Remember that the bulk of car noise (at least at higher speeds) is not related to the engine at all, but is just the tires rolling on the street surface. At re

Remember that the bulk of car noise (at least at higher speeds) is not related to the engine at all, but is just the tires rolling on the street surface. At residential speeds, there does appear to be the need for some sort of audible cue that a car is moving for the safety of nonmotorists.