There is no clear evidence for the road safety effect of winter tyres. It is claimed that winter tyres are safer than summer tyres at temperatures below 7 degrees Celsius: winter tyres would provide better grip and shorter braking distances. However, there are hardly any crash studies to support this supposed effect. Moreover, the crash studies that do exist were carried out in countries with very different winter conditions than the Netherlands, such as Sweden   .
More information about winter tyres and their possible road safety effect can be found in SWOV fact sheet Safe passenger cars.