The Benefits of Double Pretension in Decreasing Knees & Lower Legs Injuries in Frontal Impacts

European official data from the European Road Safety Observatory (ERSO, www.erso.com) shows that Road traffic accidents in 2004 in the Member States of the European Union lead to about 47.000 fatalities and more than 1.8 million people injured. Coming back to the data in France provided by ONISR (Observatoire National Interministeriel de la Securite Routiere) in 2004, 5232 fatalities and 17435 seriously injured people have been observed. 3186 persons died in passenger cars. Frontal impacts represent 47% of killed and 69% of seriously injured people in passenger cars. The distribution is 1290 fatalities in front seats and 143 fatalities in rear seats. Recent progress in passive safety, coming from both regulation enforcement and consumers ratings allowed to solve most of the lethal issues in frontal impact which were: (1) Intrusion (steering wheel, firewall, footwell,…), which decreased with well-designed absorbing structure; (2) Head contact with steering wheel, avoided with frontal airbags; and (3) Chest injuries, reduced with seat belt load limiters. The aim of this paper is to review the evolution of lower legs injuries throughout the last vehicles generations to find out the benefits of advanced restraints systems such like double pretension. The first part of this paper is dedicated to an explanation of the Renault double pretension system, adopted on most of the line-up. Test data using Renault’s current procedure will show the effectiveness of that technical solution compared to a single pretension restraint system. The effectiveness will be shown not only for current 50th percentile occupant usually used in regulation and ratings, but also 5th and 95th percentile occupants. The second part is a review of real accident data provided by the LAB. Injury data have been collected on vehicles fitted with a double pretension and compared with those of the rest of the fleet, in order to estimate the effectiveness of double pretension.