A vehicle safety warning signal system for use on a bicycle, motorcycle, or like vehicle comprises: an elongate air pump (101) having a longitudinal length, the pump being provided to function as a visual warning device, such as, for example, by way of inclusion of an electrically powered light (105); and an attachment assembly configured to releasably attach the pump to the vehicle for operation in providing a visual warning signal, wherein: the attachment assembly is configured to hold the pump in at least a first position such that the longitudinal length of the pump is transverse to the main plane of the frame of the vehicle.