In addition to being distracted and erratic, drivers using cell phones also slow traffic, a study confirms. Using a simulator with virtual traffic scenes, researchers discovered that drivers using mobile phones—even ones with hands-free devices—go more slowly on highways and pass sluggish drivers less frequently. "That SOB on the cell phone is slowing you down and making you late," one tells LiveScience.
In the experiment, drivers talking on cell phones were about 20% less likely to change into a faster-moving lane, drove an average of 2 mph slower, and took 15-19 seconds longer to complete a 9.2-mile freeway course. "The average person's commute is longer because of that person who is on the cell phone right in front of them," one researcher said.