•Cell phone conversations alone, without dialing or answering, change the way drivers see the world and make them more likely to miss traffic signs and other important information (see the special section papers by McPhee, Scialfa, Dennis, Ho, and Caird and by Atchley and Dressel).
•Using a speech recognition system to reduce distraction, such as speaking an address into a navigation system, can make the task easier, but it can still disrupt driving, particularly the driver's ability to control the vehicle's speed. Drivers slow down when entering information manually or by voice (see the paper by Tsimhoni, Smith, and Green).
•Information (such as telephone numbers) presented by voice competes for drivers’ attention to a far greater extent than when the driver sees the same information presented on a display. Horrey and Wickens found that auditory information led to poorer speed control than was the case with visual displays of the same information.
•The effect of distractions depends on when they occur. Interruptions to driving, such as answering a cell phone, are likely to be more dangerous if they occur during maneuvers like merging to exit a freeway (refer to the paper by Monk, Boehm-Davis, and Trafton).
