Talking on a hands-free phone may be more distracting than talking to a passenger riding in the car. (ISTOCKPHOTO)

Makers of cars and mobile electronics are pushing a tempting vision of the future, one in which you can stay fully connected while driving. In the name of safety, they provide hands-free wireless setups for your cellphone, so you can talk with both hands on the wheel. The latest additions are voice-to-text systems that let drivers send and receive texts and e-mails without looking at a screen. Some high-end cars even have touch screens with interfaces for finding restaurants, reserving tables and buying movie tickets while on the road.

Has all this made the impulse to stay connected while driving any safer? According to a new study, definitely not.

The study, conducted by University of Utah psychologist David Strayer and sponsored by the AAA Foundation for Traffic Safety, compared driver response in different situations. Listening to the radio or audiobooks was judged mildly distracting. Talking on a hand-held or hands-free phone or to a passenger was more distracting, with hand-held conversations the worst of these. But voice-
activated systems to send and receive texts and e-mail were the worst kind of distraction.

The fundamental problem is that safe driving demands attention, but multitasking divides our mental resources. “Just because a new technology does not take the eyes off the road does not make it safe to be used while the vehicle is in motion,” Strayer wrote in the study.

His data show that talking to the voice-to-text system is more cognitively demanding than talking to a person, leaving less brainpower for driving.

The National Highway Traffic Safety Administration says distracted drivers killed more than 3,300 people in the United States in 2011. In April, the agency recommended that manual text entry and the display of text messages or Web content be blocked in all moving vehicles.

A previous study by Strayer found that talking on a hands-free phone was more distracting than talking to a passenger riding in the car. In 2002, a British Transport Research Laboratory study found that drivers talking on hands-free sets reacted more slowly to events than drivers who were just over the drunk-driving limit. (Driving simulators were used in that study, not actual vehicles.) And in 2005, Australian researchers found that drivers using both hands-free and hand-held cellphones were four times as likely to crash as those not on the phone.

Safety rules in many countries have fallen far behind the research, which has confirmed the obvious dangers of drivers’ taking their eyes off the road to text on a hand-held phone. In the United States, a series of accidents has helped push 41 states to ban texting while driving. Six other states ban only younger drivers from texting. Only 11 states have banned drivers from talking on hand-held phones. There are no bans on hands-free talking or texting by using Bluetooth or other connections.

“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,” says AAA President Robert Darbelnet. The group wants to limit voice controls to “core” tasks such as operating windshield wipers and climate control, and to disable voice-to-text systems when moving.

Hecht is a regular contributor to New Scientist magazine, from which this article was excerpted.