Many parents look at four-wheel, all-terrain vehicles and consider the dangers they pose to kids. In reality, there’s another hazard for children who ride off road: motorcycles.

Researchers in Australia recently found that motorcycles accounted for more than three times as many injuries as four-wheel vehicles. To determine that, they analyzed nearly 20 years of medical records for children injured in off-road motorcycle and quad-bike crashes.

Just more than 6,600 children required hospitalization for their injuries. Of those cases, 78% were motorcycle crashes while 22% involved quad bikes. Among the 10 fatalities reviewed by researchers, six were motorcyclists and four involved quad bikes.

Two-wheel and four-wheel vehicle riders also were likely to suffer different types of injuries. Quad-bike riders were more prone to have head, neck or abdominal injuries. Lower-limb injuries were common among motorcyclists. On average, quad-bike riders had more severe injuries and longer hospital stays than motorcycle riders.

The researchers suspect several factors affected the crash numbers. In Australia and many other countries, off-road quad bikes have long been scrutinized for safety. Public-awareness campaigns that emphasize a minimum riding age may have helped to make riders more cautious. It’s also possible that significantly more children ride motorcycles than quad bikes.

Next, the researchers want to better understand the many factors affecting the number of crashes. Ideally, they said, off-road motorcycles used by young riders could get the same design and safety scrutiny as quad bikes.

For young riders, the message is simple: Throttle down and stay in control.