This study describes the calculation of updated ratings that measure the relative safety of vehicles in preventing severe injury to people involved in crashes. Three different aspects of secondary safety are examined: crashworthiness which focuses on drivers of the rated vehicle, aggressivity which focuses on drivers of other vehicles and unprotected road users such as pedestrians, cyclists and motorcyclists colliding with the rated vehicle and total secondary safety which examines the combined crashworthiness and aggressivity performance of the rated vehicle.

Updated ratings for 1982-2012 model vehicles were estimated based on data on crashes in Victoria and New South Wales during 1987-2012, in Queensland, Western Australia and New Zealand during 1991-2012 and in South Australia during 1995-2012. Each rating is measured as a combination of injury severity (the risk of death or serious injury given an injury was sustained) and injury risk (the risk of injury given crash involvement). The ratings were adjusted for the sex and age of the person whose injury outcome was being measured, speed limit at the crash location, number of vehicles, crash configuration and type or road user involved where relevant, the jurisdiction in which the crash occurred and the year in which the crash occurred. These factors were strongly related to the risk of an injury being sustained in the crash and the likelihood of injuries sustained being severe. Each rating estimates the risk of being killed or admitted to hospital when involved in a crash, to a degree of accuracy represented by the confidence limits of the rating in each case. Crashworthiness estimates and their associated confidence limits were obtained for 562 vehicle models classified into 10 market groups. Aggressivity rating estimates and their associated confidence limits were obtained for 500 vehicle models.

The total secondary safety index estimates and their associated confidence limits were obtained for 617 vehicle models classified into 10 market groups. A method for presenting the ratings for consumer information is also described. The rating presentation classifies vehicles according to where their rating lies in relation to a best performance benchmark. The relationship between vehicle crashworthiness and the year of manufacture of Australian passenger and light commercial vehicles manufactured from 1964 to 2012 was also investigated. Trends were examined by year of manufacture both for the fleet as a whole and by market group for vehicles manufactured from 1982 to 2012. The results of this report are based on a number of assumptions and warrant a number of qualifications that should be noted.