Scottish Futures Trust (SFT) and Transport Scotland (TS) identified that current Plug-in-Vehicle (PiV) registration data may not be taking full account of how PiVs are obtained and used, resulting in the potential underreporting of vehicle numbers in Scotland. City Science was commissioned by SFT to explore if PiVs are being underreported in Scotland, and if they are, to develop a methodology and spreadsheet tool, to support a more accurate estimation of PiV uptake.
This Study had two core objectives:
- To investigate if the currently available PiV licensing data underestimates PiV uptake in Scotland, and if so, to what extent.
- To develop a revised methodology and spreadsheet tool that supports a more accurate estimation of PiV uptake in Scotland.
We also provided evidence-led recommendations to support future interpretation and reporting of PiV registration and licensing data.
City Science Response
This project comprised of two key steps:
Assess Existing Data: The key data source for PiV statistics at present is the vehicle registration data published by the Driver & Vehicle Licensing Agency (DVLA) via the Department for Transport (DfT). We reviewed this data source for completeness, accuracy, and consistency. We then reviewed other data sources including the Society of Motor Manufacturers & Traders (SMMT) and Road Traffic & Census data.
Develop a Revised Approach for Estimating PiV Uptake: Based on the findings from the data review, we developed a new approach and a spreadsheet tool to more accurately estimate PiV uptake in Scotland.
We identified two key issues that result in the underreporting of PiV uptake in Scotland:
- Unallocated Vehicles: DfT data has approximately 1-2% of vehicles unallocated, which relates to vehicles that do not have a registered keeper and/or postcode, due to errors (e.g. the registration numbers being input incorrectly).
- Inconsistencies between Privately Registered Vehicles & Company Registered Vehicles: The percentages of company PiV cars and LGVs registered in Scotland (5% and 4% respectively) are significantly lower than the percentages of company cars and LGVs registered in Scotland, for all fuel types (6% and 7% respectively). This relates to the following reasons:
- Leasing Companies: Company-registered cars were concentrated in a few local authorities where we assume the major car leasing companies are located.
- Scottish Commuters to England: Scottish residents who commute to England may register their PiV at company locations. This is supported by analysis that shows company registered PiV are concentrated in the North West region (17% compared with 5% in Scotland).
- The Impact of Headquarters: Employees may be working for companies in Scotland but with Headquarters in England, as a result company cars may be registered outside Scotland.
In response to the challenge of accurately predicting PiV uptake in Scotland, we developed a three-step approach:
- Redistributing the unallocated PiVs
- Estimating the number of PiVs that were kept and used by Scottish residents who work in England
- Re-estimating the number of company registered PiVs in Scotland
Our revised tool provides a lower and upper range for estimating uptake. Our findings indicate that the upper range provides the most realistic indication of actual PiV uptake in Scotland. Utilisation of this method will avoid the significant underreporting of PiV uptake which our analysis indicates stood at 16% for Q3 of 2022.
Our work was referenced by Transport Scotland in its announcement of the Vision for Scotland’s Public Electric Vehicle Charging Network.
“It is also encouraging to learn about the City Science study published by the Scottish Futures Trust, showing the number of electric vehicles in Scotland to be much greater than UK government data suggests. It is clear that we are passing a tipping point in uptake of electric vehicles and that demand is there for investment in the charging network of the future…”
Fiona Hyslop, Minister for Transport, Transport Scotland.
You can download a copy of the final report here.