a safety pole is comprised of a strip of plastic material having a normal elongated hollow cylindrical condition with overlapping longitudinal edges . a motor driven drum is mounted within a canister adapted to be recessed in the ground in spaced relation to a loading dock with the strip of plastic material connected at one end to the drum whereby the strip of plastic material may be wound on the drum in a flattened condition or extended vertically upwardly to form a pole . a loading dock is provided with a door and the operation of the motor driven drum is coordinated with the operation of the door so that when the door is open , the pole will be in the extended visible condition to warn a truck driven not to approach or leave a loading dock .