That's a mod which replaces the horn of Dukes and some other cars.
Instalation:
1. You'll need Spark IV and GTA Ivaud.
2. Open GTA IV\pc\audio\sfx\resident.rpf with Spark IV.
3. Import the file HORNS.ivaud from the archive.
4. Press SAVE.
5. Play 'n' enjoy ;)

btw thanks to yodaag for helping :)