By Robert Sumwalt
A few days ago someone told me he liked to use his driving time to catch up on returning phone calls. Without trying to sound like too much of a zealot, I told him the NTSB has called for states to pass laws prohibiting non-emergency use of wireless communications devices while driving. Then came the answer I have heard too many times – “Oh, I use a hands-free device.”
Somewhere along the way, drivers have started believing that talking on cell phones using hands-free devices is safer than using hand-held devices. Sorry to break the news, but the notion that hands-free is safer is — quite simply — a myth. Many sources, including the makers of after-market hands-free devices and lawmakers who pass laws only outlawing hand-held devices, would like for you to believe one is safer than the other. The overwhelming data, however, show there is no significant difference in crash risk between hand-held and hands-free devices.
The National Safety Council, for example, has compiled more than 30 research studies and reports by scientists around the world that show hands-free phones offer no safety benefit when driving. The paper describes how drivers who use cell phones have a tendency to “look at” but not “see” up to 50 percent of the information in their driving environment. A form of inattention blindness occurs, which results in drivers having difficulty monitoring their surroundings, seeking and identifying potential hazards, and responding to unexpected situations.
The under-appreciated risk here is the cognitive distraction associated with talking on a phone while driving. A study by AAA Foundation found that a driver’s level of cognitive distraction is about equal when using either hands-free or hand-held cell phones. Quite simply, because we are so busy concentrating on the phone conversation, our brain can’t process other information. Hard to believe, right? Well, perhaps you’ve experienced a situation where you missed a turn, ran a red light, or failed to stop at a stop sign while talking on a phone. NTSB has seen more extreme examples that led to serious consequences. For example, a few years ago we investigated an accident where the top of a bus carrying high school students was sheared off because the driver drove under a bridge with inadequate clearance. The driver was involved in a heated conversation with his sister using a hands-free phone. Investigators asked if he noticed the signs before the bridge that indicated that the bridge was too low for his vehicle. He not only missed seeing the signs, but he did not even notice the bridge until after he sheared off the top of the bus, injuring several students!
A question often asked is how does talking on phones differ from talking to a passenger in the vehicle. As we all know, in many cases, passengers in the car can be distracting – especially when the passengers are young children or rowdy teens. However, in the case of a licensed driver as a passenger, studies show they will often adjust their conversation when they notice the driver is facing a potentially challenging driving situation such as merging or complex intersections. This may lower the risk of distraction, although any conversation, whether on a cell phone or with a passenger in the vehicle, has the potential to be distracting.
While hands-free devices allow a driver to keep hands on the wheel and eyes on the road, use of these devices overlooks the disruptive effects of not being able to keep your mind on the driving task. The best way to minimize risks associated with wireless communications devices is to not use them at all while driving. After all, no call is so important that it can’t wait.
Robert L. Sumwalt was sworn in as the 37th Member of the National Transportation Safety Board on August 21, 2006. He is a frequent contributor to the NTSB blog.