This European Standard specifies the requirements for individual electrically operated light devices, called warning lights, emitting a continuous or regular intermittent light of a single colour, which by their colour and position alone, are used to warn, inform or guide road users. It specifies the requirements for visual, structural and operational performan¬ces and the relevant test methods to be used. These devices rely upon existing furniture to provide the mounting. This European Standard is not applicable to lighting devices which convey messages by additional means (e.g. variable message signs) or which convey a mandatory instruction (e.g. traffic signals) or which are covered by vehicle lighting regula¬tions. This European Standard does not consider horizontal loads because it is the mounting to which they are fixed, which is not covered by this European Standard, which has to resist applied horizontal loads.