Garage doors are spring-supported, and usually operated by a switch on the wall or a remote device. Garage doors are one of the heaviest, constantly moving objects in the home, so with so many moving parts, it stands to reason that some of them will sometimes stop functioning.
Does your garage door have all the appropriate warning labels? Examples of these are spring warning labels and a general warning label. Is the manual release handle clearly distinguishable from the rest of the garage door mechanism? Keep an eye out for signs of wear and tear not only on the door itself, but also on the frame of the door and the entire mechanism.
Simple safety steps should be taken to keep you and your household safe, such as never walk under the garage door while it is moving. Children should be taught to not touch any pulleys or strings etc that relate to the garage door.
It is important to note, that if you as the homeowner see problems with your garage door, its always best to call a professional to fix the problem to make sure it is done safely and correctly.