Evaluation of the LTL-M Mobile measurement of road marking

background, aim, method, result) max 200 words: An equipment for mobile measurement of road marking retroreflectivity, the LTL-M, has been developed by DELTA Light & Optics in Denmark. This instrument uses a different optical principle than the mobile instrument commonly used until now, the Ecodyn 30. The optical system used by the LTL-M might lead to better accuracy and repeatability. By simultaneous measurements using the two mobile instruments and, as the reference, the hand-held LTL-2000, the accuracy and repeatability of the LTL-M and Ecodyn 30 were estimated. Measurements were carried out in the laboratory on road marking samples and in the field on continuous and broken edge lines. The conclusion of the study is that the LTL-M measures with less systematic and random errors compared to the Ecodyn 30. Furthermore, the repeatability of the LTL-M is better than the repeatability of the Ecodyn 30.