Pre-normative guidelines for photometric characterisation of road and pavement surfaces, including aging of road surfaces, wet conditions, mesopic visual conditions, and adaptive lighting systems (smart lighting)

This document deals with guidelines for photometric characterisation of pavements, in particular under certain conditions which may affect the results and/or applicability of measurements. The first part reiterates the guidelines for measurement procedures which have been reported in project deliverable D5. These procedures are intended to be used under more or less “normal” conditions. However, there are many circumstances which requires special consideration, which is dealt with in this document.

The second part discusses the impact of aging on pavement, and deals with the impact on performance when the pavement is exposed to traffic and dirt. Guidance is provided for measurement procedure in terms of when and where to make measurement on a road. The behaviour of wet pavements is of particular interest and the state-of-the-art is reviewed. The conditions of illuminance for road lighting installations are typical for mesopic conditions. However, despite this fact, all measurements are performed and all requirements are using using photopic quantities. The importance and impact of this is discussed in Section 4.

There are several aspects of spectral behaviour which may affect the performance of a road lighting installation, as discussed in Section 5. The different spectral power distributions of the light source may have an effect on the measured values and the measurement uncertainty. Section 6 discusses important parameters to consider when an adaptive lighting system is used. It is common to replace existing luminaires in a road lighting installation with modern luminaires with the ability to use adaptive control. There are many aspects to consider when doing so, as detailed in this section.

The final section deals with the development of a bidirectional reflectance distribution function (BRDF) for pavement reflectance. The model can be used for photometrically realistic simulations of the pavement.