Although electric vehicles like the Chevrolet Volt are prized for their nearly silent operation, they have been deemed too quiet, and will need to have active pedestrian alert systems installed in coming years.

So says President Obama who on Jan. 4 signed into law S841, the Pedestrian Safety Enhancement Act of 2010 , after it was unanimously approved by the Senate.

Although details must be worked out, Public Law No: 111-373 will mandate EVs and hybrids sold in the U.S. to be equipped with some form of device or apparatus that will continually emit a certain minimum sound at lower vehicle speeds, and shut off automatically as speeds increase.

To protect pedestrians, bicyclists, and others considered vulnerable, EVs and hybrids
will eventually be required to emit some kind of always-on sound.

According to Jose Ucles, a spokesman for the National Highway Transportation Safety Administration (NHTSA) , definitive regulations could take four-and-a-half years before being imposed, more or less.

The next step is to initiate “rulemaking” over the following 18 months, Ucles said, and then a “final rule” will come within three years or so after that.

The process is not on a strict deadline, Ucles said. It has flexibility built in to allow for a proper study to further quantify the need for sound from EVs and hybrids, additional feedback to be given as required, and the results analyzed.

For the time being, Chevrolet Volts, which already come equipped with a warning system, will remain as they are.

“Nothing is going to change immediately,” said GM Spokesman Rob Peterson, until new rules are clear. “When it is required, we will obviously comply with that.”

Some background

Actually, voluntary compliance by some automakers is already causing issues. Both the Nissan LEAF and Hyundai Sonata Hybrid have stalled delivery to the UK and U.S. respectively, in anticipation of rules for these markets.

Citing the conflict, one EV-favoring editorial has already decried the increasing “absurdity” of the situation, as the question over just how dangerous silent cars might be is debated in regions around the world.

And sure enough, in a sense the shakeout could appear absurd as lawmakers in various countries come to differing conclusions about the threat, real or imagined.

To give a voice to those in the U.S. who say they have the most to gain or lose, we called the group most responsible for the new law, the National Federation of the Blind (NFB) .

“Yes, it was us,” said NFB Director of Public Relations, Chris Danielson of the initial move to get legislators and automakers to consider the needs of the advocacy group.

The ball got rolling in 2003, Danielson said, when blind people began noticing it was nearly impossible to hear when hybrids were passing or approaching at lower speeds.

Knowing they would be asking for a precedent, Danielson said they studied and debated the issues as well as they could for the first couple of years.

“We knew there would be concerns,” Danielson said, “that it might be controversial.”

At one point in their fact-finding journey, they invited alternative energy transportation industry stakeholders to offer their views. To that particular meeting, Danielson said, unfortunately few showed up.

Even when no one is near a rolling EV or hybrid, they will have to continually make precautionary sounds, at least at lower speeds. The U.S. DOT calls distracted driving an "epidemic," and concerns remain that drivers may not always be as vigilant as needed.

Further along the way, the NFB funded research that added weight to its argument.

“Dr. Lawrence Rosenblum, a perceptual psychologist at the University of California at Riverside, did conduct studies in which he asked subjects to listen to recordings of hybrid vehicles and press a button indicating which direction they thought the vehicle was approaching from,” Danielson said in a follow-up e-mail, “I believe that he also conducted experiments with an actual vehicle in a parking lot. He concluded that a pedestrian may have only a second between hearing a hybrid vehicle and being struck by it – not enough time to react and change course, in other words.”

Even people who can see have had near-miss experiences – including one lawmaker – who reportedly was almost run over by an unheard hybrid outside a grocery store.

In time, NHTSA also collected “statistically significant” data showing a higher incidence of hybrid/pedestrian collisions in states from which the information was available.

And beyond this, Danielson said anecdotal evidence has been adding up for years.

He recounted the story of one blind woman who had her foot run over, another person who was saved only by his guide dog, another whose white walking cane was crushed by a hybrid he could not hear.

“Until blind people start to get run over should nothing be done about it?” Danielson asked.

The NFB’s position is it likes quiet cars too, Danielson said, but essentially silent ones are asking for trouble.

The idea the NFB has since come to support, he said, is not only to protect the blind, but anyone who might be endangered.

This assertion has also been repeated by NHTSA.

Measures toward reconciliation

Obviously, along the way some people disagreed with mandating sound emitters, and proposed alternatives.

One suggestion was that the problem was not that cars were too quiet, but that suburban and urban environments are too loud.

Dodging the question of whether this could have been a case of the absurd fighting "absurdity," and regardless whether there's truth to it or not, in any case there is little chance of making an entire city quieter.

And even in quiet environments, Danielson said, problems can still happen.

Others have suggested implementing transponders to alert blind people.

Not only would he not want to have to carry an extra device at all times, Danielson said, it would do nothing to answer the critical question about a moving EV or hybrid answered best by hearing it: “How far away is it, which way is it traveling, and how fast?”

GM supports the concerns of the blind. You may have seen this video last November in an article about the Volt's warning system. Although GM tried, it appears remedies will be stronger still.

In the course of making its case known, the NFB gained support from the Alliance of Automobile Manufacturers and the Association of International Automobile Manufacturers.

Notwithstanding earlier non-participation, automakers have since been empathetic.

Initially, GM worked with the NFB, and designed the Volt’s warning system to alert pedestrians, and this was thought to be enough.

But the NFB – and the U.S. Congress and Senate – thought more needed to be done.

In 2008, H.R. 741 was introduced by Rep. Edolphus Towns (D-NY), and co-sponsored by 238 fellow members of Congress to propose making always-on sounds from otherwise silent cars mandatory.

It went no where.

In 2009, similar legislation sponsored by Sen. John Kerry (D-Mass.) with a total of 29 co-sponsors did make it through, was unanimously approved, and signed by the president.

Some additional details

The law does not apply to internal combustion engine vehicles, even if they are very quiet.

Exactly how much sound should be required from EVs and hybrids, what the tone should be, at what point it could be shut off, and related issues are to be studied.

Unknown is at what speed the car’s natural sounds from wind noise, rolling tires, etc. would be enough to be heard. It is expected pedestrian warning systems could be automatically switched off, say, at highway speeds, or speeds approaching them.

It is not specified whether the sounds come from a speaker, or some other device.

Whatever they come up with, it will be required to be tamper resistant.

Enforcement would likely be at the state level, so, for example, if an owner figured out how to deactivate the system, varying fines or penalties would be imposed state by state.

We do not know if a universal system would be mandated, or carmakers could come up with different solutions to satisfy a standard.

Also unknown is whether first-generation EVs and hybrids would be grandfathered in, or owners would be required to retroactively install pedestrian warning systems.

It is at least somewhat ironic that the law was passed and only now will formal studies be conducted to determine how much sound will be enough to make EVs and hybrids safer.