Other Answers (3)

• Compressed air cars do run on compressed air, but no illusions, the compressors have to be powered by some form of energy, whether that is from a nuclear or coal power plant, or from wind power... whatever we have to power them.
  
  In a real sense this is like using compressed gas as a battery that we charge up to propel the vehicle.
  
  It is possible to reduce automotive pollution in congested areas using this concept, same as with an electric car. It moves the pollution out to the place we are doing our compressing, which may be our suburban driveway if we run a compressor on a gasoline engine, or back to the power plant if our power plant burns coal.
  
  Best make sure our electrical generation is all clean green technology, or nuclear before we start deploying this.
• Remember you will only get the energy back out that you put in. The air has to be compressed in the first place so through compressing the air and then using the air to run the car some energy is lost in the energy transfer. Net to net it would have to be less efficient than using the same amount of fuel to just run the car.
• i have seen one on discovery channel. it is going to be released on 2018 worldwide they are hoping.