Road lighting automation scenarios depending on traffic speed and volume B Buyukkinaci PhD a , S Onaygil PhD b , O Guler PhD b and MB Yurtseven PhD b a ISBAK Istanbul IT and Smart City Technologies Inc., Istanbul, Turkey b Energy Institute, Istanbul Technical University, Istanbul, Turkey Received 8 May 2018; Revised 31 August 2018; Accepted 3 October 2018 In this study, experimental studies that the authors have previously performed on a test road for fixed observer conditions to determine the visibility levels are extended to the moving observer position. As a result of the measurements and tests, when the vehicle speed is constant at the current speed limits for urban roads, it has been seen that the visibility level values in the calculation area remain within the acceptable limits and changing the luminous fluxes will not significantly change the visual performance of the drivers up to two lower lighting classes. It has been shown that the light level can be reduced to create two additional classes besides the current one when the traffic density decreases, at the times when vehicle speeds do not decrease. The results are applied as a case study on the Cendere Street. Road lighting classes are determined according to the EN 13201-1 Technical Report. Road lighting classes that can be applied at different times in the Cendere Street change between M3 and M5 according to the average speed of the passing vehicles, traffic density, road and ambient conditions. It is estimated that about 40% energy saving can be achieved when a lighting automation system is installed. 1. Introduction Road lighting systems are installed to allow drivers to better see the road surface and other vehicle and pedestrian movements during night time, thus enhancing traffic safety. The budget of road lighting, which is made up of the costs of energy consumption for long hours at night and lighting for many kilometres, has always been a controversial topic. For this reason, road lighting is one of the important application areas of energy- saving projects. The first step towards energy saving in road lighting is to replace the light sources in the current lighting installations with the light sources that perform the same lighting with less energy consumption, in other words, with more efficient light sources and luminaires, and to use efficient light sources and luminaires in the new installa- tions. The second step is the dimming of the light source, which requires a more complex approach. With the use of road lighting automation systems, development of accurate and efficient dimming strategies without risking traffic safety is becoming a current issue. Safety conditions in road lighting are based on the visibility of the critical object. Many of the studies and standards or recom- mendations are based on the visibility of the critical object from the location of a fixed observer. However, under real conditions, the drivers move at a certain speed and vehicle speed is one of the parameters considered in road lighting automation applications. In this study, experimental studies that the authors have previously performed on a test Address for correspondence: B Buyukkinaci, ISBAK – R&D, Seyrantepe Mahallesi Cendere Caddesi No: 56 Kagithane, Istanbul 34418, Turkey. E-mail: bbuyukkinaci@isbak.istanbul Lighting Res. Technol. 2018; 0: 1–12 ß The Chartered Institution of Building Services Engineers 2018 10.1177/1477153518812536