Statistics on road accidents in Great Britain are published by the Department for Transport (DfT) and are available broken down by Parliamentary constituency. In this blog post, we look at the constituencies with the most and least accidents and consider the factors which might make a constituency particularly high- or low-risk with regard to road casualties.

The data show that areas with high total numbers of accidents do not necessarily have the highest numbers of fatalities, and vice versa. Although UK roads are very safe compared with other countries, there is still room for further improvement – both in terms of reducing the overall number of accidents, and reducing the seriousness of accidents that do happen.

How are accidents measured?

All official road accident statistics are based upon accidents reported to police as involving personal injury. The number of fatalities is thought to be robust and the number of serious accidents reasonably reliable. However, there is likely to be an undercounting of slight accidents, as some incidents involving only property damage or very minor injuries may not be reported to police.

Road accidents are single, somewhat random events – so looking at single year’s worth of data, particularly in relatively small areas such as constituencies, may give a misleading impression. For this reason, 6 years of data (2010 – 2015) are aggregated for the analysis below.

Where do fatal accidents happen?

Constituencies with the highest number of fatal accidents tend to be those with larger geographic areas (i.e. rural constituencies), but within populated regions, leading to a significant amount of through traffic. Areas without motorways appear to be a factor as well, as motorways are among the safest type of roads in the country. Only two constituencies out of the top 10 for fatal accidents have motorways running through them.

Constituencies with the most fatal accidents, 2010 – 2015

Constituencies with the lowest number of fatal accidents tend to be those in urban areas, but outside major city centres. These are areas where high volumes of traffic and large numbers of vulnerable road users (cyclists / pedestrians) mean that the number of fatalities is likely to be higher.

Because of the somewhat random distribution of road accidents discussed above, it’s not possible to state with any certainty that the constituencies on the above list are systematically less likely to have fatal accidents than those with slightly higher numbers. Lots of constituencies have very few fatal accidents: 55 have had fewer than 1 fatal accident per year over the period in question.

Total accidents: inner cities fare worst

In terms of the total number of personal injury accidents, the story is very different to merely looking at the most serious accidents.

The 10 constituencies with the highest total number of accidents are all inner city constituencies, with 7 being in or near central London. The Cities of London and Westminster constituency has more than twice the number of accidents of any other constituency – this is in part due to its location in Central London, but also due to its relatively large size compared to other city centre constituencies. A larger size within an urban area means that there are more roads and more junctions at which accidents could potentially take place.

The 7 London constituencies on the list above cover roughly 0.03% of the total land area of Great Britain, but account for almost one in twenty personal injury accidents.

The preponderance of personal accidents in inner cities is very likely due to the high number of road users on a limited amount of road space, together with a high number of vulnerable road users (cyclists and pedestrians). Relatively minor, low-speed collisions between cars are less likely to result in personal injury, and hence appear in these statistics, while almost any accident involving a pedestrian or cyclist is liable to result in injury.

With the exception of the two Scottish island constituencies, those with the fewest accidents tend to be urban areas away from city centres, where traffic pressures are less severe and there are fewer vulnerable road users.

All data sourced from Deportment for Transport Table RAS10016.

Picture credit: Mt Pleasant Rd by FraserElliot Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY 2.0)