Crashworthiness ratings measure the relative safety of vehicles in preventing death or serious injury to their drivers in crashes. This study has successfully estimated trends in the crashworthiness of the light passenger vehicle fleet in New Zealand by both year of manufacture and year of first registration in New Zealand. Years of vehicle manufacture from 1964 to 2002 have been considered through analysis of data on police reported crashes involving injury in New Zealand over the period 1991 to 2002. Estimates have been obtained for the fleet as a whole as well as broken down by vehicles sold new in New Zealand and vehicles imported second-hand.
There was statistically significant improvement of 50% in the crashworthiness of New Zealand light passenger vehicles over the study period. The majority of the measured improvement occurred from 1983 to 2002, a period in which New Zealand vehicle safety was affected by several competing factors including engineering improvement, increasing used vehicle imports and increased Government regulation. Level of absolute crashworthiness and trends on a year of manufacture basis were similar for used imports to those for vehicles sold new in New Zealand. Estimated crashworthiness trends of used import vehicles by year of first registration in New Zealand showed statistically significant improvements from 1978 to 1998. Absolute levels of crashworthiness and improvements by year of first registration paralleled those seen in the analysis by year of manufacture but occurred some 6 years later, a lag equivalent to the average age of the used imported vehicles over the study period. Implications of the used import program on overall vehicle safety in New Zealand are discussed.