A system for the automated determination of retroreflectivity values for reflective surfaces disposed along a roadway repeatedly illuminates an area along the roadway that includes at least one reflective surface using a strobing light source. A donut-shaped heat exchanger is located within the housing between the compressor wheel and an outlet from the housing and has radially inner and outer peripheries. A low coercivity and high magnetic permeability can be obtained. The stent is, for example, an apertured tubular member formed of a polymer and is assembled about the balloon. Each base station adjusts its gain of the forward traffic channel in accordance to its measurement of the forward link power control bit.