The Importance of Luminous Intensity Distribution in Adaptive Road Lighting for Twin Bracket Central Arrangement

Onaygil S., Güler Ö., Yurtseven M. B.

Lux Europe 2022 14th European Lighting Conference , Praha, Czech Republic, 20 - 22 September 2022, vol.1, pp.234-237

  • Publication Type: Conference Paper / Full Text
  • Volume: 1
  • City: Praha
  • Country: Czech Republic
  • Page Numbers: pp.234-237
  • Istanbul Technical University Affiliated: Yes


To increase energy savings, adaptive road lighting (ARL) systems that can provide dynamic lighting by the change in the parameters on the road are recommended by international standards. According to CEN/TR 13201-1 “Road lighting - Part 1: Guidelines on selection of lighting classes”, adaptive road lighting is defined as “temporal controlled changes in luminance or illuminance in relation to traffic volume, time, weather or other parameters”. With the changes in the parameters considered, the initial design average luminance can be changed by reducing it, usually. The most important parameters in this respect are, traffic volume (vehicle density), traffic speed, traffic composition (motorized, pedestrian, etc.), real-time reflection properties, and the current state of the road surface.   Also, the variable effect of ambient luminosity can be considered. While applying adaptive lighting, it is also important that changes in the average lighting level do not affect other required quality parameters on the road.

When the roads with different luminaire arrangements are taken into consideration, especially roads with a median separating two directions and the poles with twin bracket arrangement are hard to design for adaptive road lighting scenarios. If both directions are to be adjusted to different levels of lighting classes, the designer should make detailed calculations since depending on the luminous intensity distribution of the luminaire, the contribution of one luminaire to the other side should be analyzed. Especially as the median width gets shorter, the contribution of the luminaire will increase. And if a one-sided dimming scheme is used, the contribution to the other side will decrease proportionally to the dim level. Thus, different luminous intensity distribution types (in 270° plane) should be analyzed for different scenarios, and energy efficiency calculations should be done using these different scenarios.

In this paper different luminous intensity distributions (in 270° plane) will be evaluated against different median widths for a sample M2 lighting class road illuminated with the twin bracket arrangement on the median. For both directions, different couples of lighting classes will be simulated using Dialux lighting simulation software ie. M2-M2 (base), M2-M4 (static), and also M2-10% (dynamic) level for no traffic “night” scenario for one side. Using the M2-M2 scenario as a base, how much the luminaires' luminous output should be increased or dimmed will be calculated and energy saving calculations for different scenarios will be done against the standard operation scenario which is M2-M2 lighting classes for both sides. As a result, depending on the 270° plane distribution of the luminaire power to be selected during the design, it will be determined how much more should be selected according to the base scenario.

Keywords—Adaptive Road Lighting, Luminous Intensity Distribution, Lighting Simulation