and tramway level crossings, a collision simulating the collision of a tram and passenger car was experimentally carried out. The experiment took place at the site of testing laboratory of Rail Vehicles Research Institute in Cerhenice. The experiment was conducted with a passenger car Škoda Superb of the first generation that was exposed to two collisions from both sides. Firstly by the impactor for tram headstock tests and secondly by the tram headstock itself. Both the impactor and the headstock were placed on the experimental vehicle for tests of passive safety of rail vehicles. Various speeds were chosen so that the passenger car could be used for two subsequent experiments without the influence on properties of skeleton´s supporting structure.
Zhizhou Wu, Li Zhao, Jian Sun
2014 (Vol 26), Issue 6
Traffic conflicts among right-turn vehicles (RTVs), non-motorized vehicles (NMVs) and pedestrians were examined for urban signalized intersections with exclusive right-turn lane. This study proposed an approach to dynamically calculate the duration of the prohibited right-turn for vehicles by using a measure called the Degree of Clustered Conflict (DCC). The process of DCC control includes: 1) quantitative calculation of DCC value in the conflict area; 2) establishing the general cost model that combines the delay and conflict indicators; and 3) applying the DCC-control time model to control RTV in real time. Based on these, the paper presented a general approach of detailed dynamic on-line signal control process of RTV. Finally, the RTV control process was programmed based on VISSIM simulation to evaluate the control effectiveness. The results showed that the general cost (weighted summation of delay and conflict) of the RTV control decreases rapidly compared with non-control, fixed control and full control (drop of 58%, 35% and 42% under small flow conditions and 70%, 59% and 17% in the large flow conditions, respectively). The method not only improved the operation efficiency, but also reduced the potential safety risks among traffic participants when vehicles turn right at intersections.
Ishtiaque Ahmed, Suleiman Abdulrahman, Mohd Rosli Hainin, Sitti Asmah Hassan
2014 (Vol 26), Issue 6
Transportation planners need to estimate the trip generations of different land use types in the travel demand forecasting process. The Trip Generation Manual of Malaysia, similar to the Trip Generation Manual of the Institute of Transportation Engineers, USA, provides the trip generation rate at “Polyclinics” as a function of the Gross Floor Area. However, the data for this rate have no line of best fit resulting in the lack of confidence in the prediction. This study considered ten locations in Malaysia and verified the significance of different parameters, i.e. Number of Doctors, Number of Staff, Gross Floor Area and Density of Similar Clinics within 0.5 kilometre radius in Johor Bahru, Malaysia. The study developed regression equations for estimating the peak hours and daily trips at polyclinics in terms of “Number of Doctors”. The developed models can be used in estimating the number of trips generated by the polyclinics in Johor Bahru, Malaysia.
Qingyang Xu, Ning Wang
2014 (Vol 26), Issue 6
Recently, ship collision avoidance has become essential due to the emergence of special vessels like chemical tankers and VLCCs (very large crude carriers), etc. The information needed for safe navigation is obtained by combining electrical equipment with real-time visual information. However, misjudgements and human errors are the major cause of ship collisions according to research data. The decision support system of Collision avoidance is an advantageous facility to make up for this. Collision risk evaluation is one of the most important problems in collision avoidance decision supporting system. A review is presented of different approaches to evaluate the collision risk in maritime transportation. In such a context, the basic concepts and definitions of collision risk and their evaluation are described. The review focuses on three categories of numerical models of collision risk calculation: methods based on traffic flow theory, ship domain and methods based on dCPA and tCPA.
Victor Cantillo, Miguel Jaller, Jose Holguín-Veras
2014 (Vol 26), Issue 6
Freight transport modelling at interregional scale is relevant for planning issues. However, freight modelling processes are complex because it is not easy to define the relevant variables in the analysis, and to obtain the required information on freight movements through the network. These facts raise the need to adapt the modelling framework to each context.
This paper proposes a strategic national freight transport modelling framework developed as a variant of the traditional four-step modelling process with additional steps to estimate traffic flows from freight flows and to consider empty trips. The country of Colombia is used as the case study to implement and calibrate the proposed model. The data, data sources, and modelling methodologies used for each step are explained. In addition, data limitations and measures taken to complement the available data are discussed. From the implementation, the authors identify a set of advantages derived from the modelling approaches considered and suggestions for improvement.
Elen Twrdy, Andrej Androjna, Marko Pavliha
2014 (Vol 26), Issue 6
In the modern world, the sea is one of the most important resources for the economy and welfare of the country that has access to it and so is the sense of security. Meeting today’s security challenges requires a wide spectrum of civil and military instruments. It calls for regular coordination, consultation and interaction among all actors involved, and it requires a national multifunctional Structure.
The paper presents the search for new systematic forms to ensure adequate maritime security and safety at sea. Based on the research on successfully organized similar foreign institutions in relation to the national security institutions in the maritime domain the Coast Guard model of the Republic of Slovenia has been designed. The model could significantly improve the level of efficiency and consistency of national authorities in the area of control, security and safety of the territorial sea and rationalize expenditures. Implementing the proposed model and placing it in the national security and defence system, is a challenge and also a need.
Diana Božić, Ratko Stanković, Kristijan Rogić
2014 (Vol 26), Issue 6
Raising the service level and developing new logistic services require better understanding of logistic processes and possibilities of optimization. Different methodologies have been used for that purpose, while the application of Business Process Management (BPM) methodology is outlined in this paper. Identifying parts of logistic processes that could be optimized is facilitated by applying BPM methodology. It also enables more accurate quantification of impacts of the changes introduced in a particular process or activity on the processes as a whole and to other interacting processes. The application of BPM methodology is demonstrated in the case study, where a solution for logistic processes optimization is suggested and the prospective outcomes are simulated. The results of the logistic process comparative analysis have indicated a synergic effect of different improvements in sub-process on the effectiveness of the process as a whole, both on the operative and managerial level. The respective changes in workload distribution among interacting logistic processes have been quantified according to the same methodology.
