Developers of the upcoming Ford Focus electric vehicle are having to think of ways to make a quiet vehicle noisy, rather than the other way around, and are turning to the auto maker’s Facebook friends for suggestions.

“Traditionally, our objective has always been to make (a vehicle) as quiet as we can for the occupants,” Eric Keuhn, chief engineer for global electrified programs, tells Ward’s. “This is contrary to that.”

The challenge he refers to is developing an artificial sound to alert pedestrians, primarily the elderly or those who are blind, of an approaching vehicle that otherwise is silent.

In an effort to garner feedback and promote discussion on the topic, Ford has created a link on its electric-vehicle Facebook page here that features four sample sounds.

Keuhn says engineers are not looking for the public to pick the sound that will be used, “but for feedback, whether good, bad or indifferent.”

The issue of EVs having to emit a noise is being addressed by both auto makers and government regulators. The “Pedestrian Safety Enhancement Act of 2010” was signed by President Obama Jan. 4.

The act gives the U.S. Secretary of Transportation two years to “determine the best means to provide the blind and other pedestrians with information about the location, motion, speed and direction of vehicles,” authors, Reps. Ed Towns (D-NY) and Cliff Stearns (R-FL), say in a statement.

The rule-making process currently is under way, with auto makers and advocacy groups, including those serving the blind, submitting ideas that will be used to forge the final legislation. Keuhn expects the law to be in place by 2014, about three years after the launch of the Focus EV, due later this year.

Despite the absence of a formal law at launch, he says the Focus EV will debut with a sound that will be emitted by an external speaker system.

“What will happen is each auto maker will have in place what they deem necessary to support the intent (of the law),” he says, noting a decision on how many speakers will be used or where they will be placed has not been determined.

Feedback from Facebook so far has garnered “blended” results as to what people prefer, Keuhn says, and none of the four sounds posted have proven more popular than the others.

Some of the comments on the website are practical: “As long as it's not much louder than a regular gas car (which are super quiet these days), I’m fine with it,” one friend says.

Others suggestions are humorous: “How about the sound George Jetson’s car makes?” And one person suggests letting owners select their own sound, an idea that Keuhn and his team are considering. “But the (final) rule-making may not allow it.”

The four sounds on Facebook are just a sampling of the dozens being tested by Ford.

“We have some technology sounds and some that are almost like interrupting sounds, where you get a certain background (noise) like a motor, but it fades in and out of another sound,” Keuhn says.

Decibel levels also are being determined, with careful consideration not to cause unnecessary noise pollution, a concern EVs are supposed to help alleviate.

Because the sound will be used to warn pedestrians of an EV’s presence, it likely will be emitted only at low speeds, about 25 mph (40 km) or less.

“We’re presently in the process of defining not only the sound level for what we want but also at what speed,” Keuhn says. “Once the final rule making is done, we may have to make (vehicle) adjustments.”

bpope@wardsauto.com