Denver’s independent monitor office is evaluating whether the city needs more stringent restrictions on when police officers can shoot at moving vehicles.

The decision comes after a teenager was shot and killed by police while she was in a stolen car. Police say two Denver officers opened fire after one of them was struck in the leg by the vehicle.

"Most progressive police departments have policies that restrict the ability of officers to shoot at a moving vehicle," said Geoffrey Alpert, professor of criminology with the University of South Carolina. 

"It’s a very dangerous practice because you don’t know where the vehicle is going to go if you are successful in shooting the driver," he added.

The U.S. Supreme Court has held that officers may not use deadly force to stop a fleeing suspect unless the person is believed to pose significant physical harm.

Alpert says officers could be allowed to open fire if they face a serious, imminent threat, like someone in a vehicle firing at them. But they also should retreat if possible when a vehicle is being used as a weapon. 

A passenger in the car has disputed the official account of Hernandez's death, saying police opened fire before the vehicle struck the officer.

The Associated Press contributed to this report.