A sound truck is a vehicle equipped with a public address system and loudspeakers, typically used to play recorded messages at high volume to the public while driving through residential areas. They are used in many countries by groups to disseminate political messages, such as by candidates during election campaigns, and in some countries for commercial advertising and promotion. They are also used by public safety authorities during emergencies, such as evacuations, to get information quickly to local populations. The use of sound trucks for advertising is illegal in many jurisdictions. It is legal in Portugal and usually used during election campaigns by political parties. It is also legal in Japan. For the legal situation in the United States see Saia v. New York (1948) and Kovacs v. Cooper (1949). In Bagé, Rio Grande do Sul, Brazil, the level of the sound cannot exceed 65 decibels.
Sound truck, operated by the Communist Party of Japan, seen in Aichi, Japan
Political campaign sound truck belonging to 1940 Florida, USA gubernatorial candidate Hans Walker.
German police sound truck
loudspeaker truck in Poznan, German-occupied Poland, 1939
Experimental horn loudspeaker truck, Los Angeles, California, 1929. It used an "artificial larynx" powered by compressed air and rented for $300/hr.
- ^ Melissa Louçan (2011-10-11). "Prefeitura atua na fiscalização de carros de som no centro da cidade". Minuano Online (in Portuguese). Retrieved 2011-12-23.