A new study by University of Utah psychologists finds that drivers who send and receive text messages drive more erratically and are six times more likely to crash than drivers who aren't texting.
Researchers found that drivers must "switch" all their attention away from the road when they are composing or reading text messages. Consequently, this activity is far riskier than talking to a passenger and 50 percent more risky than conversing on a cell phone, which past U. research has found also impairs driving ability.
"We show that mechanisms involved in texting and talking are very different in terms of attention. If someone is talking on the phone, they are dividing attention between talking and driving," said Frank Drews, an associate professor of psychology who is lead author in the study published in the current edition of the journal Human Factors . "In text messaging, it is an all-or-nothing process. If you are texting, you are not paying attention to driving. You are basically driving blind."
At least 19 states, including Utah, and many municipalities have banned texting behind the wheel, while none has completely banned talking on the phone.
Under the leadership of Drews and colleague David Strayer, a co-author on the new study, the U. has become a leading center for experiments on distracted driving. Strayer adapted a three-screen driving simulator to allow behavioral scientists to document reaction times, trailing distances and other driving behaviors in conjunction with nondriving tasks.
Distracted driving accounts for 6,000 fatalities a year, Drews said, and cell phones are the most common distraction in a growing array of on-board electronics, like entertainment and GPS systems and laptops.
Public-safety advocates say the U. experiments inform public policy discussions and help quantify the real costs of distracted driving.
"We can take this data, combine it with prevalence information and estimate how many crashes are caused by text messaging. Legislators need to know that stuff," said David Teater, senior director for transportation safety initiatives at the National Safety Council.
The federal National Highway Traffic Safety Administration uses street observations made in daylight and good weather to estimate the prevalence of cell phone use behind the wheel. These estimates cannot distinguish between those who are dialing a call, texting, or e-mailing, but they figure 11 percent of the driving public is using a cell phone at any given time. A small minority was seen manipulating the keys, leading observers to estimate that one in 100 motorists at this moment is jabbing phone buttons rather than looking at the road, Teater said.
The U. researchers selected 20 students, ages 19 to 23, to participate in the latest study as drivers, and 20 friends to engage in a texted conversation with the drivers as they piloted the simulator. Nearly all the participants, who used their own phones for the experiments, said they text while driving more than once a week.
"We wanted to mimic actual texting, which is something you do with someone you know," Drews said. "We gave them the task to coordinate evening activities. We wanted them to plan the evening using text messaging, something very typical."
Researchers found the texting drivers' reactions times slowed by 30 percent (versus nine percent for those talking on a phone). The distance from the car in front of them was more varied, they inadvertently changed lanes, and sometimes rammed cars in front of them. Six of the seven collisions that occurred during the study involved a texter.
While more states are banning texting while driving, Teaters suspects texting is "escalating at a dramatic rate," and not just among young drivers. Even the most well-meaning people find the message tone an irresistible cue to pick up the phone.
"We believe there is an addictive quality to this," he said. "It's almost a Pavlovian response."