PHILADELPHIA (CBS) –- A female Philadelphia police officer was taken to the hospital this morning after being pinned between two cars during a traffic stop.

The incident happened about 9:30am at 63rd Street and Grays Avenue in Southwest Philadelphia.

Police spokeswoman Tanya Little says that as the 12th District officer exited her patrol car to check out an unoccupied vehicle, she apparently failed to put the her own vehicle in “Park” or put on the parking brake, and it began rolling toward her.

In an instant, investigators say, the moving patrol car trapped her against an approaching SUV.

The officer suffered an injury to her right leg and was listed in stable condition at the Hospital of the University of Pennsylvania.

Officials say no charges will be filed against the driver of the SUV, who was allowed by police  to leave the scene.

The incident remains under investigation.