Methods for Measuring Motorcycle Speeds and Their Implications for Understanding ‘Safe Speeds’

Abstract

New Zealand traffic accident data show that motorcycles account for 13% of road crash fatalities but that motorcyclists undertake only around 0.5% of travel time or trips. From these statistics, it is determined that motorcyclists are around 16-23 times more likely to be involved in a fatal or injury crash than car drivers. The high relative crash risk for motorcycles is replicated in every country; only the magnitude of the estimate varies, as motorcycles are always the most dangerous form of travel. One report estimates that motorcycles have a relative crash risk as high as 34 times that of cars. Based on vehicle registrations, the number of motorcycles may seem insignificant: they constitute only 3.47% of the NZ vehicle fleet. However, motorcycle registrations have grown to over 100,000 in recent years, with the largest increase occurring between 2004 and 2008. The popularity of the motorcycle comes and goes but the recent rise in registrations coincides with increased rates of crashes resulting in death or injury. Stephan et al reviewed fatal motorcycle accident files from 115 Australian coroners’ cases and found the rider was travelling too fast for the conditions in over 70% of cases. This conclusion is made notwithstanding that forensic techniques used for estimating a motorcycle’s speed from crash scene evidence are far less accurate than those available for cars.