People are more likely to die in fatal road accidents on nights with a full moon, a study reveals.
Researchers believe the glowing allure of the once-monthly spectacle distracts motorists for crucial seconds and may also prompt them to drive faster.
The study analysed fatal motorcycle collisions which took place over a 30-year period in the UK, United States, Canada and Australia, comparing the number occurring on the night of a full moon to nights one week before and one week after.
The study, published in the British Medical Journal, found the risk of death from driving was around 5 per cent higher during a full moon.
The added danger was significantly higher - 27 per cent - during a supermoon, which occurs when the distance between the satellite and the Earth is about 13 per cent less than normal, making the object appear larger and brighter.
Supermoons take place roughly five times a year and the next is expected on January 1.
"A full moon is infrequent and spectacular, thereby creating a natural distraction," the authors wrote.
"It can appear abruptly to a motorcyclist, such as when riding around buildings, through turns, past trees, and over hills. A full moon also creates optical illusions that engender wonderment and tends to rise above the horizon in the night hours exactly at the time motorcycle crashes generally predominate."
The scientists at the University of Toronto and Princeton University noted previous research indicating that the three factors most likely to distract attention are an object of large size, brightness and an abrupt onset, all characteristics of a full moon.
"Beyond these, a full moon might contribute to increased outdoor activity of all types, including more frequent travel, faster speeds, longer distances, unfamiliar routes, added cross traffic, and mixtures of less experienced travellers," they said.
In folklore, full moons have been associated with insanity, but despite a plethora of studies no reliably consistent parallels have been drawn.
However, a study in the BMJ 17 years ago did indicate that dog bites in the UK are more common during a full moon.