40-6-75.
   
  (a) The driver of a vehicle shall yield the right of way to any
  authorized vehicle or pedestrian actually engaged in work upon a
  highway within any highway construction or maintenance area
  indicated by official traffic-control devices.
   
  (b) The driver of a vehicle shall yield the right of way to an
  authorized vehicle actually engaged in work upon a highway whenever
  such vehicle displays flashing or revolving amber lights and has a
  permit to use such amber lights.