Every barrier has a beginning and an end. It is impossible to have an infinitely long barrier. Safety barrier ends can be deadly to oncoming traffic unless they are treated properly. Most treatments have configured the end of the barrier into a specially designed shape to reduce the violence of impact. One of most popular solutions in 1970s was to turn the end down to form a ramp. Tests have however shown that this can be extremely dangerous, but they continue to be used. CALTRANS in 1978 was one of first agencies to realise dangers of ramped ends, and in 1990 Federal Highway Administration banned their use on new guard rails on high speed, high volume roads in the US. They cited availability of crashworthy end terminals which were more effective than turned-down ends in protecting the ends. In some countries, turned down ends are now also prohibited. Other countries are reluctant to do so because the alternative end treatments cited by FHWA are relatively unknown outside North America. The purpose of this paper is to focus on alternative end treatments and their characteristics, and to emphasise the importance of matching these systems to specific site conditions when selecting the end treatment.
Samenvatting