Review of road surface photometry methods and devices – Proposal for new measurement geometries

Abstract

Specifications concerning road lighting and photometry of road surfaces were established more than 50 years ago. Road lighting design and road marking visibility were developed for vehicle driving. The observation distance defined by standards corresponds to interurban applications; however, within Europe these areas do not tend to be lit. The objective of the SURFACE project is to propose new geometries for the photometric characterisation of pavements, both adapted to different urban travel modes and new lighting technologies. This article reviews the available guidelines, standards, measuring devices and literature regarding geometries and road lighting applications, and presents the project SURFACE analysis and proposal. The SURFACE consortium recommends adding several new angles for different driving conditions and road users; 2.29° for urban environments and consistency with road marking standard, and 1° for extra-urban environment and consistency with previous geometries. A 5° angle, corresponding to 17-m viewing distance, could be an interesting compromise, suitable for urban driving at low speed, cycling and for scooters. The angles of 10° and 20° are under consideration for describing the boundary between diffuse and specular behaviour.

Average Luminance Calculation in Street Lighting Design, Comparison between BS-EN 13201 and RP-08 Standards

“…After a detailed comparison, we observed that the main difference between the two standards is the observer positioning, which, as other papers suggest [16], can have a significant influence on the average luminance value due to the reflection properties of the asphalt [17][18][19]. Considering this, the second section of the paper presents an overview of the differences from the two standards and a case study, for three particular roads in which the average luminance values are compared when calculated with the same input data, but as per the two standards.…”

“…According to [16], changing the angle of observation directly affects the average luminance on a road. They also conclude that the European standard needs to be updated in order to add extra angles of observation according to the type of road.…”

Influence of Pavement Heterogeneity and Observation Angle on Lighting Design: Study with New Metrics

“…To study the spatial heterogeneity of pavement reflection properties, photometric evaluation was performed on-site with a portable measurement device named COLUROUTE [27,36] (picture on the left in Figure 4), which complies with the specifications of the CIE [13]. The luminance coefficients of the road surface are measured on-site, in daylight, and without sampling.…”

“…This implies characterizing the pavement reflection properties from angles other than the conventional 1 • . It also implies adapting the methodology for dimensioning and measuring the performance of a lighting installation by systematizing the use of luminance [27,28]. For the classical calculations at 1 • , the observer is fixed and located 60 m in front of the calculation zone [9,29].…”

“…Indeed, an r-table measurement is often punctual. For example, the measurement is carried out in the laboratory with a gonioreflectometer on pavement samples, either new or obtained after coring the pavement [27,35]. In the latter case, two areas on the road are usually chosen: one in a wheel track and another in the central track (between the two-wheel tracks of the lane).…”