A new study conducted at the University of Utah and published in the journal Human Factors (subscription required) reveals some interesting points of comparison between those who use mobile phones while driving and drivers impaired by alcohol.
The study used 40 subjects, each of whom was tested under four different sets of conditions: undistracted, hand-held mobile phone, hands-free mobile phone, and intoxicated to a blood-alcohol level of 0.08 percent (a common legal threshold in many states). Participants were placed in driving simulators and asked to follow a pace car around a specified course.
Three accidents occurred during the testing, all of which involved cell phone users rear-ending the pace car. Phone users were also slow to brake, displaying reaction times 9 percent lower than unimpaired drivers, and slow to accelerate, with a 19 percent decrease in returning to speed after braking. This is viewed by the researchers as especially significant, since it has implications regarding traffic flow in high-density areas. In contrast, alcohol-impaired drivers tended to drive more slowly, yet more aggressively than other drivers.
Contrary to the opinions of lawmakers who have legislated against the use of hand-held phones while driving, little distinction was noted between drivers no matter what style of phone they were using. That suggests that it is the conversation itself—as opposed to the device—which is responsible for the distraction. This seems to jibe with the results of a study released in February, which tracked drivers’ habits over a period of months, and found that conversing with fellow passengers in automobiles is just as distracting as using a cell phone.
Both intoxicated drivers and those with mobile phones shared the common trait of believing themselves to be unimpaired while behind the wheel. Additionally, cell phone users and intoxicated drivers tended to be less perceptive of changes in their environment. This result was almost certainly anticipated in the case of alcohol users, since the effects of that substance have been well-studied. It would be instructive to see how mobile phone users fare on a future version of the ape test.
Frank Drews, an assistant professor who worked on the project, suggests legislators may wish to consider outlawing cell-phone use in automobiles. He may be jumping the gun: a small study using 40 subjects and which appears to lack a double-blind environment can hardly be considered definitive. Although one might find reason to take issue with the exact degree of the study’s results, it looks like it has been proven once again that driving distracted is a bad idea. Perhaps the most important aspect to come out of the Utah study is an apparent lack of distinction between using different types of phones from a distraction point-of-view. As a cell-phone-using driver myself, I’d certainly hate to see the devices outlawed completely.