City of Peoria, Illinois
The City has an Ordinance which addresses this issue: Sec. 15-66. Horns or signalling devices on vehicles. No person shall allow or cause to be blown any horn or signalling device on any automobile, motorcycle, bus or other vehicle on any street or public place of the city, except as a danger warning; the creation by means of any such signalling device of any unreasonably loud or harsh sound; the sounding of any such device for an unnecessary and unreasonable period of time; the use of any signalling device except one operated by hand or electricity; the use of any horn, whistle or other device operated by engine exhaust; the use of any such signalling device when traffic is for any reason held up. Individuals who are aware of taxis which violate the Ordinance are welcome to file a complaint with the Police Department.