Road Safety News

Study finds no link between mobile calls and crashes

Tuesday 13th August 2013

Researchers in the US claim to have found no link between drivers making phone calls while driving and the crash rate (BBC News).

A team from Carnegie Mellon University and the London School of Economics analysed data before and after 9pm local time over a three-year period. The timeslot was chosen because during the period studied (2002 - 2005) many American mobile phone operators offered free calls after 9pm.

The study found that while there was an increase in callers using multiple phone masts after 9pm, there was no corresponding increase in the number of road incidents. The results, however, do not include text messaging or internet browsing.

Admitting the researchers were "very surprised" by the results, professor Saurabh Bhargava from Carnegie Mellon University, said: “At first we thought the numbers were wrong. We went back and checked everything - but there was nothing going on at all. We just saw a big jump in cellphone use and there was no impact on the crash rate."

Dr Vikram Pathania from the London School of Economics said that the findings, published in the American Economic Journal, came with a number of caveats.

Dr Pathania said: "We were only looking at talking, not texting or internet use. And it may be that the traffic conditions on the road at that time are such that moderate use of cellphones does not present a hazard."

Dr Pathania suggested that further research should focus on smartphone use, and also overall phone use among different driver demographics, adding that “it may look different if you focus on young males or new drivers.”

Click here to read the full BBC News report.


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The '100 car naturalistic study', also conducted in the US using instrumented vehicles, is probably one of the best examples of a real-world study into driver behaviour. Use of a 'wireless device' was found to be the most common form of inattention resulting in crashes, near-crashes or 'incidents'. I've attached a link to a summary report for anyone interested.
Matt Staton, Cambridgeshire

Agree (9) | Disagree (0)

I notice that using a phone whilst driving is not an offence in all US states so possibly the risk is perceived to be much lower in the more sparsely populated regions perhaps. Also, their road widths and layouts could be considered to be more forgiving of driver errors. Doesn't make the study's method any more vaild however.
Hugh Jones, Cheshire

Agree (4) | Disagree (3)

For those who want a "scientific" study, those involving a simulator are the closest we will get. The observational study probably did not get a result as the collision rate is low and the time that people are on the phone is low and the times that they are distracted at critical times are low so the population wide change will be low and therefore not show up when using this method which (passengers etc) are creating statistical noise. For an individual using the phone all the above lows become highs and the effect on them and others is significant if not life changing.
Mark Caerphilly

Agree (4) | Disagree (3)

There seems to be no link that I can see between the movement indicated by use of multiple phone masts and whether or not the phone was that of a driver or a passenger in a vehicle, train, or bus, so how valid is it?
Michael, Edinburgh

Agree (4) | Disagree (3)

I find it hard to believe that this 'study' attracted funding to carry it out. I suspect that the money for it may have come from a mobile phone company. It does not take an expensive studies by expert scientists to conclude that humans do not perform two separate tasks particularly well when asked to do them simultaneously. When one of these tasks is driving, which the majority of the public can not do well in the first place, safety is envitably compromised when a phone call is made.
David, Suffolk

Agree (12) | Disagree (3)

The evidence of one's own eyes is sometimes the best evidence and is actually real-world evidence. This applies to other driving offences and faults as well - stats don't always paint a true picture.
Hugh Jones, Cheshire

Agree (10) | Disagree (6)

Hugh, you could do that but you'd have to follow thousands of drivers and take notes of numbers, incidents and mileages. And then you'd have to do the same for thousands of motorists not on their phones as well to compare.

Given that isn't practical then the best evidence we have are your colleague's accident investigations compared with surveys of phone usage. They show no accident increase for drivers on mobile phones whatsoever. Look them up and you will be surprised.

The above report is consistent with accident investigations and surveys of phone usage and there is no real world evidence that contradicts, as far as I know.
Dave Finney, Slough

Agree (7) | Disagree (8)

Dave: How's this for a scientific trial... follow a driver on his/her 'phone and see how long it is before there's a near miss, or worse. In the meantime, observe how their adherence to other traffic laws and good driving practice goes out of the window. Much better evidence than the 'study' referred to in the article.
Hugh Jones, Cheshire

Agree (13) | Disagree (5)

The results of the report, which takes a novel and far more accurate approach than the simulator tests many rely on, should not be surprising to anyone who has looked at the evidence. The percentage of collisions involving drivers on mobile phones is way lower than the percentage of drivers on mobile phones. IOW, if you stand on a road picked at random, those drivers on the phone are less likely to crash than those not on the phone.

Strange I know, and counter to what we all believe safe driving is about, but this poses a question that is at the heart of road safety. Do we want road safety policies to be dictated by the best evidence, or by the opinions of those in authority?

If the former, we need a complete rethink of all road safety policies including how to measure the effect of interventions. In particular, we need to start using scientific trials where possible.
Dave Finney, Slough

Agree (6) | Disagree (10)

Hugh, yes you are correct the multiple phone masts does imply a moving phone. That could be simply walking, passenger on a bus or in a car and, yes, it could be the driver. The claim seems flawed from what we see reported here.
Allan, Leicester

Agree (6) | Disagree (4)

Bob: My first reaction was like yours i.e. "How do they know anyone was travelling at all?" but I notice they refer to callers using 'multiple 'phone masts' and whilst I'm no expert on this technology, I presume this must indicate a 'moving' signal.
Hugh Jones, Cheshire

Agree (12) | Disagree (0)

I would think that it would be obvious that those who were using free phone calls on mobiles would not be out driving at that time of the night. One of the quietest times during the day. Sit in, relax, chill out, a good film, popcorn and call all your mates doing the same thing. There is no evidence there that anyone was driving and using a phone at all.
bob craven

Agree (11) | Disagree (4)

It seems a bit naive to try and prove (or not) a link using this method, leading to a rather tenuous conclusion. How do they know for instance, whether the callers were actually at the wheel at the time and not simply passengers?
Hugh Jones, Cheshire

Agree (20) | Disagree (4)