An ambulance transporting a woman injured in a car crash was slowed on its way to the hospital because of a tailgating vehicle, paramedics said.

Paramedics said a car collided with a tree on Highway 417 at Boundary Road around 3:12 p.m. Thursday.

A woman in her 20s, who paramedics say may have been ejected from the car, suffered multiple injuries, including a fractured leg.

She was stabilized by paramedics on the way to hospital. Paramedics said she is in serious but stable condition.

The trip to the hospital was delayed, paramedics said, because of a vehicle following too closely behind the ambulance, increasing, they said in a tweet, "the risk of collision."

"Never follow an emergency vehicle with lights and sirens," the service tweeted from their Twitter account.