Cellphone Use May Not Increase Accident Risk
August 9, 2013

Study Claims Cellphone Use By Drivers Does Not Increase Accident Risk

redOrbit Staff & Wire Reports - Your Universe Online

Laws attempting to prevent distracted driving by prohibiting people from using cellphones while operating a motor vehicle do not reduce crash risk, researchers from Carnegie Mellon University (CMU) and the London School of Economics and Political Science claim in a new study.

The researchers, who have published their findings in the American Economic Journal: Economic Policy, analyzed data from a major cellphone provider and accident reports and found no link between mobile device use and increased crash risk.

Their findings contradict previous research, including a 1997 New England Journal of Medicine study which concluded that cellphone use by drivers increased crash risk by a factor of 4.3 – making it effectively equal to the risk-rate increase associated with illegally operating a vehicle while under the influence of alcohol.

“Using a cellphone while driving may be distracting, but it does not lead to higher crash risk in the setting we examined,” Saurabh Bhargava, assistant professor of social and decision sciences in CMU's Dietrich College of Humanities and Social Sciences, said in a statement. “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.”

Bhargava and his colleagues also said that their research casts doubts about the traditional cost-benefit analyses often used by states looking to prohibit cellphone use by drivers as a safe-driving initiative, and that this type of legislation had no discernible impact on the crash rate in states that had passed such measures.

As part of the study, the researchers looked at phone and crash data from 2002 to 2005 – a time frame chosen because many mobile service providers offered free calling on weekday nights after 9pm during this period. For the purposes of their study, the researchers said that they identified drivers as those whose cellphone calls had been routed through multiple cellular towers.

The statistics showed that drivers made an average of nearly eight percent more calls starting at 9pm. Armed with that knowledge, the study authors compared relative crash rate both before and after 9pm utilizing data on roughly eight million crashes across nine states, as well as all fatal crashes occurring nationally during the three-year window. They found that increased phone use by drivers in the night had no corresponding effect on crash rates.

“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,” Bhargava said. “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,” he added. “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.”

Of course, co-author Dr. Vikram S. Pathania of the London School of Economics Managerial Economics and Strategy group emphasizes that the research applies to phone calls made using mobile devices only. Their research did not study the potential hazards associated with texting or Web browsing while operating a motor vehicle.

Not everyone agrees with Bhargava’s and Pathania’s conclusions, however. Talking on a cell phone was believed to have been a factor in a recent train wreck in Spain that killed 79 people, according to the US National Safety Council. In a statement earlier this week, the NSC said, “We know using a cell phone while operating a vehicle is risky,” and that “the human brain is incapable of simultaneously processing two cognitively demanding tasks, such as talking with someone on a cell phone while operating a vehicle. This cognitive distraction increases a driver’s crash risk fourfold and is the reason hands-free devices do not offer a safety benefit.”

Likewise, in announcing a new global safe driving campaign on Monday, Randy L. Ortiz, CEO and President of vehicle theft recovery firm LoJack called distracted driving “a nationwide epidemic… Almost daily we learn of another tragic death caused by distracted driving.” He added that “we all need to do more to address this tremendous challenge” and emphasized the importance of “understanding of the dangers of distracted and unsafe driving behavior.”