Two people were seriously hurt in two separate scooter accidents this weekend in Mission Beach, police said.

A 62-year-old man fractured his neck Sunday afternoon when he lost control of his scooter on the 3800 block of Bayside Walk, near Mission Bay Sportcenter, according to the San Diego Police Department.

The man fell head first onto the sidewalk around 12:30 p.m., Officer Dino Delimitros said.

Surveillance video obtained by NBC 7 showed the man fall forward as the scooter went down. A group of people rushed to help the man before medics arrived.

Hours earlier on Saturday night, a 39-year-old man sustained a life-threatening injury when he fell off his scooter on the Mission Beach Boardwalk near Belmont Park, the SDPD said.

The man was riding the southbound on the 3300 block of Oceanfront Walk around 10 p.m. Saturday when he veered to his right and fell, Officer Robert Heims said.

The man sustained a severe head injury when he hit his on the ground, Heims said.

Both men were transported to area hospitals for treatment.

These two accidents are the latest in the string of fatal and near-fatal crashes involving scooters since dockless scooters were allowed to operate in the city in February 2018.

A recent study by UCLA researchers, which looked through medical records at two hospitals in Los Angeles, found that head injuries were the leading cause of scooter injuries.

The study found that 40 percent of the people injured at head injuries. The results suggest there were low rates of adherence to existing regulations with regards to a rider’s age and low rates of helmet use, the study's authors said.

In California, motorized scooter riders must be at least 16 years old and have a driver’s license or permit.

Riders are also not allowed to ride scooters on sidewalks. Scooters, however, are allowed on the Boardwalk.

A lawsuit filed earlier this month against the city of San Diego and Bird, a dockless scooter operator, is asking for changes, namely geo-fencing that would prevent scooters from being operated on sidewalks, parks, and similar areas.