The subject of this study is about the influence of network structure and road classification on road safety. Road safety, or unsafety, is usually expressed as the number of crashes or casualties. It is not evident how one can relate what happens at street level to the decisions regarding network design and the elaboration of this design. Traffic circulation can be regarded as the link between these two levels. Behind traffic circulation is the individual who decides to travel from a point of origin to a destination, using a particular route. The route is the starting point for this study. That is because network structure and road classification are important preconditions for traffic circulation and route choice, while the intersecting routes will determine the crash locations. This study will therefore focus on the effects of changing route choices on road safety. The changes in route choice may be the result of: 1. (intended) changes in the structure of the road network; 2. a change in traffic circulation, e.g. on account of an alteration of a traffic signal system or of congestion on the main roads; 3. instructions to car drivers through navigation systems or route guidance signs. These changes, adaptations and instructions aim to improve the traffic and transport system as a whole. This study is undertaken to find the effect of the changes/instructions enumerated above on the safety of all road users in the road network. This study will show whether an improvement can be attained and how it can be attained. In this study, an attempt was made to connect different worlds; the world of transport network design, the world of route choice research, the world of micro-simulation modelling, and finally, the world of surrogate safety measures (conflict indicators). (Author/publisher)
Samenvatting