Households near roads will sigh sadly at this, car noise enthusiasts will hum: The Senate just passed (unanimously) a bill making it mandatory for all electric cars to emit some noise when operating.

The bill in question is the Pedestrian Safety Enhancement Act of 2010, backed by Sen. John Kerry, and it has but one purpose: “To direct the Secretary of Transportation to study and establish a motor vehicle safety standard that provides for a means of alerting blind and other pedestrians of motor vehicle operation.”

The problem, Kerry thinks, is that the imminent tidal wave of electric cars will bring death and destruction to the roads of America–borne on wings of silence. Because apart from road-on-tire noise, electric vehicles tend not to make much of a fuss as they move along at low speeds. There may be a distant whine from the motor, but it’s far from the throaty gurgle of a gasoline-based engine–for decades milk-delivery floats in the U.K. made the most of this benefit to get your early morning pint on your doorstep without waking you up.

But if you’re deaf, or, as many a dweller in big cities with hybrid cabs can attest, if you’re not religious in your “stop, look, listen” routine when you cross the road, then an EV could surprise you, resulting in injury or death. Hence the new law, which will require EVs of any design that requires running under solely electric power at low speeds to emit some sort of noise (at higher speeds, aerodynamic noise solves the problem). Given its unanimous vote, it’s likely to sail through the House when it gets there, and lead to further debate next year.

The matter is complex, despite the lobbying of the National Federation of the Blind, because not much science has yet been carried out in this area–this law is essentially being passed as a precaution, and it has one huge and unpleasant side effect: Road noise pollution. Many millions of people who live in dwellings near busy streets will have been looking forward to quieter, less-stressful lives as EVs take over from gas cars. Instead they’ll have to contend with a variety of hums, whirrs, and whines now–depending on what the Transport Secretary finds as acceptable noises and volumes. The NFB is reported to have been unhappy that drivers can turn off the noise on the Nissan Leaf, even though the noise is re-enabled automatically when you restart the car.