There is some good discussion of synthetic car noises in Norman's "Design of everyday things". Sound is a hard to use interface that could still offer great usability advances if we work out to harness it properly.
I see people asking "why not rely on the horn to alert pedestrians". The horn is the equivalent of shouting "oi" but engine sound is hugely rich source of information. We get: speed, direction, distance, acceleration, attitude (e.g. distinguish aggressive acceleration, panicked deceleration) and type of car (e.g. racer vs. town-car).
Unlike a horn, we get this information at the times a horn would not be used i.e. the driver has not seen us and about to mow us down. Synthetic car noise must alert, orient but not annoy. Norman said the current United States National Highway Traffic Safety Administration spec for synthetic car noise is 250 pages long.
I see people asking "why not rely on the horn to alert pedestrians". The horn is the equivalent of shouting "oi" but engine sound is hugely rich source of information. We get: speed, direction, distance, acceleration, attitude (e.g. distinguish aggressive acceleration, panicked deceleration) and type of car (e.g. racer vs. town-car).
Unlike a horn, we get this information at the times a horn would not be used i.e. the driver has not seen us and about to mow us down. Synthetic car noise must alert, orient but not annoy. Norman said the current United States National Highway Traffic Safety Administration spec for synthetic car noise is 250 pages long.