Abstract: A foldable triangular traffic signalling device including a collapsible body having first, second and third leg members connected together for movement between an erect triangle forming position in which each leg member constitutes one leg of a triangle and a folded position. One of the leg members has a pair of spaced sidewall members, and the other leg members each have an inner end received in the space between the sidewall members and pivotally connected to the sidewall member such that the other leg members can be folded and stored within the space between the sidewall members when the device is not in use. Light reflective means is provided on the outer surface of the leg members to define a triangular warning device when the leg members are in their erect position.