General Motors will announce Wednesday that it's working with one of the largest advocacy organizations for the vision-impaired to find ways for the next-generation electric cars to make enough noise that pedestrians can hear them coming.

GM says it's working with the National Federation of the Blind on technology to make sure that near-silent electric cars and hybrids don't sneak up on unsuspecting walkers or runners.

It's potentially a growing problem as the nation switches to battery-powered cars as an alternative to high-priced gasoline. A bill that would direct the Transportation Department to regulate a solution the Pedestrian Safety Enhancement Act was introduced in Congress earlier this year.

One study already points to dangers. Walkers and bicyclists are being struck at a greater rate by hybrid vehicles than by conventional cars, concluded the National Highway Traffic Safety Administration in September.

"I've had probably 25 blind people in the country tell me they've almost been hit by these cars," says NFB President Marc Maurer. Vehicles brushed up against some or crushed their white canes, he says.

Maurer says he believes electric cars of the future will need to be equipped with a forward-directed sound device that operates without interruption while the car is in motion. All electric vehicles will have to make roughly the same artificial noise, he says, so that blind people will be able to distinguish them as moving vehicles.

Automakers balk at going that far for the moment. Toyota, the largest producer of hybrid cars, says it is still studying the issue. So is Nissan, which plans to introduce the all-electric Leaf next year.