Every third road accident in Poland involves a pedestrian as a participant or, most of the time, a casualty. Pedestrian accidents are usually the result of complex situations and the outcome of a number of factors related to driver and pedestrian behaviour and road infrastructure. Safety depends largely on how well the traffic condition is perceived and on visibility in traffic. The re-lations between pedestrians and motorists and the resulting hazards should researched to ensure that pedestrians are provided with the right conditions for walking.
Low-temperature cracking is one of the most common road pavement distress types in Poland. While bitumen performance can be evaluated in detail using bending beam rheometer (BBR) or dynamic shear rheometer (DSR) tests, none of the normalized test methods gives a comprehensive representation of low-temperature performance of the asphalt mixtures. This article presents the Bending Beam Creep test performed at temperatures from −20 °C to +10 °C in order to evaluate the low-temperature performance of asphalt mixtures. Both validation of the method and its utilization for the assessment of eight types of wearing courses commonly used in Poland were described. The performed test indicated that the source of bitumen and its production process (and not necessarily only bitumen penetration) had a significant impact on the low-temperature performance of the asphalt mixtures, comparable to the impact of binder modification (neat, polymer-modified, highly modified) and the aggregate skeleton used in the mixture (Stone Mastic Asphalt (SMA) vs. Asphalt Concrete (AC)). Obtained Bending Beam Creep test results were compared with the BBR bitumen test. Regression analysis confirmed that performing solely bitumen tests is insufficient for comprehensive low-temperature performance analysis.
The paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasicontinuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate and the air voids composing the material. The model directly captures random nature of material parameters and aggregate distribution in specimens. Initial results of the analysis are presented here.
Preferences and Transport Behavior of Gdansk Residents in the Light of the Result of Complex Traffic Survey
Preferences and transport behavior of the population are a fundamental aspect of research in public transport. Identifying the basic postulates of transport, the factors determining the specific behavior of transport and modal split allow to analyze the differences between the groups singled passengers and to prepare better offer of an urban transport. In Poland, still in many cities urban transport research is conducted ad hoc, in a situation when you need to carry out specific investment projects. Meanwhile, transportation demand and preferences and behavior of the inhabitants should be carried out regularly every 2 years, not less than 5 years. In Gdansk, transportation preferences and travel behavior of residents of Gdansk is carried out every 5 years as part of the Complex Traffic Survey (CTS). The objective of this article is to present and compare the results of CTS conducted in 2009 and 2016. The basic of the analysis is the thesis that the preferences and transport behavior of Gdansk residents have changed.
When planning their transport policy, cities usually focus on developing sustainable transport systems and reducing the negative consequences of transport. One way to deliver transport policies is to use the Sustainable Urban Mobility Plan (SUMP), a strategic document designed to meet the demand for mobility whilst ensuring adequate quality of life for the residents. The process of Sustainable Urban Mobility Planning (SUMP process) can be supported by using a transport model. The objective of this article is to analyse the efficacy of the Multilevel Model of Transport Systems—referred to by its acronym, MST—for the SUMP process. With its ability to represent the transport system’s behaviour depending on the level of detail, the MST can significantly benefit the SUMP process. The proposed concept of integration of the MST into the SUMP process has already been tested and applied in delivering Gdynia’s (Poland) SUMP. The paper suggests ways to use the MST at different levels of planning and modelling and describes the outcomes. Using the multilevel structure helps to fully realise the transport model’s potential to improve the effectiveness of urban mobility planning. The conclusions show that the methods proposed in the article are worthwhile and cities should consider them when planning the SUMP process.