Comparison of Collisions of Rigid Trucks and Articulated Trucks Against Road Safety Barriers

Heavy vehicles used for road transport are essentially rigid trucks, rigid trucks with trailers, and articulated trucks. A collision of such a vehicle against a safety barrier has different outcomes, depending on the vehicle characteristics, even when the impact energy (Ie) is the same. The factors responsible for the different behavior of rigid and articulated trucks during collision are addressed. The study, carried out by computer simulation, was divided into three parts. The first part compared the overall behavior of the two types of vehicles during collisions to detect the most responsible factors. In the second phase, the single features that characterize each type of vehicle were tested. The third phase tried to define a relationship between the two types of vehicles. Results from Tests TB81 and TB71, established by the European Committee for Standardization 1317, were compared. The results show that a collision of an articulated truck is less severe than one of a rigid truck because of greater length, suspension stiffness, inertia, and configuration. However, the difference in behavior depends on kinetic Ie and side-friction coefficient (SFC). Four analytical expressions were found that relate Ies producing the same maximum transversal displacements or vehicle roll angle for the two types of vehicles. The study concerning the European tests on safety barriers shows that a hierarchy exists between them and it depends on the SFC.