Cellphones May Not Cause Car Crashes, Show Study

    August 9, 2013
    Sean Patterson
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It’s now a given that talking on the phone while driving is dangerous. Public service announcements, ads from mobile providers, and laws in many states attest to that. However, a new study from researchers at Carnegie Mellon is now calling into question this supposed fact.

The study, published in the journal American Economic Journal: Economic Policy, shows that talking on a cellphone while driving does not increase the risk of a car crash. Researchers used data from a major mobile provider taken from 2002 to 2005, then cross-referenced it with accident reports from the same time period. Many mobile providers at that time offered free calling on weekends and at night, and call volumes seen by the research team reflected this. The car crash rates during these peak calling hours, however, did not see a subsequent increase.

“Using a cellphone while driving may be distracting, but it does not lead to higher crash risk in the setting we examined,” said Saurabh Bhargava, lead author of the study and an assistant professor of social and decision sciences in Carnegie Mellon. “While our findings may strike many as counterintuitive, our results are precise enough to statistically call into question the effects typically found in the academic literature. Our study differs from most prior work in that it leverages a naturally occurring experiment in a real-world context.”

The study also points out that laws banning the use of mobile phones while driving have also had no effect on vehicle crash rates.

The study’s authors emphasize that the research only pertains to talking on a phone while driving. It does not touch on texting, which they admit could be more dangerous. It also did not determine why the results were so different from previous studies, though Bhargava did put forth some hypotheses.

“One thought is that drivers may compensate for the distraction of cellphone use by selectively deciding when to make a call or consciously driving more carefully during a call,” said Bhargava. “This is one of a few explanations that could explain why laboratory studies have shown different results. The implications for policymakers considering bans depend on what is actually driving this lack of an effect. For example, if drivers do compensate for distraction, then penalizing cellphone use as a secondary rather than a primary offense could make sense. In the least, this study and others like it, suggest we should revisit the presumption that talking on a cellphone while driving is as dangerous as widely perceived.”

  • Vernon Balbert

    A couple of problems I see here. First, because the period of time of cell phone use involves those hours that cell phones have free minutes, traffic density is lower during those hours. The free minute periods are typically during the night time (7 PM until 7 AM, for example) and so the number of accidents are naturally going to be down due to lower traffic density. The second problem regards the laws about cell phone use. These laws typically say you can only use hands-free devices while driving while previous research has shown that hands-free devices do not reduce the number of accidents, so even if these laws are strictly obeyed, they still don’t solve the problem.

    In short, based on the article, the research is flawed and biased.