The New Car Assessment Program (NCAP) : has it led to stiffer light trucks and vans over the years ?

Since model year (MY) 1983, 175 light trucks, vans, and sport utility vehicles (LTVs) have been included in the New Car Assessment Program (NCAP) frontal crash tests. In this paper, the acceleration data from accelerometers in the occupant compartment and from dummies are analyzed to determine: (1) the trend of total stiffness or aggressivity characteristics of LTVs since MY 1983; (2) the trend of the approximate linear, stiffness of LTVs during the first 200 mm of crush since MY 1983; and (3) the effect of these structural characteristics on the NCAP safety ratings. The effect of aggressivity and stiffness parameters on the dummy responses is examined. It is shown that, on the average: (i) the maximum dynamic crush and the time period of the acceleration pulse have increased over time. The maximum acceleration of the vehicle structure has decreased over time; (ii) the approximate linear stiffness in the first 200 mm of crush has decreased over time; and (iii) that there is a correlation between lower stiffness and aggressivity parameters and better NCAP scores. These findings indicate that NCAP may have influenced manufacturers to design less aggressive, and, therefore, more compatible LTV front structures for both front to front and front to side impacts.