A new study concludes that drivers talking on cell phones are probably making everyone’s commute longer, according to the Associated Press. The study, based on three dozen students driving in simulators, found that drivers on cell phones are far more likely to stick behind a slow car in front of them and change lanes about 20 percent less often than drivers not on the phone. Overall, cell phone drivers took about 3 percent longer to drive the same highly traffic-clogged route (and about 2 percent longer to drive a medium congested route) than people who were not on the phone. Distracted drivers are adding an extra 5 to 10 percent of time to your commute, says study author David Strayer, a psychology professor at the University of Utah. If you commute by car an hour a day, it could all add around 20 hours a year to your commute, he says. It's simply a matter of brain overload. Your frontal cortex can handle only so many tasks at one time, so you slow down, Strayer says. The AP reports that Strayer’s earlier studies have found slower reaction times from drivers on the phones and compared those reaction times to people legally drunk.