This paper presents a study aimed at quantifying and comparing the risk of personal injuries associated with road barrier collisions. Documented data from actual barrier collisions, including post-impact collisions, in Sweden between 2005 and 2008 were analyzed. The analyses were based on the injury classification made by healthcare services. The injury rates, measured in number of injuries per vehicle kilometer travelled, were calculated for the different injury classes as a basis for evaluating barrier performance. The results show that the rate of injuries was higher due to collisions with flexible barrier systems, such as cable barrier, than with other semi-rigid and rigid barrier system, such as w-beam and concrete barriers. This result might be explained by a high rate of post-impact events, such as post-impact collisions, roll-overs and over-rides, associated with the placement and mechanical properties of the cable barriers. The study also showed a considerable difference in injury classifications made by the police and the healthcare services, as well as a considerable under-reporting of barrier collisions by the police.