Sustainable Safety version 3 : current situation, societal trends and ideals : framework for the second advanced Sustainable Safety vision for the period 2018-2030. A safe design of roadsides along motorways can help to prevent serious injury in – especially single vehicle – road crashes. Improving the safety of roadsides is also an important measure to reduce the number of people killed on national roads, according to SWOV research. Broadly, there are two basic options for a safe roadside design. The first is the construction of a sufficiently spacious clear zone, so that vehicles running off the road do not hit any objects. Obstacles that cannot be removed, must as much as possible be made 'crashworthy' or be shielded. The second option is to place safety barriers (usually guardrails) along the road. This must, for example, prevent vehicles running off the road colliding with an obstacle. Both variants need a sufficient loadbearing verge as fundamental requirement for a safe roadside design. After all, a sufficient loadbearing verge offers sufficient resistance for braking and changing direction without the wheels sinking into the verge, whereby the vehicle may turn over. A roadside that is designed in such a way that the risk of a run-off-road crash having serious consequences is minimized is called a 'forgiving' roadside. The literature review found no clear answer to the question what is safer: a clear roadside layout or placing guard rails. The reason for this is that a good comparison of the clear zone and the use of barriers is absent in literature. It is clear that both measures have a positive effect on the prevention of serious run-off-road crashes along motorways. There are, however, indications that the positive effects of the current clear roadside design have until now been overrated. The study also indicates that neither guardrail nor clear zone do entirely eliminate the risk of a serious crash. Furthermore, a flexible barrier was found to be significantly safer than a rigid construction. Therefore the conclusion is that a forgiving roadside can be constructed with a clear zone as well as with a flexible barrier. Further, more in-depth research is required to determine the most cost-effective option for various situations.
Samenvatting