On most French highways, hard shoulders are equipped with safety barriers to protect vehicles from running off the roadway. The research question is to determine if there would be a global safety gain to the user in systematically equipping all hard shoulders with safety barriers. The severity of run-off the road is measured and compared according to if they occur with a protected hard shoulder or a non-protected one, and in the latter case, whether what is off the road is at the same level, an embankment or a ditch. The data relates to five years of observation - 1996 to 2000. Results of the research indicate that the severity of run-off the road on hard shoulders is on average significantly higher in the absence of a safety barrier. Higher values of severity are connected with run-off the road in the presence of embankments or ditches. These results take into account the typology of the accident (number of vehicles involved, different impacts, type of vehicle involved) and of highway characteristics. Severity differences are large enough to be significant. It is concluded that systematic equipment of highway hard shoulders appears to be beneficial as a whole within the infrastructure and European traffic conditions, with a better control of run-off the road consequences.