When is car noise pollution and when is it a necessity? Well at either end of the extremes it seems. Anyone living near a major auto route must be praying for the day still somewhat distant when we all drive around in near silent electric cars but there are those for whom the small but growing number of hybrid and all electric cars represent a real threat. I speak of the blind, of cyclists, joggers listening to music and the simply inattentive pedestrian. According to a study by America’s National Highway Traffic Safety Administration last year appearing in a Telegraph article, hybrids were twice as likely to be involved in a pedestrian crash than conventional cars when slowing, stopping, backing up, or entering or leaving a parking space.
Sarah Simpson in Scientific American reports that in experiments led by perceptual psychologist Lawrence D. Rosenblum of the University of California, blindfolded subjects who listened to recordings of cars approaching at 5 mph could locate the familiar hum of a Honda Accord’s internal-combustion engine 36 feet away. But they failed to identify a Prius, running in electric mode, until it came within 11 feetâ€affording them less than two seconds to react before the vehicle reached their position. And that was in the absence of traffic noise or other distractions. When a level of background traffic noise was added in the Accord was audible from 22ft away whereas the Prius got them every time.
As sales rise, Toyota sold nearly 270,000 units of the Prius in the first half of this year, a 117% increase over a year ago, the problem will become more acute particularly when the vehicle is in all electric mode. The new Nissan Leaf is set to go on sale in the US and Japan later this year and early interest suggests sales may rise rapidly. Other manufacturers such as GM with the Volt are not far behind. As a result, Toyota is bringing out a $150 dealer fitted after sale add on termed an “on-board approaching vehicle audible system in Japan following new government guidelines there earlier this year. New Prius models will be offered with a built in speaker mounted under the bonnet which will emit an engine like sound said to rise and fall with the speed of the vehicle up to about 20 mph. Above that speed, tire and wind noise are said to make electric cars clearly audible.
Nissan will also be offering the Leaf with a speaker cited behind the left headlight that emits a “turbine sound which is said (heaven forbid) to sound like an airplane taking off (we seriously hope this description is a mistake).
A bill before Congress is set to mandate the Transportation Department to establish safety standards for hybrids and other vehicles that make little discernible noise, including an audible alert.
It does make you wonder though how do deaf people avoid being run over on busy streets or when cycling on bikes? Could it be they just look? May be this is a life skill we all have to learn in a quieter, all electric world?
–Stuart Burns
