After two serious collisions involving all-terrain vehicles in the Edmonton area, one of them fatal, police are warning operators of the vehicles to be safe, and follow the rules.

The first of two incidents happened Wednesday evening just before 7, when two ATV riders were driving their vehicles on private property, Yellowhead Aggregates located on 137 Avenue and Meridian Street in northeast Edmonton.

One of the riders drove his ATV up a large sand pile, then plunged down the other side – falling about 20 metres (65 feet) to the ground.

Although the other rider immediately called 911, there was nothing EMS crews could do to save the 38-year-old man.

"Emergency Medical Services were the first on scene," Sgt. Chris Edge said. "They were able to immediately determine that the male was deceased."

The rider had been wearing a helmet at the time of the crash.

Less than a day later, police were called to another collision involving an ATV.

Just after 1:30 pm Thursday, police and Emergency Medical Services personnel were called to 89 Street and 125 A Avenue, a service road running alongside Yellowhead Trail – after an ATV collided with a car.

Investigators said a 25-year-old woman was riding an ATV eastbound on the service road, when the vehicle struck a car, which was stopped at a light on 89 Street, waiting to turn onto Yellowhead Trail.

"Unfortunately she was not wearing a helmet," Cst. Walter Kubrak said Thursday. "She was thrown from the ATV onto the hood of the car, and then bounced off that hood and landed on the ground."

The driver was treated on the scene, and then rushed to hospital with serious injuries.

Police said charges are pending against the driver, and the ATV has been seized.

A spokesperson for the Centre for Injury Control said incidents involving the vehicles are common.

"Our notion of an all-terrain vehicle being something that can go anywhere and do anything is kind of a misnomer," Kathy Belton said. "These machines are not all that stable."

Police are using both of those incidents as reminders to those using the vehicles of the possible consequences of using the ATVs incorrectly – the vehicles are only allowed on private property, with permission.

"If you are caught on a city street with one of these vehicles, police are likely to seize it," Cst. Steven Levesque said Thursday. "The simple matter is that you are not allowed to have it on the street."

Investigators from the Traffic Section are working on both incidents.

With files from Sonia Sunger