THE majority of the white lines applied to road surfaces for aiding traffic flow are prepared with white paints made from pigmented solutions of Manila resin in alcohol; such paints are the subject of Specification BS/ARP 38. Attention has recently been given to alternative white–line materials by the Paint Research Station and the Road Research Laboratory. According to Roads and Road Construction of September, one of the most promising alternatives is a thermo–plastic material applied hot to the road surface as a thin layer which sets hard on cooling. This type of material has the advantage that its set does not depend on evaporation of a volatile constituent; it hardens rapidly, allowing traffic to pass over it within a few minutes of application. It has good wear resistance and maintains a reasonably white colour. Thermoplastic materials of a proprietary type have been subjected to road tests during the past two years and in some instances have given satisfactory results. The composition now described is suitable only for open– and medium–textured road surfaces which provide a certain amount of key or mechanical grip. It may be applied to an existing road surface without insetting. A specification has been drawn up for the manufacture and application of the composition.