The occurrence of road accidents due to a pavement surface with inadequate roughness is an alarming issue. This problem involves not only the design, construction and maintenance of road pavements, but also the properties of the materials used in the asphalt mixes, traffic volume and vehicle speed, as well as tire characteristics, human factors, environmental conditions and many other contributing elements. As a result, there is a growing awareness of these problems and adequate measures have to be taken by road administrations in order to improve traffic safety. For the design, construction and maintenance of a modern road network, along with strength and sustainability, skid resistance has become an integral part of a safe and efficient road system. With the increase in traffic speed and volume, the road pavements built today must have initial and continuous qualities of high skid resistance. It is a well-known fact that the pavements skid resistance is reduced primarily by mechanical wear and polishing due to traffic action; however, to what extent the friction characteristics are diminished and the other causes and effects of this reduction are problems that road engineers have to face. Although the automotive and tire industries have contributed greatly to the research and development of skid-resistant road pavements, it is quite obvious that most of the improvements will go to pavements. In the following, the paper will focus on establishing the roughness criteria that can be applied from the early stages of the construction of a road infrastructure, by selecting those materials and techniques that lead to a high level of roughness and thus traffic safety. Also, the paper presents the results of recent experimental studies undertaken to determine the road roughness, using the microtexture as well as macrotexture criteria, conducted in Romania on the national roads DN 2 km 212 + 000 and DN 15 km 290 + 870.
Journal section: TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT
A prototype of a system for segmenting images of trains and wagons has been developed. Video cameras and specialized websites are used as the source of the original images. Median filtering of images and increase of their local contrast is carried out. The contours of the objects were calculated using the Sobel and Canny methods. Image segmentation is performed by the method of contour lines. As a result of the processing on the images of trains and wagons, meaningful areas (segments) were identified, for example, windows, headlights, etc. Detection of content areas of the object is performed using fuzzy membership functions. The hardware and software implementation of the computer system is made in Python using scipy and scikit-fuzzy libraries, the Google Colab cloud platform and Raspberry Pi 3B+ microcomputer.
The activity of snow removal on public roads is of particular importance for ensuring road transport in winter and implicitly for maintaining a stable, predictable and efficient economic and social climate. The organization of road snow removal is usually done by the local public authorities, through the public road administrator, varying depending on the geographical and climatic location of the road site. In Romania, the snow removal activity is regulated by the “Regulation on preventing and combating snow on public roads”, indicative AND 525-2013, developed by the National Company of National Highways and National Roads in Romania. The snow removal activity is usually performed on the basis of a service contract and is temporary, depending on the evolution of meteorological phenomena and climatic zones.
The actions to prevent and combat the consequences of dangerous meteorological phenomena are carried out according to their intensity on the following phases, as follows: prevention of icing formation and its neutralization, spreading of anti-skid material and snow removal. The preventive spreading of the anti-skid material is recommended to be done first on the entry / exit arteries in / from the localities. The activity of mechanical cleaning of public roads (streets, bridges, alleys, roundabouts) of snow with blade machines is performed when the snow layer exceeds the thickness of 5 cm. The activity is carried out by successive passages, starting from the axis of the road to the curb, until the complete removal of the snow layer.
This article analyzes examples of good traffic management practices in several European cities. The practices analyzed relate to providing more accurate information about public transport arrivals, optimizing demand for crosswalks, reducing congestion in urban areas, and reducing demand for trips to parking lots in the city center. Smart mobility projects such as CEKOM Connected Traf fic create high-quality urban transport solutions and promote innovative, sustainable, clean and energy-efficient transport modes. The aim of this paper is to present the positive results of different traffic management methods that lead to better traffic flow, less congestion, lower primary energy consumption and less pollutant emissions.
The activities of this scientific research project are related to the development of innovative urban and multimodal solutions in the city of Rijeka. The primary outcome indicator will be a platform for aggregating data for urban mobility and transport decision making. The scope of the platform envisions more efficient use of public-private infrastructure, resources, and assets in the field of transport. In addition, it was necessary to accurately measure traffic, meteorological and environmental parameters in the city of Rijeka to protect the environment, increase safety and achieve sustainability of the transport system in the urban area.
As part of the research activities of the Connected Traffic project, a prototype solution for traffic simulations has been developed. The aim of the simulations is to show how the use of innovative methods in the context of intelligent solutions can manage traffic in urban areas. The purpose of the simulation is to test innovative scenarios and standard operating procedures for decision support.
The greater interest of people living in urban areas has been accompanied by an increase in demand for motorized movements and other forms of active movements in these areas. As a result, traffic problems have been increased extremely for these road users both in terms of the quality of movement and safety. This research is focused on identifying factors related to the quality of motori zed and nonmotorized movements in urban areas, a particular case study of the municipality of Fushe Kosova, and the design of a model for traffic optimization in urban areas. The current approach to prioritizing the solution of motorized traffic problems, especially in d eveloping countries, has proved ineffective because, in the absence of addressing other mobility requirements (pedestrian, cyclist mobility), road users have been encouraged more to use this form of transport, leaving no room for other alternatives. The research aims to apply advanced methods for handling and managing traffic problems based on the principle of inclusion and building a model for optimizing traffic operation based on a specific case. The model is built using the programming language “Synchro,” which enables the analysis, optimization, and simulation of all forms of transport: motorized traffic, movement of pedestrians and cyclists in the road network planned following these requirements. Obtained results show the advantages of using different forms of transport depending on the selected concept and the priority of certain forms of transport. The summary results and their comparison in terms of quality for different time intervals, including the different conditions of access to urban areas, are presented in tabular forms.
