Motor vehicles, trailers, and semitrailers, when temporarily stopped on the traveled or paved portion of the highway so as to create a traffic hazard, shall flash all four turn signals simultaneously to signal approaching motorists of the existing hazard whenever such vehicle is equipped with a device which will cause the four turn signals to flash simultaneously. All four turn signals may be flashed simultaneously on a vehicle slowed or stopped at the scene of a traffic hazard, when traveling as part of a funeral procession, or when traveling at a speed of thirty miles per hour or less. Except for vehicles traveling as part of a funeral procession, all four turn signals shall not be flashed simultaneously while the vehicle is traveling faster than thirty miles per hour.

School buses shall flash all four turn signals when approaching and stopping at railroad grade crossings.