There is hardly any subject that is researched more than the relation between road safety and speed. This is because we all know that higher speed implies a longer distance to come to a stop if anything goes wrong, and heavier collisions between road users with more energy to be dissipated and stronger forces to be dealt with. Speed can be measured, collisions can be counted, hence it has been a fruitful field of investigation and mathematical model fitting for many decades. One would expect that the relation between risk (e.g.. the number of road deaths per distance travelled, so as to correct for differences in travel) and speed would be established and well known by now. Unfortunately, this is not true. There are almost as many results as there are researchers. For many policy makers, this forest of publications and reports doesn’t exactly make it easy to decide which publication to take as a guide. This paper is meant to shed a light on the most important scientific publications, and help policy makers find their way in the context of management of speed on roads for which they are responsible. It starts with a small choice of some of the issues that have led to confusion, and then proceeds with a description of some of the more established results, their differences and properties. Finally a guide is presented meant to help decide which compass to sail on. (Author/publisher)
Abstract