The analysis of each traffic accident is carried out based on recorded traces at the scene of the traffic accident and the damage caused to vehicles. One of the basic parameters in the analysis of traffic accidents is the mutual position of the vehicle at the time of the collision. To define the collision position of the vehicle, it is necessary to determine the intensity and compliance of the vehicle damage. The development of photogrammetry has enabled the creation of 3D models based on which the intensity and mutual compliance of vehicle damage can be more clearly shown, which increases the relevance of the determined collision position of the vehicle. Accordin gly, this paper will present the process of creating 3D models of damaged vehicles and will analyze all the possibilities of applying photogrammetry in defining the collision positions of vehicles.
The scope of this paper is using Dijkstra algorithm in Python to get the urban transport optimization one step further, by finding the best route, besides analysing the shortest one. Studying urban transport routes has been first analysed by Dijkstra algorithm taking into consideration two parameters, the number of stations and distances between stations. After this, the code of Dijkstra algorithm has been implemented in Python, adding the demand for travelling in each station.
Comparative Analysis of Methods for Defining the Speed of the Vehicle in Vehicle- Pedestrian Collisionspg(s) 71-76
Pedestrians are the most vulnerable road users and traffic accidents involving pedestrians are the most complex type of traffic accident to analyse. The paper describes the kinematics of traffic accidents involving pedestrians and presents statistical data on pedestrian traffic accidents. The main element which needs to be calculated regarding a pedestrian collision is the impact speed of the vehicle involved in the collision. This paper aims to present various models of vehicle impact speed calculation. As a part of this paper, several crash tests were conducted using a pedestrian dummy to determine the reliability of the models. Additionally, the PC-Crash simulation software was also used to calculate the impact speed of the vehicle.
The paper deals with the development of the unaccompanied combined transport (UCT), in Romania. Firstly, it presents statistics and performs a quantitative analysis, depicting a sharp decline of the UCT after 1990, its low weight in the total freight transport volumes and the main characteristics of the domestic traffic which has had a higher weight than in the neighbouring countries and is almost completely connected with the Port of Constanta. The qualitative analysis indicates a great weight of the empty boxes (generating higher costs and prices), the disappearance of several type of services during the time and the fact that the Port of Constanta has not become a real engine for UCT yet. The paper identifies as reasons for these evolutions the changes in the economy, the cancelation of the support measures implemented before 1990, the route competition, the competition with other ports at the Black Sea, the constraints for the transit through the Bosphorus Strait and the lack of practical support measures. It is interesting that the policies and the strategies before and after 1990 are practically identical, but the measures implemented before 1990 are not compliant with the European legislation. Secondly, th e paper performs a comparison between the UCT with rail legs and the road transport. The analysis depicts several structural, technical, and operational issues (poor status of the railway infrastructure and container terminals, the charges for the use infrastructure that are higher in the railway case and the investments in the roads) making UCT not attractive on the market. On the other hand, the calculations based on the method used in the Marco Polo Programme, respectively using the EcoTransit application indicate lower external costs and important savings in CO2 and other polluting gases. Thirdly, the paper deals with the possible support measures, emphasizing that the measures implemented in Austria could be models for the Romanian authorities. European legislation related to the state aids also need s revisions, so that it would not embarrass the transport policies. The main conclusion is that UCT could develop only if subsidies and other appropriate support measured would be implemented.
The acceptance and popularity of formal modeling is increasing in the development of safety-critical railway interlocking systems, because it allows the specification of the system’s functionality using mathematically rigorous rules. The goal of the research described here is to introduce a simple, easy-to-learn, and useful UML (Unified Modeling Language) subset that supports railway engineers in developing the functionality of system elements at the system planning level. The selection of this UML subset is based on our practical experience. We examine the properties and limitations of this subset through a case study using the Yakindu Statechart Tools. The components specified with the proposed UML subset can be easily transformed into timed automata that we studied using the UPPAAL framework. In the paper, we also present the UPPAAL model for the case study. We are currently working on the implementation of a transformation using the UML subset presented in this paper, which makes it possible to generate formal models from Yakindu to UPPAAL in an automated way.
We live in a time of the Covid pandemic, when losses are being noticed in the car industry. Experts state that stabilization of the market is not expected before 2023. Data from the European Automobile Manufacturers Association (ACEA) showed that for the first time in 2021, hybrid electric cars were equalized with “diesels” on the European Union market. Last year, 1.901.239 new hybrid electric vehicles were registered on the common market. In April 2021, our capital Belgrade was awarded for the best Urban Mobility Plan. Our city has increased the safety of traffic participants, given priority to pedestrians and cyclists, reduced emissions and improved energy efficiency, while expanding pedestrian zones. The National Association of Autonomous and Electric Vehicles has launched a project aimed at increasing environmentally friendly traffic in Serbia. Eco 2 line of electric buses works in Belgrade from January 2022. And in Serbia, parts for Audi, Porsche and BMW will be produced in the “Motherson” factory, which was opened at the end of November 2021.
The aim of the article was to analyze the impact of lockdowns carried out during the Covid-19 pandemic in Slovakia in the years 2020 and 2021 on changes in public transport utilization in a selected locality. The sample city was the city of Košice in Slovakia and the sample contained data about the number of transported persons by public transport in this city during single days in the years 2018, 2019, 2020, 2021.
We created weekly time series from line graphs compiled for separate years. Subsequently, we analyzed the dynamics of individual time series using calculations of absolute and relative increments, basic indices, growth coefficients, absolute increment and total growth coefficient, and we modeled trends in time analysis and exponential adjustment for the observed years. We compared the years before the pandemic (2018, 2019) with the years most affected by the Corona crisis (2020, 2021). We evaluated the obtained data in the context of the timeline of ongoing lockdowns.