Cell Phones Dangerous After You Hang Up

TESTING TESTING TESTING TESTING Researchers have found scientific evidence that driving while talking on your cell phone significantly reduces alertness and may pose a serious risk in traffic.

Researchers from Carnegie Mellon and the University of Rhode Island measured drivers' alertness while conducting cognitive tasks, like talking on a cell phone or remembering lists.

"There is a very substantial decrease in the amount of brain activity, the amount of neural activity allocated to driving, while you are simultaneously listening," said Marcel Just, a Carnegie Mellon professor.

Just's study used magnetic resonance imaging to measure subjects' brain activity while using a cell phone. According to the study, the amount of brain activity decreased 29 percent when participants were listening to a conversation.

"The fundamental implication is that engaging in a demanding conversation could jeopardize judgment and reaction time if an atypical or unusual driving situation arose," said Just.

It’s All in the Eyes

URI's Manbir Sodhi and Jerry Cohen designed a head-mounted, eye-tracking device that measures the position of a driver's eye. The device has two cameras: one that looks at the road and one that can measure 250 eye movements per second.

According to Sodhi, drivers' eyes move constantly when focused on the task at hand — driving — but when engaged in other cognitive tasks while driving, like changing a radio station or talking on a cell phone, those eye movements slow significantly. During cell phone conversations, the eyes stayed focused straight ahead and drivers experienced tunnel vision.

"You are not moving [your eyes] as much … You are keeping them straight ahead more than you would under quite normal conditions," Sodhi said.

And Sodhi found that the so-called tunnel vision does not end when the conversation does, perhaps because drivers are still thinking about their conversation.

Even the cell phone industry acknowledges the dangers of driving on the phone and promotes safe habits.

"It's real simple when you get behind a wheel of a car," said Tom Wheeler, president of the Cellular Telecommunications and Internet Association. "Your first, second and third priority is to drive safely."

Problem Isn’t About Holding the Phone

New technologies, like hands-free tools, have attempted to reduce the danger of dialing or dropping the phone while driving. But testing has shown that it doesn't matter whether you use a handheld or hands-free phone. The problem comes with the concentration needed for the conversation itself.

"The issue isn't about holding the phone or not holding it. It is one about being involved in an intense task while being involved in another intense task," Sodhi said.

Just said, "It's really that the brain can only do so much at one time. … In a demanding traffic situation, to have a complicated conversation, is just taking a chance."

But despite concerns, both men don't advocate a handheld cell phone ban, like that imposed on New York drivers. Instead, they advocate cell-phone-free zones, where drivers would be prohibited from using their phones in areas with heavy traffic or areas that requires a driver's full attention.

Just said imposing a total ban "seems a bit draconian to me."

"If you're out in the middle of the plains and there's no cars in sight, why not chat on the on the phone?"