Journal of Road and Traffic Engineering

Analysis of the impact of incoming speeds on roundabout conflicts using microsimulation modelling

Irena Ištoka Otković — 2026-10-03

This study investigated the influence of incoming vehicle speeds on the frequency, typology, and severity of vehicle‑to‑vehicle conflicts at a single‑lane roundabout, employing microsimulation modeling and the Surrogate Safety Assessment Model (SSAM). The roundabout model was held constant in terms of geometric design, and no variations in traffic demand were introduced. Incoming speeds between 30 and 70 km/h, representative of typical operational speeds in urban networks, were systematically evaluated. The findings show that higher incoming speeds increase intersection throughput and enhance operational performance, whereas safety performance remains more favorable at lower speeds. Although no clear functional relationship was observed between incoming speed and the total number of conflicts, a consistent increase in conflict severity metrics (TTC, PET, MaxS) was recorded with rising speeds, indicating elevated interaction risk. These results underscore that the conflict count alone is insufficient for assessing roundabout safety. A comprehensive evaluation requires the integration of multiple complementary indicators that jointly capture both the frequency and severity of surrogate safety events.

Building An E-Scooter Safety Culture: Temporal-Situational Crash Profiles and Data-System Readiness in Serbia

Miloš Pljakić — 2026-10-03

E-scooter safety is framed as a problem of injury severity or infrastructure, although persistent risk-taking also reflects the norms and practices through which a new mode is integrated into traffic. This study examines what police-reported crash patterns can—and cannot—reveal about e-scooter safety culture in Serbia. The national database contained 282 crashes recorded between 22 July 2023 and 26 December 2025; the primary analysis used 243 crashes from the complete calendar years 2024–2025. Temporal, seasonal and site variables were analysed descriptively and by multiple correspondence analysis followed by Ward clustering. Crash severity and year were excluded from clustering and compared between profiles. The database was also audited against behaviour and compliance domains identified in the literature and Serbian regulation. Three profiles emerged: weekday warm-season mobility (50.6%), spring daytime mobility (27.2%) and weekend/night-time mobility (22.2%). KSI proportions ranged from 19.7% to 25.9% and did not differ between profiles. The audit found six directly available and two derivable indicators, while fourteen essential indicators—including helmet use, alcohol, speed, passenger carriage and vehicle conformity—were absent. Crash records can guide context-specific prevention, but direct monitoring of e-scooter safety culture requires standardised behavioural fields, exposure data, observational surveys and linkage with health records.

Technology of Concrete and Asphalt Construction Works under Winter Conditions

Nazim Manic — 2026-10-03

Concrete and asphalt construction works under low-temperature conditions represent significant technological and energy-related challenges due to the adverse effects of winter conditions on cement hydration, early-age concrete strength development, and the proper placement and compaction of asphalt mixtures. This paper analyzes temperature regimes during the production, transport, and placement of concrete and asphalt mixtures, as well as thermal protection methods applied under winter conditions. Special attention is given to the energy requirements for heating concrete components, including heat balance calculations and the influence of curing temperature on the development of relative concrete strength. Thermal protection methods, including the thermos method and the application of thermoactive formwork systems, are also analysed. For asphalt works, heat losses during the transport and placement of asphalt mixtures were investigated using the “MultiCool” software package. The results indicate that winter conditions lead to intensified cooling of asphalt mixtures and a reduction in the available time for adequate layer compaction.

Contemporary Concepts of Transport Planning and Sustainable Urban Mobility

Miroslav Đerić — 2026-10-03

Contemporary urban development is characterized by increasing population mobility, rising motorization, and the negative impacts of transport on quality of life and the environment. In response to these challenges, the concept of sustainable urban mobility has been developed, integrating transport and spatial planning, environmental protection, and socio-economic development. The aim of this paper is to analyze contemporary transport planning concepts in the context of sustainable urban mobility, present European experiences, and assess the possibilities for their implementation in Bosnia and Herzegovina. The research applies methods of scientific literature review, analysis of the European Union's strategic documents, and a comparative analysis of best practice examples. Particular attention is devoted to Sustainable Urban Mobility Plans (SUMPs), including an analysis of the experiences of Vienna, Copenhagen, Ljubljana, and Barcelona. The results indicate that successful sustainable mobility requires integrated planning, institutional coordination, the development of alternative transport modes, and continuous monitoring of outcomes. In Bosnia and Herzegovina, the greatest potential lies in improving public transport, promoting active mobility, implementing intelligent transport systems, and strengthening institutional capacities.

