Roadside safety audits

Roadside adjustment has a remarkable effect on road safety. An effective strategy for roadside safety improvement may be based on safety audits, both of detailed design and of existing roads. Accident data analyses do not always allow to locate the roadside safety problems because usually roadside defects have limited extension and may not have influenced in meaningful way the accident rates. However, a roadside punctual analysis aimed at identifying the accident potential and safety performance may be an effective approach with low costs and great benefits. A roadside safety audit of some Italian highways has underlined a lot of safety problems which, in most cases, are of repetitive nature and may be eliminated or mitigated with low cost measures. Main roadside safety problems have been classified and detailed checklists have been developed. The main dangerous factors singled out relate to the safety barriers structural adequacy (low containment capacity in sites with high dangers, behavior excessively rigid towards the passenger cars), to the safety barriers functional adequacy (inadequate longitudinal extension for the complete protection of the obstacles, inadequate distance from the protected obstacles, installation conditions not suitable, etc.), to the safety barriers transitions and terminals, other than to the presence of unprotected obstacles inside the clear zone.