Abstract: A boom-type spraying apparatus which is automatically leveling during usage in spraying materials adjacent highway fixtures such as guard rails, the apparatus provides a means for automatically controlling the level of the spraying apparatus regardless of changes in lateral or vertical movement of the vehicle carrying the reservoir of material, the spraying apparatus including preferably two boom arms which are pivotally secured to a vehicle, the boom arms preferably each include an inner end and an outer end which telescope with respect to one another and are spring biased to allow this telescoping movement, the apparatus further including a roller construction at the outer end of the boom arm which is mounted upon a spindle at the end of the boom arm such that as the vehicle travels along the road the roller will follow the guard rail therealong and as such will hold the spraying conduit and spraying head in the proper orientation for application adjacent the guard rail, the roller configuration may include