If you use air horn it's illegal
Air Horn, uses a compressor to pump air into horn to generate
sound.
Most people think this one air horn:
it's actually not and it's legal. Yes its louder, but since the
tone is lower it has shorter reach.. On highway at speeds you horn
vehicle, the vehicle in front sometimes don't realise which
direction the horn coming from.
I prefer snail type horn for use in city area, where speed is
low and vehicle close together.
Loudest electric automotive horn so far IMO is this:
Hella SuperTone 139db, it's about 50% bigger then normal stock
horn. Has further reach then snail horn type. Can view stock horn
and Supertone sound comparison video: http://youtu.be/3XLULsqTIpA
Stock vs Supertone size comparison:
Most
air horn or snail type horn rated at 110db - 118db, so supertone
easily louder
This one also popular, Stebel Nautilus :
But since it uses a compressor to generate the sound it is
clasified under air horn so illegal in singapore.
Best is if can install snail horn and supertone and make a
switch, so on hoghway use supertone, in city area use snail
type.
Oh yah, all the horn above last time i tried before but not on a
taxi.. For road legal lah, for taxi different thing cos the cab
don't belong to you. So if cab catch fire, even if the horn did not
cause it, cab company might say u change horn that's why fire
started...
