Kato, I thought that for cars it is 81db as per Road Traffic (Vehicle Standards) Regulations 1977
Adi
* edit * seems like that reg was repealed. The proper one is 90db - ROAD TRAFFIC (VEHICLE STANDARDS) RULES 2002 - REG 144
http://www.austlii.com/au/legis/wa/c...2308/s144.html