
Using cell phones while driving causes “inattention blindness,” whereby the driver looks directly at the road but doesn’t really see. More often, conducting a conversation via a cell phone demands greater continuous concentration that diverts the driver’s eyes from the road and his/her mind from driving. An earlier study by the same university found that motorists who talked on hands-free cell phones were 18 percent slower in braking and took 17 percent longer to regain the speed they lost when they braked.