Occupant and exterior safety of low mass cars (LMC)

Walz, Felix H.; Kaeser, Robert; Niederer, Peter

Affiliations

¹Institute of Forensic Medicine, University of Zurich, Zurichbergstr. 8, CH-8028 Zurich

²Institute for Lightweight Structures, Swiss Federal Institute of Technology, Leonhardstr. 25, CH-8092 Zurich

³Institute of Biomedical Engineering, Swiss Federal Institute of Technology and University of Zurich, Moussonstr. 18, CH-8044 Zurich

Abstract

The increasing public demand for vehicles characterized by a low energy consumption combined with a favourable emission profile is currently leading to the development of low mass cars (LMC). Typical masses are anticipated to be around 500 kg for a vehicle capable of accommodating two occupants and an acceptable baggage load. The fuel consumption should not exeed two litres per 100 km (or electric equivalent). These cars will however circulate in general traffic together with many much heavier vehicles. Due to cost and weight restraints as well as due to the involvement of manufacturers lacking in-depth experience in mass production of cars and in safety engineering, conventional low mass vehicles must be expected to be associated with a severe occupant safety problem.

Conventional car crashworthiness features include an exterior deformation zone of maximal possible size in combination with a rigid passenger compartment allowing for a favourable occupant ride-down in the case of a frontal collision. Side collisions are given increasingly more attention while offset and oblique impacts remain problematic. Already a crude analysis shows that a comprehensive safety concept has to be worked out for LMC’s which can only partially be adopted from conventional design. A stiff exterior which is largely identical with the passenger compartment, an increased size of this compartment as a partial compensation, a possible removal of the steering column, the steering wheel and the foot pedals allowing the integration of safety seats into the vehicle structure, combined with a customized airbag, an advanced belt system and an injury reducing interior contact zone highlight the topics of the future development of LMC’s. Since low mass vehicles are expected to be used predominantly in urbanized areas with a high percentage of unprotected road users, furthermore, special attention will have to be given also to the exterior collision safety.

A comprehensive safety improvement for LMC’s includes also a number of measures in the area of accident prevention and collision avoidance.

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Cited By (5)

Year	Entry
1998	Mizuno K, Kajzer J. The compatibility of mini cars in traffic accidents. In: Proceedings of the 16th International Technical Conference on the Enhanced Safety of Vehicles (ESV). May 31–June 4, 1998; Windsor, Ontario, Canada.715-728.
2009	Pipkorn B, Kullgren A. Effects of active structures on injuries in medium severity frontal impacts. In: Proceedings of the 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 15-18, 2009; Stuttgart, Germany.
1992	Kaeser R, Walz FH, Brunner A. Collision safety of a hard shell low mass vehicle. In: Proceedings of the 1992 International IRCOBI Conference on the Biomechanics of Impact. September 9-11, 1992; Verona, Italy.133-142.
1993	Niederer PF, Kaeser R, Walz FH, Brunner A, Faerber E. Compatibility considerations for low-mass rigid-belt vehicles. In: Proceedings of the 1993 International IRCOBI Conference on the Biomechanics of Impact. September 8-10, 1993; Eindhoven, The Netherlands.433-444.
2007	Pipkorn B, Mellander H, Andersson T, Olsson J. Means of crash pulse variation and the injury reducing potentials in moderate and high severity frontal impacts. In: Proceedings of the 2007 International IRCOBI Conference on the Biomechanics of Impact. September 19-21, 2007; Maastricht, The Netherlands.301-310.