The literature review was made on commission by the Nordic collaboration NMF (Nordic meeting for improved road equipment). The commission was on synthesising knowledge of and regulations for post delineators in the Nordic countries. The review started with a broad approach where all literature on post delineators was searched in the databases TRAX and ITRD. After sorting out some of the material some references were ordered, after which a new sorting out was carried out along with supplementing the material with other references. In total, this report includes 31 references. The literature review consists of three parts: - Road user effects of post delineators. - The function of post delineators. - Regulations for post delineators in the Nordic countries.