One aspect of the invention provides an ion-conducting membrane comprising an ion-conducting region and a non-ion-conducting region. When the mirror assembly is attached to the side of the vehicle and when the light source is electrically powered, light emitted by the light source illuminates a ground area adjacent the vehicle of at least approximately 2 feet by 4 feet. The assembly has essentially no peripheral cover fitted thereto. The roller bodies have axial ends which engage in an annular slot of the wheel.