An investigation on multi-vehicle motorcycle crashes using log-linear models

Abstract

Motorcyclists are the most crash-prone road-user group in many Asian countries including Singapore; however, factors influencing motorcycle crashes are still not well understood. This study examines the effects of various roadway characteristics, traffic control measures and environmental factors on motorcycle crashes at different location types including expressways and intersections. Using techniques of categorical data analysis, this study has developed a set of log-linear models to investigate multi-vehicle motorcycle crashes in Singapore. Motorcycle crash risks in different circumstances have been calculated after controlling for the exposure estimated by the induced exposure technique. Results show that night-time influence increases crash risks of motorcycles particularly during merging and diverging manoeuvres on expressways, and turning manoeuvres at intersections. Riders appear to exercise more care while riding on wet road surfaces particularly during night. Many hazardous interactions at intersections tend to be related to the failure of drivers to notice a motorcycle as well as to judge correctly the speed/distance of an oncoming motorcycle. Road side conflicts due to stopping/waiting vehicles and interactions with opposing traffic on undivided roads have been found to be as detrimental factors on motorcycle safety along arterial, main and local roads away from intersections. Based on the findings of this study, several targeted countermeasures in the form of legislations, rider training, and safety awareness programmes have been recommended.

How similar are two-unit bicycle and motorcycle crashes?

“…Driver failure to see two-wheelers, difficulty in determining motorcycle speeds, and reduced conspicuity of two-wheelers have been identified as important causes of 'failure to give way' type crashes in many studies (e.g., Haque et al, 2012;Horswill et al, 2005;Pai, 2011b;Pai et al, 2009). While driver attention is important, improving conspicuity of riders by using illuminated lights, wearing reflective clothing, and using retro-reflective marking on helmets and two-wheelers could potentially improve rider safety.…”

“…Smaller size and less intensity of bicycle lights could explain why drivers failed to give way to bicyclists more often at night than motorcyclists. Increasing the conspicuity of riders and two-wheelers to improve safety has been recommended in a number of studies (Haque et al, 2012;Pai et al, 2009;Thornley et al, 2008;Wood et al, 2009;Yuan, 2000). In addition to headlight (static or blinking), reflective vest, and reflective markings on two-wheelers, researchers (Wood et al, 2012) have suggested use of ankle and knee reflectors for bicyclists.…”

“…Mandatory use of daytime motorcycle headlights was found effective in reducing motorcycle crashes (Elvik et al, 2009;Yuan, 2000). However, night-time conspicuity improvement treatments, such as retro-reflective vests and markers, were found to produce mixed findings for motorcycles, as identified in Haque et al (2012). For bicycles, on the other hand, use of reflective vests and markers (Thornley et al, 2008;Wood et al, 2009) and ankle and knee reflectors (Wood et al, 2012) were found to be generally effective.…”

“…This rather surprising finding warrants further investigation. It might reflect more driver failure to see motorcyclists (Haque et al, 2012) and more common failure by motorcyclists to react to drivers because motorcyclists are travelling more quickly than bicycle riders. Alternatively, police may be more likely to identify violations in motorcycle crashes because they perceive that sanctions would be easier to apply to drivers and motorcycle riders than bicycle riders (who do not have the threat of losing their license).…”

“…The limited conspicuity of bicycles and motorcycles and consequently drivers failing to see them or giveway to them have been identified as contributing factors in many studies (e.g., Haque et al, 2012;Horswill et al, 2005;Pai, 2011b;Pai et al, 2009), which implies that there might be similarities between bicycle and motorcycle crashes, particularly at give-way situations. Other authors have suggested that drivers' perception of motorcycles as less threatening than other large vehicles may also contribute to them failing to give way (see Pai, 2011a).…”