If you're driving with unlocked doors, you never know who'll try to get in -- or out, police say.
"There've been incidents where doors have gone open while the vehicle was in motion because a child pulled on the handle," says Ottawa Police Const. Chuck Benoit. "There've also been incidents of forcible confinement -- where a person enters the vehicle while you're stopped or driving slowly in traffic and takes over."
It's a good idea to drive with doors locked, police say.
"We recommend it," Benoit says. "But there's no rule or law that says you have to."
Ford Canada says automatic locking is a safety feature. If it's turned on, doors will lock when you're driving faster than 20 km/h.
"The locks will unlock when the driver's door is opened," says spokesperson Rose Pao in an email. "In the event of an accident where air bags are deployed, the door locks will unlock automatically."
In a car crash, the doors need to stay closedbecause they absorb the impact, keep you from being thrown out, and help keep the roof from crumpling like a soda can. Locks might help, police say.
"If the vehicle does roll over, the lock is a secondary means to ensure that the door stays closed," says Ontario Provincial Police Sgt. Peter Leon.
And, even if you're driving with unlocked doors, you could still be trapped in a crash anyway.
"When there's an impact, a lot of time the doors are pushed in and don't open," says Ottawa Police's Benoit. "Whether they were locked or unlocked, the impact damaged the door and made it jam anyway."
Rescue workers will have to get you out -- or you'll have to break out yourself.
"There are glass-breaking tools available, automotive companies carry them, and they'll break the glass very easily," says Leon. "They do come with a cutting blade that would let you cut your seatbelt if you needed to."
In the movies, most car crashes end in a deadly blaze, but U.S. statistics show that only about four per cent of motor vehicle deaths happen in fires, says the Canada Safety Council.