Self Controlled Car Speed Restrictor

  The "NO-SPEEDY CD" device replaces your regular in-car CD player. But the "NO-SPEEDY CD" player is driven by a series of belts, chains and sprockets from the front wheels of your vehicle.
  Now go and buy your favourite CDs in various speed formats, and pop in the appropriate format dependant on the speed restrictions youre driving within.
  Hey presto, youre in a built up area and you've got your 30mph version of Steps playing. If you start to go too fast, they sound dreadful and you slow down to a more suitable speed.