Purpose: Over the past 10 years, building on road infrastructure data, crash prediction models (CPMs) have become fundamental scientific tools for road safety management. However, there is a gap between state-of-the-art and state-of-the-practice, with the practical application lagging behind scientific progress. This motivated a review of international experience with CPMs from perspectives of application by practitioners and development by researchers. The objective of the paper is to improve practitioner understanding of modelling road safety performance using CPMs for crash frequency estimation, leading to their greater uptake in improving road safety. In short, why and how should road safety practitioners consider CPMs? Methods: Both scientific and practice-oriented literature was retrieved, using academic sources, as well as reports of road agencies or institutes. The selection was limited to English language. Results: From the review it is clear that developing CPMs is not a straightforward task: there are many available choices and decisions to be made during the process without definite guidance. This explains the diversity of approaches, techniques, and model types. The paper explains how some fundamental modelling decisions affect practical aspects of modelling safety performance. Conclusions: There is a need to identify CPM solutions that will be scientifically sound and feasible in practitioners' context. Together with increased communication between researchers and practitioners, these solutions will help overcome the identified challenges and increase use of CPMs.
The design of pedestrian crossings is a complex problem that must consider various factors. The basic criterion for determining the choice of a particular type of pedestrian crossing is traffic safety. To improve traffic safety, typical zebra crossings are being reconstructed, usually with implementation of refuge median islands or traffic signals. However, traffic engineers cannot properly take into account the influence of a type of pedestrian crossing on capacity and traffic progression as negative consequences for both pedestrians and vehicles. A study was conducted on the influence of various types of midblock pedestrian crossings on road capacity. Zebra crossings, crossings with refuge median islands, and signalized crosswalks were analyzed. For the evaluation, a simulation model was built in VISSIM and calibrated with research results on driver and pedestrian behavior. Empirical research confirmed the strong influence of regulations and pedestrian crossing types on the behavior of drivers. The results show that willingness to give right of way on urban streets influences capacity reduction and delays. Taking as a basic criterion overall delay for both vehicles and pedestrians, volume limits for implementation of a pedestrian crossing with a median island or traffic signals are proposed.
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