16 NRM02 Final Publishable Summary
Creators: name: Paola, Iacomussi
Publisher: name: Zenodo
Year: 2021

description: Final publishable summary of project 16NRM02 SURFACE Across Europe about 40 % of the 5.5 million kilometres of roads have lighting. Current EU standards on road lighting (i.e. EN 13201 series) seek to establish road luminance values able to satisfy quantitative and qualitative performances in terms of safety, visual appearance, and energy consumption. Thus, the weighting and spacing of a road lighting system (i.e. luminous flux installed per kilometre) are calculated accordingly, to comply with the suggested luminance values of the assigned road class that warrant the visibility for road users’ safety. Usually, the design of such lighting systems (e.g. the definition of the installation layout, luminous intensity, distribution of luminaires, and luminous flux installed per kilometre or power density indicator) considers reference weighted q data (r-tables) of the road surface. In the EN 13201 Road lighting Standard series, r-tables provide values only for the necessary incident and view directions for traditional lighting installation (i.e. installation luminaires height greater than 10 m and columns inter-distance of about 30 m) and the q data, representative of the road surface behaviour, for those directions are missing. Road lighting designers adopt as de facto, standard values, the r-table or the equivalent q values published in CIE documents. However, these data are based on measurements performed on concrete samples more than 40 years ago without traceability and uncertainty evaluation. Recent studies have shown that the use of CIE data as reference, leads to large errors (on average over 30 %, but up to 50 % in worst case) on expected road luminance. Moreover, the photometric properties of road materials have changed over time due to new material components and laying techniques as well as the road lighting systems (i.e. LED sources, adaptive systems and smart lighting systems, and luminaires installed at lower heights). Such an evolving situation requires the definition of new values of q and an upgrade of the reference directions for its measurement. To ensure EU targets on Energy Saving and Road Safety are met, the project focussed on improving q reference data and reference geometries through a large metrological research review of basic concepts and metrological capabilities. After the 1st CIE international symposium on Road Surface Photometric characteristics (Torino, 2008), the revision of CIE TR 144 was set up in 2009, however no significative advances were made due to the lack of focused research, NMI involvement, and of collaborative approach within all involved figures. Owing to the project’s achievements, CIE TC4-50 is finally able to attain its task. A new CIE TR144 has been planned in for the next years and will based on the SURFACE pre-normative guidelines and results. Objectives The goal of this project was to address the current deficiencies in European Standards regarding (i) the definition and characterisation of the road surface photometry, (ii) traceable measurement and characterisation methods for road surface characteristics and (iii) traceable reference data for photometric tables useful in the design process of road lighting installations. The project results will be used by CEN TC169/WG12 in the next revision of EN 13201 series, and by CIE TC4-50 in the revision of pertinent CIE publications. The specific objectives were: To develop optimised measurement geometries for the characterisation of photometric quantities for road surface materials to support EN 13201 ‘Road Lighting’ and its future revisions. To produce technical and metrological specifications for instruments used to measure luminance and reduced luminance coefficients of road surfaces in laboratories or on-site, including methodologies for calibration, establishing traceability and evaluating the measurement uncertainty. To develop pre-normative guidelines for measurement methods and procedures, for the future evolution of European standards to include aspects such as mesopic visual conditions (CIE191:2010), reduced obtrusive light and reduced light pollution of road lighting installations. To develop pre-normative guidelines for photometric characterisation of road and pavement surfaces, including factors such as aging of road surfaces, wet conditions, spectral properties, diffusion of adaptive lighting systems (smart lighting), luminaire luminous intensity distribution and effects of measurement uncertainty in tolerance calculations. To contribute to the standards development works of the technical committees CEN TC169/WG12 and CIE TC4-50 through the provision of data, methods, guidelines and recommendations. In particular traceable data related to new geometries and materials for inclusion in updated photometric tables of pavements in the international CIE database shall be provided. To ensure that the outputs of the project are aligned with their needs, results will be communicated quickly to those developing the standards and to those who will use them (e.g. lighting engineers, road designers), and in a form that can be incorporated into the standards at the earliest opportunity.