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 recent SWOV research (Stipdonk et al., 2016).
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.
The question is, however, which design variant is safest and whether the current preference is therefore still in line with the knowledge we have now.
The Rijkswaterstaat department Water, Traffic and Environment (WVL) asked SWOV to find an answer to that question by means of a literature study. WVL also asked for a survey of the advantages and disadvantages (in terms of costs and benefits) of the various design options.
