#42 Motorcycle Crash Types

Recent research in Australia (de Rome et al., 2024) examined the coding systems used to define motor vehicle crash types and contributing factors in official datasets, aiming to assess the suitability of the system in the context of motorcycle crashes specifically. A key finding of the research was that the current system in Australia, based on Definitions for Classifying Accidents (DCA) and Road User Movement (RUM), defines crash type by the ‘last vehicle movement before the first crash impact’. Importantly, this system does not distinguish between vehicles of different types and therefore overlooks the often unique characteristics of motorcycle crashes.

Based on a sample of 1479 police-reported motorcycle crashes in Tasmania from 2013-2016, the research drew on text narratives in police reports to identify the precipitating events prior to the last vehicle movement. In many cases, a ‘single vehicle’ motorcycle crash may have resulted directly from avoiding another road user (or animal) encroaching on the motorcycle rider’s right-of-way. As such, while the last movement is often associated in the data with a ‘loss of control’, this does not provide sufficient detail or context to inform the development of appropriate countermeasures.

In terms of statistics, analysis of police-reported narratives resulted in the primary recoding of 47% of motorcycle crashes and revised sub-coding of 57% of crashes that ‘remained within the original category’. 102 crashes identified as ‘single vehicle’ were reclassified as multi-vehicle crashes due to significant involvement of (albeit without impacting) another vehicle. These included rear-end incidents, where motorcyclists were the ‘key vehicle’ in most cases (74%), and ‘head-on’ incidents, where around 94% of cases involved the motorcyclist avoiding another (errant) vehicle.

Finally, in the words of the authors de Rome et al. (2024),

The key finding is that using the last vehicle movement before the first crash impact, as the basis for classifying motorcycle crashes, is inappropriate and misleading due to the different crash kinematics of one and two-track vehicles.

de Rome, L., Hurren, C., & Brandon, T. (2024). A Review of the Accuracy of Crash Coding When Applied to Motorcycle Crashes. Journal of Road Safety, 35(4), 42–53. https:/​/​doi.org/​10.33492/​JRS-D-24-4-2460607.