Search tips
Search criteria 


Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
JAMA. Author manuscript; available in PMC 2013 December 27.
Published in final edited form as:
PMCID: PMC3873766

Dangers of Distracted Driving

To the Editor: The Viewpoint on distracted driving by Drs Coben and Zhu1 missed the mark on the issues of potential effectiveness of legislation and benefits of hands-free phone interfaces. Coben and Zhu stated that “legislation that cannot be stringently enforced by law enforcement personnel is unlikely to be a deterrent.” Years of experience with traffic safety legislation has demonstrated that when people are allowed by law to engage in reckless behavior, many will. However, when a law is passed to stop unsafe behavior, many will stop, even without effective enforcement.

This was demonstrated in the case of seat belt laws and high-visibility enforcement.2 Impaired driving laws were initially difficult to enforce. However, after impaired driving legislation was passed, enforcement practices such as breath alcohol tests and the ability to obtain blood samples from suspected impaired drivers caught up with the laws. The same may happen with distracted driving laws, but without the laws first, enforcement practices will never be developed.

Coben and Zhu’s contention that distracted driving legislation should focus on handheld mobile device use while permitting hands-free interfaces is inconsistent with the research. Evidence suggests that hands-free phone use provides no safety benefit because it does not diminish cognitive distraction (ie, when the driver’s attention remains diverted from the task of driving).3 The World Health Organization, in discussing research about crashes resulting from mobile phone distraction, says: “It is this type of distraction— known as cognitive distraction—which appears to have the biggest impact on driving behaviour.”4

The study by Olson et al,5 cited by Coben and Zhu as support for safe hands-free phoning, did not measure cognitive distraction and had no method of determining hands-free cell phone usage by study participants. There are more than 30 studies examining hands-free phone use that have not been able to support a safety benefit.4 In December 2011, after numerous crash investigations involving cell phones, the National Transportation Safety Board called on states to pass legislation that prohibited all use of cell phones while driving, including hands-free use.

I support Coben and Zhu’s call for distracted driving legislation and stronger federal regulation, but legislation must address all forms of cell phone use, including hands-free systems and built-in systems that could be used by drivers to make or receive phone calls and texts, watch videos, or access the Internet.


In Reply: Mr Teater suggests that legislation, even without effective enforcement, will modify driver behavior and that enforcement practices will eventually catch up with the laws. Prior research has demonstrated that active enforcement is important to reduce unsafe driving behavior. Seat belt law experience has revealed that belt use increases shortly after the law implementation but decreases without active and sustained enforcement.1 Similarly, roadside observational studies have demonstrated either no change in driver handheld phone use following legislative bans2 or only transient effects that fade over the long-term without active enforcement. 3

Teater misrepresents our views about the potential use of hands-free devices. We did not suggest that hands-free devices provide a safety benefit. Rather, we reported that there is some evidence that hands-free phone interfaces do not pose an increased crash risk for drivers. There is an important difference between not posing an increased risk and providing a safety benefit. The naturalistic driving study cited in our article provides the most accurate measure of cell phone use, including hands-free use, immediately before the safety-critical event on the road.4 This study installed sensors and video cameras in fleet trucks, which are used for daily deliveries.4 The data represented 203 commercial motor vehicle drivers and 3 million miles of continuously collected kinematic and video data. The video data were examined to determine cell phone use and other factors, and the risk factors within 6 seconds of the safety-critical event were compared with those present during baseline driving. This study found that talking or listening to a hands-free phone did not increase the likelihood of a safety-critical event.

Nevertheless, as stated in our Viewpoint, we believe that additional research is needed to determine whether hands-free phone use poses an increased risk for drivers. The ongoing second Strategic Highway Research Program Naturalistic Driving Study will collect 3700 participant-years of continuous kinematic and video data from 2600 drivers of passenger vehicles. It will provide further evidence on whether hands-free cell phone use poses an increased risk for crashes.

We applaud legislative and regulatory efforts attempting to address the problem of distracted driving, and we encourage additional research to determine the risks imposed by various types of distractions. However, we renew our call for immediate action to specifically address the use of handheld phone devices. The technology currently exists to disable these devices while driving, and failure to implement this technology will result in continued public health and financial costs to society.

Jeffrey Coben, MD

Motao Zhu, MD, PhD

Author Affiliations: Injury Control Research Center, West Virginia University, Morgantown (jcoben/at/

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs Coben and Zhu reported receiving grants from the National Center for Injury Prevention and Control. Dr Coben also reported receiving support from the National Institute of General Medical Sciences. Dr Zhu also reported receiving support from the National Institute of Child Health and Human Development.

1. National Highway Traffic Safety Administration. Primary enforcement saves lives: the case for upgrading secondary safety belt laws. Accessed April 15, 2013.

2. Foss RD, Goodwin AH, McCartt AT, Hellinga LA. Short-term effects of a teenage driver cell phone restriction. Accid Anal Prev. 2009;41(3):419–424.

3. McCartt AT, Hellinga LA, Strouse LM, Farmer CM. Long-term effects of handheld cell phone laws on driver handheld cell phone use. Traffic Inj Prev. 2010; 11(2):133–141.

4. Olson RL, Hanowski RJ, Hickman JS, Bocanegra J. Driver distraction in commercial vehicle operations. Accessibility verified May 20, 2013.


Conflict of Interest Disclosures: The author has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.


1. Coben JH, Zhu M. Keeping an eye on distracted driving. JAMA. 2013;309(9):877–878. [PMC free article] [PubMed]
2. Campbell BJ. The association between enforcement and seat belt use. J Safety Res. 1988;19(4):159–163.
3. National Safety Council. [Accessed April 19, 2013];Understanding the distracted brain. 2012 Apr;
4. World Health Organization. [Accessed April 19, 2013];Mobile phone use: a growing problem of driver distraction.
5. Olson RL, Hanowski RJ, Hickman JS, Bocanegra J. [Accessed December 21, 2012];Driver distraction in commercial vehicle operations.