PERTA – Passive Sicherheit in der Straßenausstattung

In the event of a collision against a stationary obstacle, deep intrusions into the vehicle interior can be expected which lead to severe injuries. Investigations of the impact configurations have shown that frontal collisions with stationary obstacles on the side of the road, such as traffic signs, posts or lighting poles, account for approximately 80% of all possible impact configurations.
The aim of the study was to examine the passive safety of traffic signs ('Gabelständer' and 'Trimast'). Based on the results recommendations should be developed if these traffic signs need to be shielded by road restraint systems.
As method a mix of real tests and finite element simulations was chosen. Two tests for each traffic sign served as a basis for the validation of the simulation models. Based on the validated simulation models, the traffic signs were modified and in the simulations the passenger safety was evaluated according to the criteria of EN 12767. Essential criteria were the index for the severity of acceleration (ASI: Acceleration Severity Index) and the theoretical impact velocity of the head (THIV: Theoretical Head Impact Velocity).
The main factor in achieving passive safety of traffic signs was found to be the tearing off of the belt tubes at the impact. If the belt tubes tear off, the values for ASI and THIV are below the limits according to EN 12767. Main factors were identified as belt tube diameter and the design of the foot plates. Fixed footplates support the tearing off of the belt tubes and the values for the ASI and especially the THIV are below the limits.
The belt tube height, the distance between the belt tubes and the shield itself only have a minor influence. Different diagonal tube layout, weakening of the belt tubes or reduction of the weld circumference positively influence ASI and THIV.