Hrvoje Pilko

Given the high risk of severe accidents at level crossings (LCs), this study examined legal and illegal crossings by pedestrians and cyclists at a high-traffic LC in Zagreb, Croatia. Survey data and field observations were collected to identify reasons for risky behaviour. Behaviour was observed under normal conditions and in the presence of various safety measures in order to identify measures that can reduce risky behaviour. Results show that the presence of police officer at the LC was most effective at reducing illegal crossings, while the presence of cameras contributes significantly as well, especially after safety educational campaign when illegal crossing decreases for 59.23%. We can assume that in future the improvement regarding human behaviour on LC could be made with cameras on LC and more frequent educational campaigns. This is the first reported use of field survey and video surveillance methods to analyse user behaviour at LCs in Croatia.

Building safe and effective roundabouts requires optimizing traffic (operational) efficiency (TE) and traffic safety (TS) while taking into account geometric factors, traffic characteristics and local constraints. Most existing simulation-based optimization models do not simultaneously optimize all these factors. To capture the relationship among geometry, efficiency and safety, we put forward a model formulation in this paper. We present a new multi-criteria and simultaneous multi-objective optimization (MOO) model approach to optimize geometry, TE and TS of urban unsignalized single-lane roundabouts. To the best of our knowledge, this is the first model that uses the multi-criteria decision-making method known as analytic hierarchy process to evaluate and rank traffic parameters and geometric elements of urban single-lane roundabouts. The model was built based on comprehensive review of the research literature and existing roundabout simulation software, a field survey of 61 civil and traffic expert engineers in Croatia, and field studies of roundabouts in the Croatian capital city of Zagreb. We started from the basis of Kimber's capacity model, HCM2010 serviceability model, and Maycock and Hall's accident prediction model, which we extended by adding sensitivity analysis and powerful MOO procedures of the bounded objective function method and interactive optimization. Preliminary validation of the model was achieved by identifying the optimal and most robust of three geometric alternatives (V.1-V.3) for an unsignalized single-lane roundabout in Zagreb, Croatia. The geometric parameters in variant V.1 had significantly higher values than in the existing design V.0, while approaches 1 and 3 in variant V.2 were enlarged as much as possible within allowed spatial limits and Croatian guidelines, reflecting their higher traffic demand. Sensitivity analysis indicated that variant V.2 showed the overall highest TE and TS across the entire range of traffic flow demand and pedestrian crossing flow demand at approaches. At the same time, the number of predicted traffic accidents was similar for all three variants, although it was lowest overall for V.2. The similarity in predicted accident frequency for the three variants suggests that V.2 provides the greatest safety within the predefined constraints and parameter ranges explored in our study. These preliminary results suggest that the proposed model can optimize geometry, TE and TS of urban single-lane roundabouts.

The global process of life in urban areas, and the enormous increase of agglomeration, placed today in front of transport planners, and other professionals’ crucial question: how to increase or retain mobility of the urban environment, with sustainable transport system? Parking, as a natural consequence of the use of personal vehicles, is the activity which can successfully manage the overall demand for transport using personal vehicles. Many cities around the world use parking policy as a good mechanism for managing demand for transport. The aim of this paper is to present a model of transportation demand management policy of parking in the City of Zagreb, and on the basis of the analysis, suggest future directions of the overall transport and parking policy in the City of Zagreb.

The traffic system is as essential to modern society as the circulatory system to the human body. Road section design is therefore a key infrastructure activity for economic development, and multi-criteria decision-making can provide an interdisciplinary approach that moves beyond purely economic optimisation to include technological, technical and ecological factors. The present work describes applying the multi-criteria Analytical Hierarchy Process (AHP) method to evaluate road section design in an urban environment through differential weighting of various criteria and sub-criteria. The model is tested on a stretch of National Road D8 in the municipality of Podstrana near the city of Split (Croatia), which serves as an important route for commuters and tourists. The proposed AHP model provided reliable results that were robust to sensitivity analysis. This approach involving differential criterion weighting may prove useful for evaluating and selecting appropriate road section designs for this and other contexts.

