The UK study says “misperception of vehicle approach speed” is a key contributory factor in SMIDSY (Sorry mate, I didn’t see you) motorcycle crashes.
There has been research in the past that shows the smaller the vehicle the more the other motorists perceives their speed to be slower than it actual is and to perceive the coming vehicle as less of a threat. This is one reason why motorists tend to drive out in front of an approaching bike.
The UK researchers investigated drivers’ judgments of motorcycle and car approach speeds with different levels of lighting, including motorcycles with triple headlights, such as some touring motorcycles.
“The accuracy of car approach speed judgments were not affected by changes in lighting conditions, but speed judgments for the solo headlight motorcycle became significantly less accurate as lighting reduced in the early night and night-time conditions,” the study found.
“Incorporation of a tri-headlight formation on to the standard motorcycle frame resulted in improved accuracy of approach speed judgments, relative to the solo headlight motorcycle, as ambient light levels reduced.
Based on their findings, the WHO report recommends motorcyclists, scooters and other powered two- and three-wheeled vehicles should be fitted with triangulated headlights.
Or maybe it’s best to accompany two friends on bikes each with a single headlight and ride in a triangulated formation.