This European Standard specifies the functional safety requirements for traffic signal controllers. It is applicable to traffic signal control equipment permanently and temporarily installed, and portable traffic control equipment, with the exception of portable traffic signal equipment capable of controlling only alternate / shuttle working lanes (as further defined in 3.37), without the control of crossing vehicular or pedestrian movements. Traffic signal controllers, as defined by this European Standard, are required to control conflicting traffic, both vehicular and pedestrian, e.g. junction signals, pedestrian crossings, shuttle signals, public transport signals, in a safe manner. The electrical safety requirements and additional traffic safety requirements, the interfacing with external equipment and the test methods for verifying compliance with this European Standard are contained in EN 50556. For a full applicability of this European Standard as well as of the EN 50556 the national standardization bodies are requested to define the set of classes relevant for their national requirements. NOTE National requirements may specify special conditions for public transport signals (PT) and for any other signal that is not specified in a European Standard.