No evidence that California cellphone ban decreased accidents

July 16, 2014

July 17, 2014                                                            Daniel Kaffine

            Despite the widely held belief that using hand-held cellphones while driving is considered dangerous, in a recent study a CU-Boulder researcher found no evidence that a California ban on cellphone use while driving decreased the number of traffic accidents in the state.

            The findings are surprising, says Daniel Kaffine, an associate professor of economics at CU-Boulder and an author of the study.

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No evidence that California cellphone ban decreased accidents

July 17, 2014                                                            Daniel Kaffine

            Despite the widely held belief that using hand-held cellphones while driving is considered dangerous, in a recent study a CU-Boulder researcher found no evidence that a California ban on cellphone use while driving decreased the number of traffic accidents in the state.

            The findings are surprising, says Daniel Kaffine, an associate professor of economics at CU-Boulder and an author of the study.

CUT 1 “Our main result was that we found no evidence that the California cellphone ban decreased accidents, and this is surprising, because a lot of prior studies had shown that people who talk on cell phones, while driving, are just as impaired as people who are intoxicated. (:15) If it was as bad as drunk driving we would expect to see a large decline in accidents. (:52) And when we go to the data we just didn’t see any evidence that accidents actually declined in the six months after this ban that was put in place.” (:30)

            California enacted its ban on hand-held cellphones on July 1, 2008. For their study, Kaffine and his co-authors looked at the number of daily accidents in the six months leading up to the law being enacted and compared that to the number of accidents in the six months following the ban.

            He says they chose to look at a narrow window of time to reduce the number of variables that might have an impact on accident rates.

CUT 2 “The reason we kept the time window relatively short was to try to cut down on the number of things that could be changing over this time period. So, vehicles could be getting safer and that may affect accidents or the number of accidents that people get into. Certainly there was economic changes over this time period where you might expect the number of drivers on the road to decline a lot after the recession, for example. (21) There was a text ban that was put into place six months after the ban on hand-held cellphone use, and that was one of the major reasons for choosing that six-month window.” (:30)

            The study was not designed to determine why accidents did not decrease, but there are several possible reasons, says Kaffine.

CUT 3 “Certainly one possibility is that cell phone driving is less risky than some of these driving simulations had suggested. Other possibilities is that people stopped talking on their hand-held cell phones and started doing something equally distracting -- playing with the radio or perhaps using a hands-free device such as Bluetooth. It’s also possible that people simply didn’t comply with the ban.” (:23)

            Kaffine says one of the takeaways from this study is that simply passing a ban doesn’t necessarily mean it will have the desired effect that policy makers intended it to have.

CUT 4 “One of the punch lines, I think, for policy makers in how we might think about these results is that simply passing a ban on something doesn’t always get you the intended results. (:13) There are lots of reasons why the hypothetical effectiveness of the ban and the actual effectiveness of the ban may be quite different. And in this case, it looks like the actual effect of the ban was pretty minimal on making roads safer.” (:24).

 

            At any given moment during the daylight hours, over 800,000 vehicles in the U.S. are being driven by someone using a hand-held cell -phone, according to research by the National Highway Traffic Safety Administration.

            The findings of Keffine’s cellphone ban study are published in the journal Transportation Research Part A: Policy and Practice.

-CU-

 

 

 

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