Risk factors at 50 km/h intersections with traffic lights : methodological follow-up and further exploration of the quantification of risk factors such as red light runningrunning. In 2016, SWOV investigated risk factors in traffic. These risk factors are also known as Safety Performance Indicators (SPIs) and are an indication of hazards in road traffic. Policy makers can use these risk factors for the development of proactive, ‘risk-based' policy. Risk factors can be differentiated in behaviour in traffic – such as distraction, fatigue and red light running – and design characteristics of the road traffic system, such as compatibility between the speed limit and the road design. In one of the 2016 studies on risk factors we set out to identify the factors that may play a role in causing crashes at intersections on municipal 50 km/h roads. As a basis the researchers used information on fatal crashes in 2012 from registration sets of the police. They investigated to what extent certain predefined dangerous behaviours had possibly or certainly played a role in causing or increasing the severity of these fatal crashes. Next, one of these risk factors was further quantified: red light running. This was done by investigating whether red light running had occurred in the fatal crashes that were studied and by looking at cases of red light running without crashes occurring by carrying out street measurements. As a follow-up to the 2016 study, SWOV in 2017 also studied the quantification of risk factors, and did this – because of its focus on red light running – specifically at 50 km/h intersections that are regulated with traffic lights. This follow-up study set out to answer the following research questions: What additional or alternative data sources can be used to quantify risk factors and what (initial) insights can be obtained by using these sources ?; How reliable and generalizable are the findings from the previous research (for example, in terms of time, locations, assessors) ?; Which recommendations for further research into risk factors can be formulated on the basis of the findings from the previous two questions ?
Samenvatting