Damien Grant: On-road texting risks yet to be studied

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If you ignore the cellphone ban when you drive yet worry about the risks, I have good news.

Research done in 1997 and published in the New England Journal of Medicine claimed that mobile phone-use increases the accident risk four-fold. It was based on post-incident analysis of 699 Toronto crashes and was an influential study that led to bans on cellphone use. It has since been shown to be defective.

First, it was conducted in 1997 when cellphone ownership was not ubiquitous.

Further analysis has shown early-adopters of cellphone technology (the young and adventurous) are more likely to get into trouble. Second, the study failed to account for factors such as boredom or stress, which can cause drivers to pick up their phone but may actually be the underlying factor leading to a mishap.

Third, and most damning, the data was sufficiently imprecise that it failed to distinguish between calls made immediately before and after the crash, rendering it void.

Facts, however, will not deter us from our prejudices. It seems obvious that using a cellphone would increase the risk of an accident and, helpfully for busy-body bureaucrats the world over, further studies confirmed this. A series of laboratory-style studies measured the responsiveness of drivers engaged in phone conversations and concluded their reaction times were slower.

In an insightful piece of research in the American Economic Journal last month, two economists looked at data from California over an 11-day period in 2005. At the time, there was a 9pm pricing change, making calls after that time much cheaper. The researchers were able to identify vehicle-based cellphone use (calls that rapidly changed between towers) and confirm that the 9pm change drove a use spike. The researchers compared the timing of road incidents from 1995, when there was no 9pm tariff change and fewer cellphones, to 2005. If mobile phone use makes you a bad driver then research would show a relative spike in crashes after 9pm. There wasn't. Using a mobile phone made no difference to the level of vehicle accidents. Our Ministry of Transport identified 25 road deaths between 2003 and 2008 in which mobile phones were believed to be contributing factors. There were 2,121 road deaths in that time; so about 1 per cent of accidents involved a cellphone, presumably equal to the amount of time people spent driving and talking.

Road fatalities peaked in 1987, when mobile phones existed only in Maxwell Smart's shoe and we had a million fewer cars.

The authors of the study caution texting and browsing were not part of the analysis.