Why do I always see white plastic bags on people's cars when they're parked on the shoulder?

Question

What does this mean and why are they there, particularly when there's no one in them?

Answer 1

They are used for a safety reason just like flares are but will last longer, they notify passing cars and the police that the car is having problems.......

Answer 2

Maybe your local law enforcement puts them there to let other officers that the car has been called in and the 24 Hr. rule goes in affect.If the car is on the highway more than 24 Hr. than it will be towed to the impound yard.I hope this helps.

Answer 3

it means they need help.

Answer 4

hanging a white rag out a car window on the side of the road means "I need help."  If you don't have a white rag, a white bag wll work.  Maybe the cars with no people in them mean someone stopped and gave them a lift.