American Truck Simulator will get a lot of custom sounds especially for prefabs. Depending on where you are, custom sounds will be played in the background. Also it will depend whether it is day or night which sounds will be played. Check the video below posted by SCS today to convince yourself.
Also we have reasons to believe that American Truck Simulator release date is very close to us as SCS said in their latest post that they are working on the ‘finishing touches’.