The fact that motorcycles are less common than cars might make it harder for car drivers to see motorcycles, said researcher Vanessa Beanland, of the Australian National University, and colleagues.
They used a driving simulator to study the ability of 40 adult drivers to detect and respond to motorcycles and buses on the roads. During the driving simulations, half of the participants were shown a high number of motorcycles and a low number of buses, while the other half of the participants were shown the reverse.
All of the participants were told to watch for both motorcycles and buses. However, their attention tended to favour whichever of the two vehicles they saw more often during the driving simulation, and this affected the speed at which they detected the vehicles.
Participants who saw motorcycles more often were able to detect them an average of 167 feet farther away than those who saw motorcycles less often. At a driving speed of 37 miles per hour, this gave the drivers an extra three seconds to respond.
At the same speed, drivers who saw buses more often had an extra 4.4 seconds to react to buses, according to the study, which was published recently in the journal Attention, Perception & Psychophysics.
Vehicles and hazards that are rare
The findings suggest that drivers often fail to see motorcyclists partly because motorcycles are not common on roads, and drivers aren't on the lookout for them, Bean land said in a journal news release.
"Drivers have more difficulty detecting vehicles and hazards that are rare, compared to objects that they see frequently," she said.