One of the more satisfying sounds is the 290 fuel squeezer Cummins engine with exhaust turbo whining in a cabover sleeper Freightliner, with all 18 wheels whining harmoniously on the freeway asphalt at 0200 in the morning. Spotting a drowsy driver wavering ahead, possibly drunk but probably just falling fatally asleep, you maneuver to his six o'clock and blip the VERY LOUD thud of Jacob's compressor brake switch,(illegal in most small hamlets) restoring said malfeasant to instant wakefulness and a blip into the next rest area. A life possibly saved, you and the strawberries head on to the Big Apple... The air horn would work too but the Jacob's is just cooler.