This European Standard specifies requirements for Road Traffic Signal Systems, including their development, design, testing, installation and maintenance. In particular, it forms the electrotechnical part of the following two standards issued by CEN: EN 12368 Traffic control equipment - Signal heads EN 12675 Traffic signal controllers - Functional safety requirements Each of these standards above shall be used with this standard either singly or together to define an operational equipment or system. This shall be achieved by using the electrotechnical methods and testing defined in this standard. Where Road Traffic Signal Systems are to be used with other systems e.g. public lighting or railway signalling and communication, this standard shall comply with the other respective standard to ensure that overall safety is not compromised. Only permanently or temporarily installed Road Traffic Signal Systems are included in this standard. Central office and portable signalling systems are not covered.