The Rate of Diesel Car Ownership across Great Britain

Over the past six months, there has been growing levels of attention placed on diesel cars, due in part to the social narrative surrounding air quality levels and the increasing awareness concerning the real world emissions of local pollutants from diesel car operation. Research conducted by a variety of different organisations has demonstrated that a gap is present between the level of emissions measured by the official tests (such as the New European Driving Cycle) and those observed on the road for diesel cars (the International Council on Clean Transportation is a good source of information). This situation has generated calls for action from the government, which is viewed as being partly responsible for the widespread use of diesel cars due to a circulation tax policy which seemingly favoured the registration of diesel cars.

The figure above displays the proportion of new car registrations in Great Britain by fuel type between 2001 and 2015 (source: Department for Transport – Vehicle Statistics). There has been a convergence during this time period, going from an 80-20 split between petrol and diesel to a parity in registrations, which has persisted for the past five years. However, as air quality is a local problem, looking at national statistics only provides a partial understanding of the situation. We’re now capable of understanding the structure of local car fleets that are registered across the local authorities of Great Britain, which provides intelligence regarding where diesel cars have integrated to a higher or lower degree.

The map above reports the proportion of local authority car fleets that are diesel fuelled as of 2016.  A large range is apparent in this statistics, with Eden in Cumbria representing the local authority with the highest level of diesel registrations at 51.22% whereas the London borough of Sutton is the local authority with the lowest level at 24.27%. The proportion of diesel fuelled vehicles also appears to be strongly linked to the level of rurality, with areas of the England & Wales that are more sparsely populated tending to have high rates of diesel ownership. Interestingly, urban areas that have prominent air quality problems (such as Greater London) seem also to have amongst the lowest rates of diesel car ownership. This could have important implications for how to target a diesel car scrappage scheme, which is currently been discussed as a means through which to encourage the replacement of older diesel cars. For instance, restricting access to the scheme to those owners that reside in Air Quality Management Areas (i.e. where there’s an air quality problem) could prove ineffective if the problem is being generated primarily by individuals driving in highly polluting cars from further afield.