It has also never demonstrated a range any greater than 5 miles in independent testing. This is because compressed air has very low energy density, worse even than lead acid batteries.

Compressed air / gasoline hybrids make good sense though, as the low energy density of compressed air is not a problem if it's only being used as a way to recapture braking energy, then reuse it to accelerate the car. The air tank and other hardware to do this is cheaper than the batteries and electric motor in conventional hybrids. Peugeot has been working on this for some time.