Don’t blame the technology.
For those who argue that a ban on cellphone use while driving will make highways safer, there’s bad news: People who chat behind the wheel often drive more aggressively even after they hang up, according to a study from the Massachusetts Institute of Technology,
“The people who are more willing to frequently engage in cellphone use are higher-risk drivers, independent of the phone,” said Bryan Reimer, associate director of MIT’s New England University Transportation Center. “It’s not just a subtle difference with those willing to pick up the phone. This is a big difference.”
Reimer and a team of MIT researchers studied the behavior of 108 Greater Boston drivers. About half acknowledged frequent phone use when driving; the rest said they rarely used their phones behind the wheel.
And though none of the drivers used phones during the tests, the frequent callers tended to drive faster, change lanes more often, and spend more time in the far-left lane than those who rarely used their phones. The frequent callers were also more likely to accelerate rapidly and to slam on the brakes.
Nobody questions that it’s risky to use a phone while driving. The National Safety Council estimates that out of 5.4 million car crashes in the United States in 2010, 1.1 million — about 1 out of 5 — involved drivers who were talking on their phones at the time. Another 3 percent of crashes, or 160,000, involved drivers who were texting.
In response, many states have enacted laws to regulate use of cellphones by drivers. In 39 states, including Massachusetts, it is illegal to use text-messaging services while driving; 10 states ban voice calling unless the driver uses a hands-free system.
But even though driving while phoning can be dangerous, Reimer said, the research suggests the driver’s own personality may be the more significant risk. In other words, frequent calling while driving may be “an indicator of willingness to engage in risky behavior” in general, Reimer said.
The study raises the question of whether laws to ban cellphone use while driving will reduce road accidents. “Legislating the technology alone is not going to solve our problem,” Reimer said. “We need to look more at the behavior of the individual.”
Drivers would be better served with training to discourage cellphone use and to warn against other bad habits, he added.
Adrian Lund, president of the Insurance Institute for Highway Safety in Arlington, Va., said his organization has seen little benefit from restrictions on cellphone use. Lund said that so far, “we have not seen that those bans have reduced crashes.”
Lund added that the popularity of cellphones has not led to a spike in auto accidents. “When we look at crash-count data,” he said, “we don’t see crashes going up.”
Lund thinks the MIT study may help explain why accident levels have remained steady by showing that cellphone-using drivers are predisposed to risky behavior.
“Maybe if they’re not talking on their cellphones, they’ll be distracting themselves with something else,” he said.
The best way to reduce the risk is through better car safety systems, including collision warning systems, or sensors to detect when a car is straying from its lane, Lund said. Such systems, already available on some vehicles, can alert distracted drivers.
Massachusetts legislators are considering a ban on the use of cellphones while driving, unless the phone is equipped with a hands-free device to let drivers keep both hands on the steering wheel.
Despite the new study, State Senator Mark Montigny, a Democrat from New Bedford, said he will continue to support the bill.
“If the most irresponsible drivers are consistently irresponsible, fine,” Montigny said. “You can’t really legislate against irresponsibility or stupidity, but you can at least take away one of the distractions.”
Hiawatha Bray can be reached at firstname.lastname@example.org.