Development of surrogate measures for crash-based safety estimation

Bhagwant Persaud
Taha Saleem
Yongsheng Chen

The paper investigates the validity of promising surrogate measures by investigating the link between such measures and safety. Such measures, if shown to be valid, can be used in two ways: a) to evaluate a newly implemented measure for which data can be quickly assembled to estimate the effect on the safety surrogate and, by implication, the effect on expected crashes, and b) to estimate the safety effects of a proposed change by first estimating the effect on the safety surrogate and then relating that outcome to the expected change in crashes. The idea is not new. In fact, several researchers have been working on various complementary pieces of the puzzle. The key missing link is in developing measures that can in fact be linked explicitly to safety as manifested in expected numbers of crashes. In addressing this void, two complementary sets of models are explored – models to relate surrogate measures to design features and models to relate crashes to surrogate measures. The first set successfully modeled simulated conflicts for urban signalized intersections estimated from micro-simulation software, complementing the models for measured and predicted speeds for roundabouts that have been developed in our recently published research. Models relating these surrogate measures to observed crashes suggest that there is promise in the approach of using certain surrogate measures for crash-based safety estimation.



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...