Drivers who use hands-free cellphones to talk or send messages are two times more distracted than those who don't, and using hands-free devices that translate speech into text is the most distracting of all, according to researchers. Speech-to-text systems in new cars that enable drivers to send email and text messages required greater concentration by drivers than other potentially distracting activities examined in the study like talking on the phone, talking to a passenger or listening to the radio.
Researchers found that drivers using speech-to-text technology are three times more distracted. They say it tends to cause mental blocks like "tunnel vision."
"People are actually not seeing what's going on on the side of the road. They're not seeing the person standing at the crosswalk waiting to cross or the stop sign," said AAA senior researcher Dr. Steven Bloch. "The other is what's called inattention blindness where even things that happen right in front of them they're losing track of. They're not following properly."
AAA officials who briefed automakers, safety advocates and the National Highway Traffic Safety Administration on the study's findings said they want devices installed in cars that would actually limit the use of voice activated technology to basic activities like turning on the air conditioner and windshield wipers. The National Safety Council, responding to the AAA study, also called on industry and policymakers "to reconsider the inclusion of communications and entertainment technology built into vehicles which allow, or even encourage, the driver to engage in these activities at the expense of focusing on driving."
The Alliance of Automobile Manufacturers was skeptical. "We are extremely concerned that it could send a misleading message, since it suggests that hand-held and hands-free devices are equally risky," the association said in a statement.
Other studies have also compared hand-held and hands-free phone use, finding they are equally risky or nearly so. But a recent NHTSA study of drivers' real world driving experiences found hand-held phone use was less safe than hands-free.
Researchers at the University of Utah conducted the present study for AAA. They used high-tech devices that measured drivers' brain activity while they were not driving, while driving in a simulator and while driving a car through a Salt Lake City neighborhood.
The Associated Press contributed to this report.