Safety performance models for pedestrians and bicyclists

Thomas Jonsson

Safety performance models are essential tools for traffic safety work, and are used to estimate the expected number of accidents in an intersection, on a road segment or other entity of the road network. The models are based on accident history for several years and for many intersections/segments, thus trying to counter the large random variation in accident counts between individual years and places. Much research has been done within the area of safety performance models, but the vast majority of it has been done for motorized traffic. With an increased focus on sustainable traffic and increased demand for walking and biking there is also need for good models for these transportation modes, but very limited research has been carried out so far in this area. This paper reports mainly on two recent Swedish studies with a special focus on safety performance for pedestrian and bicyclist. The first Swedish study was based on police reported accidents on 400 urban street segments and the second on both hospital and police reported accidents on 360 segments and 63 intersections. Short counts of pedestrians and bicyclists were carried out to account for exposure in the models. The statistical approach used for the model development was quasi-Poisson in the first study and Negative Binomial in the second one, both approaches accounting for over/underdispersion in the accident count. The developed models exhibit a ‘safety in numbers’, i.e. the risk for an individual pedestrian/bicyclist to be involved in an accident decreases with an increase in the number of pedestrians/bicyclists. This effect is stronger for bicyclists than for pedestrians. The short counts were shown to significantly improve the predictive capability of the models compared to only using proxies for their number, such as street type or type of built environment along the street.



Millions for research into maritime transport and the environment

Maritime transport is a major source of emissions of harmful air pollutants and carbon dioxide. In a new project, a research team from the Swedish National Road and Transport Research Institute (VTI) and the University of Gothenburg has received SEK 6.4...


New research programme for more efficient travel

The Swedish National Road and Transport Research Institute (VTI) is playing an important role in a major new research programme to find radical solutions leading to fewer trips and more efficient travel, along with tools to enable better use of roads and...


Simulator used to practice emergency responses safely

Emergency responses of the police, ambulance, and rescue services are associated with a high risk of accidents, but practicing them in real traffic is neither safe nor permissible. A simulator-based method developed by the Swedish National Road and Transport...


Simulation of cut-in by manually driven vehicles in platooning scenarios

A study in a VTI-driving simulator has showed that a platoon will be able to handle a cut in from a manually driven car. The results of this study have recently been presented at two conferences in Japan.



The five-year anniversary of European Road Profile Users' Group (ERPUG) Forum will take place at Ramboll head quarter, Copenhagen, Denmark October 19-20, 2017.


Self-driving buses in Sweden next year?

A self-driving, fossil-free bus. This idea might become reality through a forthcoming collaborative project involving the Swedish National Road and Transport Research Institute (VTI), Linköping University and several other participants. The project group aim...