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Abstract: Various systems for rating secondary safety of particular makes and models of vehicles have been developed internationally. These measures generally evaluate crashworthiness (the ability of the vehicle to protect its own occupants in the event of a crash) separately from aggressivity (the harm a vehicle is liable to impose on other road users into which it crashes). This paper describes an approach using Australian and New Zealand data that combines these two facets of secondary safety into one ‘Total Secondary Safety Index’ estimated from real world crash outcomes. The Index estimates the risk of death or serious injury to all key road users in crashes involving light passenger vehicles across the full range of crash types. This paper describes the rationale and method for producing this Index, together with some estimates for common Australian and New Zealand makes and models of light passenger vehicles. [Copyright &y& Elsevier]

Abstract: This paper reports on the findings of a retrospective case series study of fatal motorcyclist–roadside barrier collisions. Cases were retrieved from the National Coroners Information System (NCIS), the coronial case files of Australian jurisdictions, and the Crash Analysis System (CAS) of the New Zealand Transport Agency. Seventy seven (77) motorcycle fatalities involving a roadside barrier in Australia and New Zealand were examined. The fatalities usually involved a single vehicle crash and young men. The roadside barriers predominantly involved were steel W-beams, typically on a bend in the horizontal alignment of the road. A majority of fatalities occurred on a weekend, during daylight hours, on clear days with dry road surface conditions indicating predominantly recreational riding. Speeding and driving with a blood alcohol level higher than the legal limit contributed to a significant number of these fatalities. [Copyright &y& Elsevier]

Abstract: Falls and their injury outcomes have count distributions that are highly skewed toward the right with clumping at zero, posing analytical challenges. Different modelling approaches have been used in the published literature to describe falls count distributions, often without consideration of the underlying statistical and modelling assumptions. This paper compares the use of modified Poisson and negative binomial (NB) models as alternatives to Poisson (P) regression, for the analysis of fall outcome counts. Four different count-based regression models (P, NB, zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB)) were each individually fitted to four separate fall count datasets from Australia, New Zealand and United States. The finite mixtures of P and NB regression models were also compared to the standard NB model. Both analytical (F, Vuong and bootstrap tests) and graphical approaches were used to select and compare models. Simulation studies assessed the size and power of each model fit. This study confirms that falls count distributions are over-dispersed, but not dispersed due to excess zero counts or heterogeneous population. Accordingly, the P model generally provided the poorest fit to all datasets. The fit improved significantly with NB and both zero-inflated models. The fit was also improved with the NB model, compared to finite mixtures of both P and NB regression models. Although there was little difference in fit between NB and ZINB models, in the interests of parsimony it is recommended that future studies involving modelling of falls count data routinely use the NB models in preference to the P or ZINB or finite mixture distribution. The fact that these conclusions apply across four separate datasets from four different samples of older people participating in studies of different methodology, adds strength to this general guiding principle. [Copyright &y& Elsevier]