Optimization of Station Location Selection in a Bike-Sharing System

Nikola Barać — 2026-10-03

A bike-sharing system, as a form of shared mobility, offers the possibility of renting publicly available bicycles. Shifting users from private vehicles to shared mobility, in this case a bicycle, has the potential to reduce traffic congestion and greenhouse gas emissions in cities. The efficiency of station-based bike-sharing systems heavily depends on the spatial arrangement of stations. From the user's perspective, it is desirable to have as many stations as possible, while the system operator aims to minimize the number of stations to reduce costs. The goal of this paper was to present a procedure for solving the station location problem in bike-sharing systems. The quality of the obtained solutions was evaluated using the average distance traveled by users and the percentage of users served. The problem was solved using single-objective optimization methods, as well as a multi-objective optimization method, which yielded a set of Pareto optimal solutions. From the perspective of decision-makers, this approach offers significant advantages in terms of decision-making flexibility. The procedure was tested on the Belgrade transportation network.

The Role of Patents and Innovations in the Development of Modern Transportation

Aleksandar Trifunović — 2026-10-03

Patents and innovations represent one of the key drivers of modern transportation development. This paper analyzes global and national trends in the field of patents, with a particular focus on intelligent transportation systems, autonomous and connected vehicles, traffic management systems, vehicle safety, and environmentally sustainable technologies. The results show a constant global increase in patent applications, especially in the domain of digitalization and the integration of information technologies with transportation solutions. In Serbia, 9,480 applications for industrial property rights were submitted in 2024, including 326 patent applications, which indicates a stable but limited level of technological innovation. While a significant increase in trademarks and industrial designs has been recorded, the number of patents remains modest compared to global trends. The study concludes that patents are not only a legal protection instrument but also a mechanism that enables improvements in traffic safety, efficiency, and sustainability. The national context highlights the need for stronger support of research and development activities in order for Serbia to reduce the innovation gap compared to leading world economies.

Analysis of Efficiency and Quality of Urban Public Transport in Banja Luka with a Proposal for System Improvement

Radenka Đekić — 2026-10-03

This paper analyzes the condition and performance of the urban public transport system in Banja Luka, with a particular focus on service quality, reliability, capacity, and user satisfaction. The research is based on an empirical analysis of data collected through a survey of 500 public transport users, which identified key issues in system functioning, including vehicle overcrowding, partial user dissatisfaction, and the need for network improvement. Based on defined research hypotheses, the study examines the relationship between transport system organization and user satisfaction, as well as the impact of service availability and capacity on mode choice. Based on the obtained results, a system improvement model is proposed through the introduction of a new line connecting key residential and industrial zones of the city. The proposed solution contributes to increased efficiency, reduction of traffic congestion, and promotion of public transport as a sustainable mode of urban mobility. The paper contributes to a better understanding of the challenges of urban public transport in medium-sized cities and provides a basis for further improvement of transport policies aimed at sustainable urban development.

Analysis of the Characteristics and Attitudes of Taxi Transportation Users in Urban Areas

Anđela Dinić — 2026-10-03

Taxi transportation represents an important component of the urban passenger transport system, characterized by a high level of accessibility, flexibility, and the ability to adapt to users’ individual needs. The aim of this study is to analyze the characteristics of taxi transportation use, as well as users’ attitudes and expectations regarding service availability, frequency of use, trip purpose, waiting time, travel distance, and taxi service prices. The research was conducted through an online survey covering respondents’ demographic characteristics, information on driving licence ownership, and habits related to taxi transportation use. A total of 157 respondents participated in the study, and the collected data were analyzed using descriptive statistics. The results indicate that respondents generally use taxi transportation occasionally, most frequently for going out at night, commuting to work, and traveling to other cities. Most respondents consider a waiting time of up to 5 minutes acceptable, while a waiting time of 6 to 10 minutes is most commonly considered the maximum acceptable waiting time. Taxi transportation is predominantly used for shorter trips, although a considerable proportion of respondents also reported using taxi services for longer journeys. A particularly significant finding is that the majority of respondents (70%) consider taxi service prices to be high. The results indicate that users recognize taxi transportation as a flexible and convenient mode of transport; however, the cost of the service represents one of the key factors that may influence the frequency of its use. This study provides a basis for a better understanding of users’ needs and for improving the quality and accessibility of taxi transportation in urban areas.