Garage doors have a history of causing injury. Over the years, several safety features have been added to garage door openers to reduce the probability of injury. Residential garage doors are equipped with safety eyes and a reversal mechanism.
If your door is closing, any obstruction that moves through the doorway should be detected by the safety eyes. Federal Legislation in 1993 mandates all garage doors be equipped with safety eyes. The safety eyes will trigger the reversal mechanism and send the garage door back up.
The safety reversal mechanism will also be triggered if the garage door opener detects tension, or a physical object is blocking its path. To test the reversal mechanism, place a 2×4 in the door way flat side down. The 1.5 inches of wood should be enough to tell the door to stop closing and raise the door. If your door does not return to the open position, you know it is time to have a garage door technician come and adjust your equipment.