Microprocessor-controlled light emitting diode (LED) arrays are built into an extruded tubular lens within a mast that is connected to a base assembly. A means of mounting, which may be an adjustable clamp, permits the base assembly to be connected to a seat post or other mounting point on a bicycle or other vehicle. The tubular lens allows for substantial dispersion of light, and various light patterns produced by the arrays may be selected and those patterns alternated automatically to achieve greater visibility of the vehicle to surrounding motorists. A handle within the base assembly allows a rider to lower the mast from its vertical operating position easily and pivotally up to 90 degrees parallel to the longitudinal axis of the vehicle frame to facilitate mounting and dismounting the vehicle.