Road Markings for Reliable Visual Guidance and Sustainability

Road markings—inalienable elements of almost all paved roads worldwide responsible for the safe guidance of drivers—are described from the perspective of materials. The characteristics of road markings as dual-layer speciality industrial maintenance coatings, along with their key performance parameters, are explained. Results from field and laboratory evaluations of various materials are utilised to present the key issues associated with the visibility of road markings for both human drivers and machine vision equipment. The topic of sustainability is addressed based on the outcome of field tests; the carbon footprint of representative materials from a long-term perspective (i.e., a series of renewals to maintain the properties, as is appropriate in cases of deteriorating systems) is given. The issue of microplastic emissions is discussed; the newest results are used to demonstrate the inadequacies of earlier theoretical estimates. Emerging concepts, such as luminescent road markings, are criticised due to low practical applicability. Good practice recommendations to maximise the properties for road users are given as a reference for road administrators and scientists.