The voice-to-text features that car companies are offering to keep drivers’ eyes on the road may also be highly distracting, the U.S. consumer group AAA warned as it released the results of a two-year research project.

The new study, conducted by researchers at the University of Utah, found that voice-to-text software is roughly as distracting as talking on a handheld cell phone, which dozens of U.S. states have banned in an effort to keep drivers out of accidents.

The finding, coming as the National Highway Traffic Safety Administration prepares to craft distraction guidelines for cell phones and voice-to-text software in cars, suggests stricter rules could be on the way for hands-free devices and controls, which are not banned in any U.S. state.

“There is a looming public safety crisis ahead with the future proliferation of these in-vehicle technologies,” Robert Darbelnet, the president of AAA, said in a statement. “It’s time to consider limiting new and potentially dangerous mental distractions built into cars, particularly with the common public misperception that hands-free means risk-free.”

AAA wants limits

AAA, in releasing results of the study today, urged the auto industry and makers of portable electronics to consider limiting voice controls to key driving tasks, such as operating the air conditioning, windshield wipers and cruise control.

NHTSA has already proposed its first distraction guidelineswith the goal of making dashboard controls in cars less distracting. The guidelines, released in April, urge automakers to deactivate manual text messaging and Web browsing while a car is moving. But drivers are able to control an increasing number of these features with voice-to-text software.

The study undertaken by AAA, which counts 53 million members in North America, highlights a challenge facing car companies.

Automakers see keeping drivers connected as a way to add functionality, attract new customers, and win market share, but if features such as voice-to-text controls draw safety concerns from regulators and safety advocates, it could lead to a public backlash.

The Alliance of Automobile Manufacturers, which represents 12 automakers — including General Motors, Ford Motor Co. and Toyota Motor Corp. — said it cannot comment on the AAA study until experts at the group have a chance to review the study’s findings in detail. However, the group said that it sees the spread of hands-free controls as a positive development because the features keep drivers’ hands on the wheel and eyes on the road.

The Alliance has warned NHTSA that putting too many restrictions on technology built into cars could cause drivers to rely on their smartphones. The group said it is also worried about the public’s response to the AAA study.

“We are extremely concerned that it could send a misleading message since it suggests that hand-held and hands-free devices are equally risky,” a spokesman for the Alliance said in an e-mail response to Automotive News, a sister publication of Automotive News Europe.

“The AAA study focuses only on the cognitive aspects of using a device, and ignores the visual and manual aspects of hand-held versus integrated hands-free systems. There are many other acedemic studies under way, and road safety will be enhanced by letting the complete body of research drive policy recommendations.”

150 people studied

In the AAA study, University of Utah researchers found 150 people between the ages of 18 and 36, with an average age of 24 and an average of seven years of driving experience.

The participants wore brain sensors while driving a modified Subaru, and were asked to perform six tasks: changing the radio station, listening to a book-on-tape, having a conversation with a passenger, using a handheld cell phone, using a cell phone with a hands-free device, and sending an email with voice-to-text software.

Participants also had to drive while taking a standard test used by psychologists to measure brain function. The exam includes doing math problems and memorizing numbers.

While driving, the participants wore a headset. In the corner of their field of vision, protruding from the headset, a light would randomly turn red or green. When the light blinked a certain color, the driver was supposed to press a button on the steering wheel. Researchers measured how quickly they reacted.

While the driver was using voice-to-text software, they showed multiple signs of being distracted.

Response times were usually as slow as when drivers were using a handheld phone, and drivers also made fewer glances to check their surroundings. However, drivers did not show as many signs of distraction as they did while doing math problems as part of the standard psychology test.

David Strayer, the psychology professor at the University of Utah who led the research project, said that the study did not definitively show that voice-to-text features are unsafe. The researchers did not test how well the drivers were able to perform driving tasks, or how often they got into crashes.

Combating the arms race

But he said car companies seem to be engaged in an “arms race” to introduce voice-to-text features in light vehicles. The new study suggests that the hands-free voice controls come with risks, Strayer said, though some tasks, such as changing the radio station, may be safer than others.

“I’m not really convinced — and this is my own bias — that you need to be making Facebook posts driving down the interstate,” he said during an interview. “That could just be me being old-fashioned.”

The project was funded by the AAA Foundation, the nonprofit educational and research arm of the AAA. It cost about $250,000, AAA Foundation president Peter Kissinger said.

The next phase of the project will look at more specific types of voice-activated features, similar to Facebook and Twitter. Kissinger said the AAA Foundation will fund that research, too, and hopes to obtain results in early 2014.