Studying cycling traffic issues in a beginner city – City of Zagreb, stems from unclear development policy, an increase in cycling volume, a large number of traffic accidents, an inadequate infrastructure and legislation, a small number of high quality studies and published papers, and the question, did current cycling policy and programs advance cycling? A comprehensive search of available literature, including data from the Zagreb Traffic Department, was made. These data do not adequately address the direction of causality, such as whether current cycling policy and programs advance cycling or whether cycling demand led to increased levels of cycling. This review paper suggests that, it is not yet possible to evaluate which pro-bicycle packages are the most effective and, development of cycling traffic requires a coordinated holistic planning strategy. Results could serve as a beacon light for similarly sized beginner cities, especially those who are located in South-eastern and Eastern Europe.

Level crossings (LCs) are points of conflict between rail and road traffic. Therefore, from the aspect of safety they are potentially high-risk traffic points. Traffic participants at LCs are pedestrians, cyclists, motorcyclists, car drivers and locomotive drivers. The behaviour of traffic participants represents the main cause of traffic accidents at LCs. Most research examining road users’ behaviour at LCs has focused on car drivers and there are few studies dedicated to pedestrians and cyclists, especially in Croatia. Cyclists are often treated like pedestrians but cyclists can travel much faster than pedestrians, which can cause unexpected behaviour. The paper gives an overview of the existing cycling features in the City of Zagreb and the statistics of accidents on LCs in the Republic of Croatia. Also, through a review of the major recent studies on the behaviour of pedestrians and cyclists at railroad crossings, the trends have been presented as well as the results of research. The review paper will serve as the basis for further research of design, traffic safety and the behaviour of pedestrians and cyclists, and their correlation at the LCs in the Republic of Croatia

The global process of life in urban areas, and the enormous increase of agglomeration, placed today in front of transport planners, and other professionals’ crucial question: how to increase or retain mobility of the urban environment, with sustainable transport system? Parking, as a natural consequence of the use of personal vehicles, is the activity which can successfully manage the overall demand for transport using personal vehicles. Many cities around the world use parking policy as a good mechanism for managing demand for transport. The aim of this paper is to present a model of transportation demand management policy of parking in the City of Zagreb, and on the basis of the analysis, suggest future directions of the overall transport and parking policy in the City of Zagreb.

The CiViTAS Initiative is the EU response to the growing problems caused by traffic in European urban centres such as traffic congestion, noise, exhaust gases and difficult access to the city centre. The CiViTAS Initiative helps cities to test and develop an integrated set of measures for sustainable urban mobility. One of the projects is CiViTAS ELAN where five cities Ljubljana, Gent, Zagreb, Brno and Porto are cooperating. The goal of this project is to improve the quality of life for citizens and to implement better solutions in urban transport by promoting and enhancing sustainable, clean and energy efficient ways of transport. It is funded by the FP7 Programme and total duration of the project is 48 months from 2008 to 2012. As a part of CiViTAS ELAN, the City of Zagreb wants to discourage the use of cars by making public transport and cycling as a more attractive alternative. CiViTAS highlights in Zagreb are: decrease of traffic congestion, improvement of quality, accessibility and attractiveness of public transport, switch to cleaner modes of public transport, lower environmental impact of city fleet, inclusion of the existing railway into the city’s public transport system, improvement of cycling conditions and introduction of alternative modes of transport and mobility i.e. car pooling. The paper will present some measures and their results after three years of project implementation such as decreased congestion in pilot corridor along Savska street, decreased energy consumption and noise, improved public transport quality by purchasing 70 energy efficiency trams and 160 buses on gas or bio-diesel, e-ticketing, inter-modal solutions, etc.

Developing cycling traffic helps urban centres to advance sustainable citizen mobility. The reason for researching cycling traffic issues in a beginner city (City of Zagreb) stems from poor safety numbers, an increase in volume, unclear development policy, an inadequate infrastructure and legislation. The question arises, did current cycling policy and programs advance cycling? We analyse the current state of cycling traffic and cycle promotion policy in order to assess the actual impacts of these various interventions on the level of cycling. A comprehensive search of available literature, including data from the City Office, has been made. This review paper suggests that development of cycling traffic requires coordinated programs and a holistic planning strategy which includes all stakeholders. Results could serve as a beacon light for similarly sized beginner cities, especially those who are located in Eastern Europe.