For some, electric vehicles are too quiet, and consideration is already being given to requiring EVs to be more audible. Eventually, the outcome from the Pedestrian Safety Enhancement Act of 2010 is likely to require that electric vehicles make some sound, at least at low speeds, to help provide an auditory signal to pedestrians, cyclists, and others in order to improve safety. Even sighted people rely on audible cues to know that a vehicle is nearby.
In my recent test drive of the forthcoming Volkswagen E-Golf, I immediately noticed that this car makes noise. The purr made by the E-Golf is a variable tone (that sounds like a "young Wookiee" according to Autoblog Green). It is characteristic and distinctive, and seems to relate to engines and motors while not being a usual engine sound.
I had this car roll up behind me as another test driver came back from their loop in the car, and I would likely not have been aware of the car's presence without the sound. In general, I think it is effective, and not annoying or intrusive. It communicates its presence and it changes with the speed of the vehicle, which is something that happens naturally with a conventional engine, as well.
But, when driving this car, I found my perception of the sound was as something external, rather than part of the car I was driving. At one point, as I was about to pull out onto the road, I heard the sound increase, and I momentarily hesitated, because the sound seemed to be from outside, as though another vehicle was coming, rather than the sound seeming to be related to teh car I was driving. Almost immediately, I realized what it was, and that the road was clear, and I continued on. But the sound was behaving differently enough that it gave me that brief pause.
This was only an intial impression, and I only spent 10 minutes or so in the car. Very likely, a regular driver of one of these cars will become accustomed to the sound and how it relates to the car. I don't think I would have any problem acclimating to it if I was driving this car regularly. But to me, it is indicative that the development of sound for EVs may have subtleties that will need to be worked out in order to find the right way to provide sound cues from electric cars.
[Ed. Note: Volkswagen paid for the travel and lodging for my trip to SF where I gathered some of the information for this story.]
image credit: Volkswagen