Interaction between Powered Two-Wheeler Accidents and Infrastructure

Traffic safety as a challenge to reduce accidents, injuries and fatalities is still an important social problem in spite of the wide introduction of sophisticated safety measures to the road user, the vehicle and the infrastructure. One of many factors that are likely to contribute to an increase in road transport safety risks includes the increasing number of vulnerable road users, such as motorcyclists. The aim of the reported work within the 2-BE-SAFE project, WP1, was to highlight the potential influence of the road infrastructure characteristics on the motorcycle accident risk. As a usual starting point of many research works, a literature review to specify the actual State of the Art, took place. The results have shown that a lot of questions are not completely answered - especially the influence of specific road condition parameters together with alignment types and road geometry on powered two-wheelers (PTW) accident types. A comparison of country specific analyses has not been found. Most of the results who define the State of the Art are very general, but gave fruitful hints for the design of the studies conducted and reported on the following pages. The first step of investigation was the macroscopic analysis of each single partner (country). Results from each participant country (Greece, Spain, Italy, Great Britain) on risk factors regarding the junction types, the road area types, the most critical accident types share many common points and are often comparable. Other potential risk factors show trends, which differ in each country - like the basic accident data itself. This unique comparison of possible infrastructure risk assessment also reflects also an obviously differing rider´s philosophy (different motives to ride a motorcycle - urban/interurban rate of mileage, motorcycling for fun and to substitute the passenger car). In the final stage of the project, a more in-depth view on the PTW accident event and the road section, where cashes occurred, has been accomplished. Microscopic analyses on specific physical values of road condition characteristics as well as detailed information on the trace parameters were correlated with PTW accidents. Parameters measured by special devices and/or in-depth accident data of the accidents are used to fulfil the aim finding risk factors regarding the road infrastructure. Unique data correlations show trends of potentially risky crash circumstances regarding the surface characteristic and e.g. curve radii classes. In-depth analyses reveal the negative effects of impacting a road restraint system. Participating countries are Spain, Germany and Austria. Even similarities in risk factors and obvious trends of critical road infrastructure are explored in that European survey; it also proves that the issue of motorcycle is much more complex than often thought. European wide solutions to decrease PTW accidents by making the road infrastructure "motorcycle friendly", self-explaining and forgiving needs an in-depth understanding of the vehicle-road-interaction and its dynamics. A strong connection of road types, the mileage per year and the purposes of the rides are also feasible, in order to understand the motives of motorcyclists using a specific route. Especially the microscopic analyses of specific road sections has shown a strong need for further research regarding the interaction between motorcycle tyres and road surface condition. Characteristics of PTW accidents spots are in some points comparable within the European context, but other black spots specifications are even in one country unique - statistically insignificant, but highly dangerous. With that kind of studies within that task a unique comparison of risk factors depending on road infrastructure factors could be shown.