In future, new trucks shall most likely be equipped with a front under-run protection devices in order to prevent passenger cars from under-running. At the same time, the energy absorption by the car will be more adequate, because of the better geometrical compatibility with the truck front. As yet, this device shall not be designed with the objective to absorp energy in favour of the passenger car. From European accident analysis it is known that the average relative speed in a car-to-truck frontal collision is about 76 kph. Today, passenger cars are designed to provide protection to the occupants up to 56 kph in a frontal collision with a rigid wall. If a part of the impact energy could be absorbed by the truck, the injury severity to car occupants in a 75 kph collision would be reduced to survivable injuries observed in a 56 kph collision into a rigid wall. In order not to influence the payload of the truck, the energy absorbing front under-run protection system should be light and compact. Moreover, such a system should be cheap and easy to integrate into future truck design. Materials which could be considered are composites. It is known that composite crash cones have a very high specific energy absorption and are therefore exquisite for application in this field. In this paper, the design and development of an energy absorbing front under-run protection system with composite crash cones will be described and the performance will be demonstrated in a full-scale car-to-truck frontal collision. The results will be compared with the results of a test with identical vehicles, where the speed was 56 kph and the truck was provided with a rigid front under-run protection device.