In the traffic laws, the use of the car horn, made ​​such Speaker

1, motor vehicle approaching sharp bends, etc. affect the safety of the top of the ramp sections and overtaking sight or the event of an emergency, should slow down and honk to indicate.
2, the front of the vehicle in case the vehicle is parked or driving slowly while waiting in line, waiting or turn driving bookshelf speaker not enter non-motor vehicle lanes, sidewalks driving, urging shall honking vehicles and pedestrians.
In other words, the role of car horns, is a special section of the advance warning, the warning of some emergency Multimedia Speaker, in order to ensure traffic safety.