Section 31
SEC. 31. Every motor vehicle operated on any public highway shall be provided with brakes adequate and efficient at all times and with a horn or other signaling device approved by the Director of Public Works or his deputies. No horn or signaling device emitting sounds of an exceptionally loud or startling or disagreeable nature shall be approved by the Director of Public Works or his deputies for any purpose other than police patrol wagons, fire wagons and engines, ambulances, and automobiles and motorcycles especially designated and assigned by the Director of Public Works for the purpose of enforcing the provisions of this Act.