The efficiency of current frontal restraint systems in heavy trucks is not comparable to systems in passenger cars. There are no rating tests and legal requirements for the functionality of such systems. Therefore it is comprehensible that even non severe truck crashes in the field lead to non fatal but severe injuries with high rehabilitation costs. Another reason for the low efficiency of the current systems is the non-availability of an adequate development method.

During the development phase of a restraint system it is not possible to observe significant loads applied to the lower extremities by using the conventional test methods. However, the lower extremities gain more and more importance with respect to real world crash data. For that reason a new and approved test method will be introduced and published for the first time. It takes the intrusion of the cabin and interior displacement into account resulting in a good correlation between full scale tests and sled tests.

The new method allows the verification of advanced and additional restraint system components such as optimized knee impact zones, knee airbags and activated steering column kinematics. A restraint system as described above provides optimized occupant kinematics with the effect of reduced loads.

The developed methodology is based on the so called “Trailer Back Barrier” test configuration. However, to date this configuration is not yet being used as a standard evaluation in the industry. This study is concentrating on cab over trucks due to the higher injury risk for the lower extremities compared to bonnet trucks.