In this paper, the design and development of an energy absorbing front underrun protection system with composite crash cones is described and the performance is demonstrated in a 70kph full-scale car-to-truck frontal collision. The results are compared with the results of a test with identical vehicles, where the speed was 57kph and the truck was fitted with a rigid front underrun protection device. Crash cones of composite material can successfully be used as energy absorbers in a structure used as an energy-absorbing truck front underrun protection system. It is demonstrated that the use of an energy-absorbing truck underrun protection system can result in significant improvements in occupant survivability. With a good design, even higher impact velocities than 75kph may be feasible for modern cars using modern technology.