A functional description is given of delineation systems used in work zones. Based on a theoretical analysis predictions are made about the effectiveness of particular delineation systems as a reference in perceiving course and speed. Furthermore, a laboratory experiment is described, in which the effectiveness of a number of delineation systems as a means of preview guidance was investigated. It is concluded that delineations which are mounted at eye height function poorly and that improvements can be reached by lowering the delineation. In addition, it is concluded that the use of a chevron configuration on panels may be particularly effective in conditions where panels are placed somewhat haphazardly or when only a limited number of panels is used.