For the past while, I've been seeing reports on TV and in the newspapers about the danger of hybrid vehicles being too quiet when running on battery power at low speeds. This isn't something new, but as more hybrids take to the roads, pedestrians are worrying about their safety. The Japan Times reported on it last month:
One of the virtues of owning a hybrid or electric car is its super-quiet noise signature. But worries are growing that blind people are being endangered by the vehicles' silence.
The government has set up a panel involving automakers, consumer groups and organizations for the blind to find a solution, which could lead to the emission of virtual engine noise or sounds similar to cell phone ring tones, officials said.
A legal change would be needed to equip the vehicles with the special noise-making feature.
As for the panel, documents from the their initial meeting suggest that it's not clear a serious problem even exists. One document [PDF] points out that automakers have received 60 inquiries about the quietness of hybrids over the past 4 years. A sampling of the comments suggests the silence of the cars is more of an annoyance than an danger with comments ranging from someone being startled by a hybrid silently creeping up next to them to the hope that hybrids get some other device beside their horn to alert pedestrians.
The danger from quiet hybrids sounds overblown. First, it's not clear that a problem exists. Is the Prius really that quiet or it is the high ambient noise level that makes the car difficult to hear? Lord knows Japan's cities have a terrible noise pollution problem. It's also not clear how mandating that hybrids make a fake engine noise or emit a chime increases safety when regular "noisy" cars aren't any less prone to running over people. Are the horns hybrids are equipped with not good enough to warn people? Is this really a problem with the car or with pedestrians and drivers failing to pay attention to their surroundings or drive with care?
Apart from their fuel economy, hybrid vehicles are an opportunity to reduce the noise pollution that surrounds us all day. The silence of hybrids should be a plus, not a problem. The transport ministry forgets that part of what makes the experience of pedestrian zones (hokosha tengoku) and other public places inviting and pleasurable is their absence of vehicles and the din of traffic. Rather than trying to find a way for pedestrians and cars to co-exist, perhaps the transport ministry should think about separating the two instead of applying a techno band-aid.
The fake engine noise requirement doesn't bode well for electric vehicles if and when they are mass produced. Will they have to make noise as well? The answer, at least in the U.S., seems to be, yes. Cue "car tones."