Study Indicates That Driving While On Phone Is Not As Dangerous As Thought

For almost 20 years, it has been a wide-held belief that talking on a cellphone while driving is dangerous and leads to more accidents. However, new research from Carnegie Mellon University and the London School of Economics and Political Science suggests that talking on a cellphone while driving does not increase crash risk.

Published in the American Economic Journal: Economic Policy, the study uses data from a major cellphone provider and accident reports to contradict previous findings that connected cellphone use to increased crash risk. Such findings include the influential 1997 paper in the New England Journal of Medicine, which concluded that cellphone use by drivers increased crash risk by a factor of 4.3 - effectively equating its danger to that of illicit levels of alcohol. The findings also raise doubts about the traditional cost-benefit analyses used by states that have, or are, implementing cellphone-driving bans as a way to promote safety.

"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, assistant professor of social and decision sciences in CMU's Dietrich College of Humanities and Social Sciences. "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."

For the study, Bhargava and the London School of Economics and Political Science's Vikram S. Pathania examined calling and crash data from 2002 to 2005, a period when most cellphone carriers offered pricing plans with free calls on weekdays after 9 p.m. Identifying drivers as those whose cellphone calls were routed through multiple cellular towers, they first showed that drivers increased call volume by more than 7 percent at 9 p.m. They then compared the relative crash rate before and after 9 p.m. using data on approximately 8 million crashes across nine states and all fatal crashes across the nation. They found that the increased cellphone use by drivers at 9 p.m. had no corresponding effect on crash rates.

Additionally, the researchers analyzed the effects of legislation banning cellphone use, enacted in several states, and similarly found that the legislation had no effect on the crash rate.

"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. 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."

Pathania, a fellow in the London School of Economics Managerial Economics and Strategy group, added a cautionary note. "Our study focused solely on talking on one's cellphone. We did not, for example, analyze the effects of texting or Internet browsing, which has become much more popular in recent years. It is certainly possible that these activities pose a real hazard."

LexSucks - 8/15/2013 11:04:53 AM

-1 Boost

Maybe no accidents but a major annoyance. Some folks slow down and drive 5 miles below the speed limit to talk on their phone. Reason they do that is because at that point they are being a lot less attentive to the task of driving then if they weren't talking on a cell phone.

The article states that; "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,"

- Yeah they slow down to 5 miles per hour. How's that being more cautious? The article is complete bollocks.

cidflekken - 8/15/2013 11:14:32 AM

+1 Boost

A couple of things that aren't clarified:
- how did they know the calls were made using the handset vs. bluetooth ear piece or bluetooth connection in the car. Granted, from 2002-2005, bluetooth wasn't as prevelant, but ear pieces did exist and I know as early as 2003, I believe, some states had already banned the usage of cell phones while driving.
- how is it confirmed that it was, in fact, the driver making the call and not a passenger
- what were the actual crash rates as a ratio of number of drivers to crashes? Basically, the number of crashes didn't necessarily increase after 9p according to their study, but if there were fewer drivers on the road, which would likely be the case after 9p, then the true "rate of crashes" is much higher

Sciros - 8/15/2013 12:12:09 PM

+1 Boost

There are lots of factors that are hard to account for. If you compare using proportions that is a good start (say the % of drivers using cell phones goes up while the % of drivers in accidents goes down, regardless of the total number of drivers before and after the time in question). However, the number of drivers on the road may have an impact on the frequency of accidents, and there are fewer of them at night than at, say, rush hour. But then again, speeding, drunk driving, and driving without a safety belt all increase at night, based on other reports. Plus the reduced visibility in the dark may have a measurable impact.

The point is there are complex factors at play here that make it difficult to isolate and evaluate a single one stand-alone. But my opinion is that we should therefore be quite cautious about criminalization.

TheSteve - 8/15/2013 11:42:28 AM

+3 Boost

Study finds most studies to be grossly inaccurate and flawed, yet many people continue to form their opinions based upon them.

LJ745 - 8/15/2013 6:18:32 PM

+1 Boost

The problem here is that after 9pm, you have fewer vehicles on the road. So you could say, just look at crashes as a percentage of people on the road. However, that is to assume that the crash rate varies linearly with traffic density. This is probably not true, though I have no stats on the issue. My guess would be that the relationship is very complicated, with certain densities being worse than others. The study did not make clear either if these were single or multi-car accidents. I would be more inclined to believe the findings if the rate of single car accidents remained unchanged.

The next finding, that legislation has no effect would be fine if the study was not drawing the conclusion that cell phone use is not dangerous. Legislation may have no effect because people generally disobey it. Having given no numbers on compliance, all we can conclude is that legislation is ineffective, not that cell phone use while driving is not dangerous.

I'm not a fan of nanny states and legsilation, butthis is a very poorly designed study and thus is of no use in drawing conclusions.