You know I was going to jump up and down shouting I told you so … except I cannot find the post from ages ago where I pointed out that this might be a problem (extra points to anyone who finds the link!). The BBC has just had a story about the dangers to visually impaired people from “quiet cars” – hybrids and electric vehicles. Actually of course it is just about everyone who finds it helpful to hear cars coming – indeed I will listen to my iPod on “mono” in certain situations to ensure I get an early warning from the noise of approaching vehicles.
Whilst loud vehicles are an enormous pain and I certainly would not want to encourage their use. The person who invented car stereos loud enough to cause nearby buildings to shake – and yes they can get that loud – needs to be tied down and forced to listen to my choice of music for a few weeks. So called silent cars do also cause problems; in fact a certain amount of noise results from the tyres running along the road. We are used to relying on sound to assist us in locating moving vehicles; in some cases it is the only sense we can rely on.
Apparently Lotus engineers have come up with a nifty system that generates noise that varies according to the amount acceleration the driver is applying. Sorry guys, you’ve been sniffing petrol fumes too much. Whilst the driver may be impressed by the feedback he (or she) gets when they press the acceleration pedal, the rest of us are more interested in the speed of the vehicle. Sound effects for the driver are all very well (when played inside the car) but rather out of scope for this discussion.
It would not be difficult to make hybrid and electric cars generate a noise when they are moving nearly silently. And the most sensible thing to do is to standardise the noise generation before we end up with a confusing variety of different sounds and volumes. The simplest is to have a tone generated when a vehicle is moving that starts low in pitch at low speeds and rises in pitch as the speed increases. Think old-fashioned milk floats.