Do hands-free devices make roads any safer?
However, as pointed out in my commentary (and also in a more detailed article about distracted driving on this site), there’s a scientific consensus that using hands-free devices is as dangerous as using hand-held phones while driving. Studies show the accident rates are the same for drivers whether they use hand-held phones or hands-free devices (Haque and Washington, 2014).
That’s because, as the psychological and cognitive science evidence show, the root cause of distracted driving is mental interference, not manual interference (Redelmeier and Tibshirani, 1997; Strayer and Johnson, 2001). Summarizing the research, I wrote:
it’s not physical interference from the phone but mental interference from the phone conversation that distracts from driving. Cellphones interfere with driving performance because they divert attention from one task (the driving) to another (the phone conversation). When phone conversations divert attention from driving, drivers are prone to causing car accidents.
Hence, my conclusion:
If lawmakers want to help solve the problem of distracted driving, a ban on cellphone use in the car—not just hand-held devices—is the only legislation that would work.
Overall, the article was well received, although plenty of public comments to my conclusion were polarized. Nonetheless, a common objection came to my attention.
Isn’t some legislation better than none?
In essence, the objection goes like this:
Isn’t some legislation, even if imperfect, better than none?
Taking that generic question at face value, I’d typically reply: Yes, even if some solutions aren’t ideal, we should adopt measures that nudge society toward incremental improvement. Having said that, I wouldn’t have criticized the hands-free law if it were an improvement. Unfortunately, I don’t believe it was.
Do hands-free devices actually reduce road accidents?
Here’s why. Thus far, a great deal of research shows that states with hands-free laws haven’t seen any significant reductions in car collisions or insurance claims.
One study, for instance, compared insurance claims for car collisions in D.C and three other states, both before and after hand-held phone bans went into effect. The results reveal either no significant reductions in claim rates or—perhaps surprisingly—increases in claim rates. In other words, car collisions do not appear to go down in states with bans on hand-held phones (Trempel et al., 2011).
If car collisions aren’t really decreasing in states with hand-held phone bans, it’s likely because these bans don’t help reduce car accidents. In short, they’re probably ineffective, because if drivers in states with those bans just switch to hands-free devices, their risk of being in a car crash remains the same (McCartt, et al., 2006).
To be sure, it’s fair nitpick some of the data and ask if researchers set up controls that properly isolate the variables in these studies. For instance, did researchers take into account changes in other laws affecting traffic and road safety?
However, further studies and statistical analyses that take those variables into account (Nikolaev, et al., 2010; McCartt, et al., 2014), as well as concomitant news reports (e.g., NPR and FiveThirtyEight), all point to the same conclusion: There’s simply no convincing evidence that bans on hand-held phones have any significant effect on road safety.
Don’t dial and drive—even with hands-free devices!
Clearly, the only policy that would help solve the problem of distracted driving would be not multitasking with cellphones in the car, period.
Obviously, we can take responsibility by turning our phones off in the car. Governments can help by passing laws banning the use of cellphones, including headsets, in the car. (Of course, we can make reasonable exceptions, such as emergency calls and GPS devices.) Tech companies could also play a role by engineering phones or developing apps that deactivate phones while users are behind the wheel.
In the meantime, the safest and most responsible thing everyone can do right now is not dial and drive. Really, you’re phone calls and texts will still be waiting for you when you get out of the car.
References
Haque, M.M. and Washington, S. (Jan 2013). A parametric duration model of the reaction times of drivers distracted by mobile phone conversations. Accident Analysis & Prevention, 62, 42-53. doi.org/10.1016/j.aap.2013.09.010
McCartt, A. T., Hellinga, L. A., and Bratiman, K. A. (Jun 2006). Cell phones and driving: review of research. Traffic Injury Prevention, 7 (2), 89–106. doi.org/10.1080/15389580600651103
McCartt, A. T., Kidd, D. G., and Teoh, E. R. (2014). Driver cellphone and texting bans in the United States: evidence of effectiveness. Annals of advances in automotive medicine. Association for the Advancement of Automotive Medicine. Annual Scientific Conference, 58, 99–114. www.ncbi.nlm.nih.gov/pmc/articles/PMC4001674/
Nikolaev, Alexander G., Robbins, Matthew J., and Jacobson, Sheldon H. (2010). Evaluating the impact of legislation prohibiting hand-held cell phone use while driving. Transportation Research Part A, 44, 182–193. http://shj.cs.illinois.edu/NRJ_TRA.pdf
Redelmeier, D. A. and Tibshirani, R. J. (1997). Association between cellular-telephone calls and motor vehicle collisions. New England Journal of Medicine, 336, 453-458. doi.org/10.1056/NEJM199702133360701
Strayer, David L. and Johnston, William A. (2001). Driven to Distraction: Dual-Task Studies of Simulated Driving and Conversing on a Cellular Telephone. Psychological Science, 12 (6), 462-466. doi.org/10.1111/1467-9280.00386
Trempel R.E., Kyrychenko, S.Y., and Moore, M.J. (2011). Does Banning Hand-held Cell Phone Use while Driving Reduce Collisions? Chance, 34, 6–11. www.iihs.org/topics/distracted-driving
I’ve you’ve any ideas for ways to reduce distracted driving, I’d love to hear them. Feel free to leave a comment below, or check out other Educational Topics on this site.
Christopher: I both dis&agree with you.
The cognitive load of just talking with someone who cannot see the surround and thus understand the varying cognitive loads of talking is immense.
This presumes that the distant conversant does not know when conversation should pause, and thus asks: “Are you still there?” Anticipating this makes many of us prioritize the conversation higher than driving. Not good.
Managing interaction with the keyboard is another matter, whether to text, to “dial” a call, or to access GPS information. I believe this is far more distracting than conversation, though I do not have data to prove it.
Minnesota’s law requires that phone use in transit be “one touch.”
I can use Siri to access any call or text after this one touch, for most processes. Even so, I seek out the relative shadow of a tractor/trailer before such a “one touch” event. I think the current law has some clear benefit, if it changes behavior to within its strict limits. Do not hold the phone. [This limits temptation to text.] I am not happy about an exception to access GPS navigation. I will be very interested to follow enforcement of the “one touch” provisions of this law. Bruce Parker
Thanks for sharing. Enjoyed reading this.
Someone shared your article on LinkedIn after I commented on his post.
My comments to him:
Love that article. We know some distraction is good, some more acceptable, and then we do not understand at what level do things go crazy (not that science can determine the acceptable level as that is a policy decision).
My original comments on his post that started “Using a cell phone while driving is irresponsible and flat out dangerous” are below:
We need to determine how much distraction/risk is acceptable; we also need to figure out how fatalities did not rise as usage of edevices just exploded. With those two caveats, I agree: drop the phone.