Using voice-to-text messaging, included in systems such as Ford Motor Co.'s Sync and Toyota Motor Corp.'s Entune, is more distracting to drivers than making calls with handheld mobile phones, a study by AAA found.
Texting a friend verbally while behind the wheel caused a "large" amount of mental distraction compared with "moderate/significant" for holding a phone conversation or talking with a passenger and "small" when listening to music or an audio book, the AAA Foundation for Traffic Safety found in a report released Wednesday.
Automakers have promoted voice-based messaging as a safer alternative to taking hands off the wheel to place a call and talk on a handheld phone. About 9 million infotainment systems will be shipped this year in cars sold worldwide, with that number projected to rise to more than 62 million by 2018, according to a March report by London-based ABI Research.
"As we push towards these hands-free systems, we may be solving one problem while creating another," said Joel Cooper, a University of Utah assistant research professor who worked on the study. "Tread lightly. There's a lot of rush to develop these systems." The findings from the largest U.S. motorist group bolster National Transportation Safety Board Chairman Deborah Hersman's call to ban all phone conversations behind the wheel, even with hands-free devices.
Outgoing Transportation Secretary Ray LaHood has asked drivers to put their phones in the glove box while driving and declined to criticize systems like Sync and Entune, which allow drivers to speak their commands.
The study used drivers, mostly in their 20s and 30s, to do things including listening to a radio and talking on a handheld phone.
Participants, all of whom had good driving records, did the tasks first in a lab, then in a driving simulator and finally in a residential area while driving. Researchers measured reaction time and brainwave activity with caps secured to drivers' heads to see what was the most distracting.
For the on-the-road portion, participants drove a Subaru Outback outfitted with cameras, computers and a researcher in the back seat to measure their responses. The vehicle had a Samsung Electronics Co. Ltd. phone with a hands-free device rather than an in-vehicle system.
Researchers controlled a possible variable, without telling participants, by having the person receiving the messages do the text conversion manually. The intent was to eliminate any faults in voice recognition software so the degree of distraction wasn't exaggerated by the driver having to make corrections.
Florida last month became the 41st U.S. state to ban handheld texting while driving. States, which set and enforce driving laws rather than the federal government, haven't addressed distraction caused by voice controls, nor have U.S. regulators asked them to. The NTSB recommends safety changes while having no regulatory power.
LaHood's department, in non-binding guidelines issued April 23, asked automakers to bar Internet browsing and the use of social-media sites such as Twitter Inc. and Facebook Inc. through in-vehicle infotainment systems when a vehicle is moving.
Automakers were also urged to design navigation and other screen-based systems so that drivers don't need to take their eyes off the road for more than two seconds to select an option, or for a total of 12 seconds to complete an entire task such as entering an address.
Jacob Nelson, AAA's director of traffic safety advocacy and research, said the guidelines don't address the distraction of taking one's mind off driving.
"We would be hopeful that moving forward, you will hear very different responses out of DOT," Nelson said.
The AAA study follows a Transportation Department-funded study, released in April, that found hands-free texting distracted drivers as much as messaging with a handheld device.
Participants in the study by the Texas A&M Transportation Institute drove on a closed course while typing text messages with their hands and sending them hands-free using Apple Inc.'s Siri and Vlingo system on Google Inc.'s Android phones.
Both methods slowed driver reaction times almost two times what they'd be when not texting, the study found, with drivers taking longer to complete a text when speaking than when manually typing.
Automakers have said that limiting in-vehicle infotainment systems, some of which allow drivers to buy movie tickets and make a dinner reservation, would lead drivers back to using handheld devices.
AAA is asking automakers and electronics suppliers to work with it on the next phase of research to parse the first study's voice-to-text technology findings and assess distractions of voice-command systems, said Peter Kissinger, chief executive officer of the AAA foundation.