With road safety treatments in urban areas, there is a tendency to identify a problematic site and implement improvements in isolation with little consideration for up and downstream conditions. Often the improvements involve physical enhancements such as improving guidance, traffic control or road geometry which are above and beyond what are actually needed in terms of design warrants. However, the high crash rates are often a result of large volumes of conflicting traffic streams, rather than these physical deficiencies. The implementation of isolated improvements in this manner may not be appropriate in addressing the greater road safety problem. In addition, improvements carried out at one location, may lead to traffic re-distribution effects and crash migration which would merely move the problem elsewhere. In this regard, there is a need to further explore opportunities for addressing urban road safety requirements through optimisation of the network from a traffic management perspective. Isolated improvements will still be required for distinct crash clusters, but these should also be implemented with consideration of the greater network. (a) For the covering entry of this conference, please see ITRD abstract no. E214666.
Samenvatting