ABSTRACT
Powered two-wheelers (PTWs) are a vulnerable class of road users with increased accident frequency and severity (Vlahogianni et al., 2012). In the early 1990s, motorcycle death-rate-per-mile-travelled was estimated to be 22 times the death rate for passenger cars (Preusser et al., 1995). In 2007, US motorcycle riders had a 34-fold higher risk of death in a crash than people driving other types of motor vehicles (NHTSA, 2007). In 2008, European motorcyclists represented 17 per cent of road fatalities while only accounting for 2 per cent of road users (IRTAD, 2009). In Greece this figure is as high as 33 per cent (IRTAD, 2013) while in Singapore it reaches 49 per cent with more than two motorcyclists being killed every week (Haque et al., 2012). Higher crash risk is associated to the fact that driver-and rider-related factors are much more prevalent in PTW accidents compared to vehicle-and environment-related factors. In particular, there exists a clear overrepresentation of inappropriate perception in PTW crashes (Van Elslande et al., 2013). One often discussed reason for perception failures is that PTW are less conspicuous than other motorized road users (Rößger et al., 2012). Consequently, gap acceptance is often inadequate due to the size-arrival illusion (Horswill et al., 2005); the latter refers to small objects being perceived to arrive later than larger ones. Besides conspicuity, car drivers seem to encounter difficulties in understanding PTWs’ manoeuvres and, thus, fail to foresee PTWs’ behaviour; foresight is the result of the combination of circumstantial data and permanent knowledge and beliefs (Ragot-Court et al., 2012).
