Abstract: An automatic retractable delineator with a housing containing a reciprocating delineator post that reciprocates through an opening in the top surface of the housing. A raising and lowering mechanism is disposed inside the housing and is mechanically coupled to the post. The housing defines an inside cavity that is provided with positive pressure to create a pressure differential between the cavity and the atmosphere. As a result, the housing is substantially protected from the elements as the pressure differential prevents foreign objects and moisture such as dirt, salt, ice, snow or the like from entering the cavity.