From July 1, drivers in California will be in trouble with the law if they chat or conduct business with one hand on the steering wheel and the other clasping a cell phone to the ear. They won’t be in trouble if they are using headsets, speakers or other hands-free devices. New York, New Jersey, Connecticut, Washington state and Washington DC have enacted similar laws. Is the new law an empty gesture? In so many words, California Gov. Arnold Schwarzenegger says “no.” Recent research suggests otherwise.
The governor says the new law will reduce accidents. "Getting people’s hands off their phones and onto their steering wheels will save lives and make California’s roads safer," he explained in a Los Angeles Times report on the new law in June.
But hands are not the issue, according to the research. A study published in 2006 in Human Factors: The Journal of the Human Factors and Ergonomics Society reported that drivers talking on cell phones are as impaired as drivers with the 0.08 percent blood alcohol level that defines drunken driving in most states. Researchers led by Professor David Strayer, Principal Investigator at the Applied Cognition Laboratory at the University of Utah (UU), and Frank Drews, assistant professor of psychology at the university, also found that hands-free cell phones are no less dangerous while driving than hand-held cell phones.
In a July 2007 interview with The Ergonomics Report™, Professor Drews explained that the study was designed “in such a way to give us a direct comparison with an activity where society decided that the risks were associated with it were too high that we couldn’t tolerate it.”
A progression of studies leading to the alcohol test started when the two professors saw the results of a 1997 study by another team. It evaluated the cell phone records of 699 people involved in road accidents and found one-fourth had used their phone in the 10 minutes before the crash. It was a four-fold increase in accidents compared with undistracted motorists. The team speculated there was a comparable risk from drunken driving and cell phone use while driving.
The UU team also found in experiments using driving simulators that people can become so involved in conversation that they fail to see objects on the road, a condition called “inattention blindness.” And these drivers were found to be blind to their impairment.
The Ergonomics Report™ article cited a 2005 Australian study, published in the British Medical Journal, for which researchers interviewed 456 hospitalized cellphone users who had each been involved in a crash. The scientists combed the drivers’ call records to see how cellphone use affected their driving. Whether they talked hands-free or with a phone clasped to their ear, the result was the same: during calls, and for 10 minutes after their completion, a driver’s likelihood of crashing shot up fourfold.
Reporting on the impending California ban, Britain’s Economist magazine cited a recent Swedish study that found motorists’ reaction times increased disproportionately when they were talking on the phone—regardless of whether they are using a handheld or hands-free phone. The only thing that counted was the complexity of the conversation.
And you don’t have to be the one doing all the talking for your reaction times to lengthen dangerously. According to scientists at Carnegie Mellon University in a study published in April in the journal Brain Research, subjects who were allowed to navigate undisturbed showed robust activity in the brain’s parietal lobe. The region is associated with spatial sense, distance calculations and judgments that require a person to calculate his whereabouts in a broader physical environment. The study found that merely listening can reduce activity in the region of the brain that processes spatial and visual information by as much as 37 percent.
Professor Drews said he is encouraged by the convergence of evidence about risk in a number of studies, regardless of whether they are simulations or actual roadway tests. “Most people find odds ratios that are around 4 to 5, that is, the increase in risk of getting into an accident if you talk on a cell phone.” The convergence of evidence contradicts any claim that the finding is a fluke, he said.
Predictably, the cell phone industry has been quick to dismiss the studies. According to Professor Drews, the industry argues that by emphasizing cell phones the researchers are trivializing all other distractions. In its ranking of distractions, the industry asserts that the odds ratio is higher for eating a hamburger than talking on a cell phone, and concludes eating a hamburger is much more dangerous.
The professor agrees with the assessment, but sees a flaw in the argument. “At any given time during the day in the United States 10 percent of the driving population is conversing on cell phones. I think this is not true of eating hamburgers, or putting on makeup or shaving, so we are talking about a very, very high level of exposure (with cell phones.)”
Sources: Ergonomics Report; Los Angeles Times; Economist