File picture: Vincent West / Reuters.

London - There are more fatal motorbike crashes on nights when a full moon is out, a study found.

Experts believe the sight appearing suddenly from behind a building or over a hill is a hazard for motorcyclists as it distracts them with ‘wonderment’ - causing them to take their eyes off the road. A study analysing fatal crashes over three decades in the UK, US, Canada and Australia found an additional death for every two nights when there is a full moon.

On nights with a ‘supermoon’, which appears larger because it is closer to Earth, the chance of motorcyclists dying is even higher.

The study authors, led by Dr Donald Redelmeier at the University of Toronto, highlight the importance of constant attention when riding, as momentary distraction is a common contributor to road deaths. Other major factors are not wearing a helmet and road defects.

In Britain, where 1414 fatal motorbike crashes took place between 1975 and 2014, 309 happened on nights when there was a full moon – a 6 per cent increase in their frequency.

The study, published in the BMJ, states: "We hypothesised that because people’s attention is naturally drawn to a full moon, it might contribute to fatal motorcycle crashes. In particular, glancing at it takes the motorcyclist’s gaze off the road, which could result in loss of control."