BBC crunches stats to try and establish whether urban or rural roads are more dangerous

An article on the BBC website has sought to determine whether city roads choked with traffic are more dangerous than those in the country. The article, by Michael Blastland in the BBC’s Go Figure series, employs statistics to try and find an answer to the question, using the roads of London and Northumberland to as examples of each type of location.

The latter is England’s most sparsely populated county, with an estimated average of 62 people per square kilometre, compared to 4,932 in London.

As the BBC says, one problem in trying to establish a definitive answer is that police forces do not collect specific data on how much traffic there was in the reports they compile on specific incidents.

Another is that some roads with few or no casualties on them may appear safe, but the figures may be misleading if, for example, they are avoided by vulnerable users such as cyclists and pedestrians, a theory outlined by John Adams in his 1995 book, Risk.

In absolute terms, there were 19 times more people killed or seriously injured (KSI) on Greater London’s roads in 2011 than there were in Northumberland; factor in billion miles driven, however, to arrive at a casualty rate, and that gap narrows dramatically, with the capital still ahead, but only by a factor of around one and a half.

But take into account time spent actually at the wheel, and Greater London’s lower average speeds see the casualty rate in Northumberland in 2010 run at getting on for one and a half times higher than that in Greater London.

Other variables – the class of road, type of road user, and the difference in official mortality rates from land traffic accidents – serve to cloud the picture too, although the suggestion remains that the effect of heavy, slow-moving traffic causes casualty rates to be lower than those in areas with lightly trafficked roads, with speed also likely to affect the severity of an incident.

As the BBC acknowledges, the comparison between the statistics is a “rough and ready” one, and Greater London and Northumberland were chosen arbitrarily as the areas to be examined.

What the article does show, however, is the effect of a variety of variables in trying to resolve the issue, plus the difficulty of ever managing to reach a decisive conclusion.

Moreover, as many of the people commenting on the article point out, it’s not necessarily roads themselves that are inherently dangerous – often, it’s the people using them.