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

This paper presents a study on the influence of the observer’s position in relation to the calculation surface. This is the initial observation of the research, respectively that the two standards consider the position of the observer differently. For these situations, two types of calculations were performed. For the first set of calculations, the software used was DIALux 4.13 as this software can perform calculations in line with the RP-08 standard. The second set of calculations was performed with a script that offers the possibility to change the observer’s position. The conclusion was that EN-13201 has a better approach, but both standards could be improved. The second case study refers to the influence of the longitudinal observer position in an average luminance calculation. If one considers RP-08 as a guideline for performing the calculations, the conclusions are that changing the distance from the observer to the calculation surface has absolutely no effect on the average luminance value. On the other hand, if European standards are used as a guideline, changing the distance (from the standardized 60 m, either closer to the calculation surface or further away) can influence the overall results in average luminance and uniformity. Taking into account the results of these two case studies, the conclusion is that both RP-08 and BS-EN 13201 should be updated so that the observer’s distance in relation to the calculation surface would be a variable dependent on the stopping distance calculated based on the speed limit of the road.