Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.

In 2021 and 2022 the ASA and CAP undertook a Climate Change and the Environment (CCE) project taking stock of the rules regulating environmental claims.  This project consisted of three concurrent strands:

  • Proactive regulation: proactively looking at environmental claims in several priority areas with a view to updating our position on emerging and existing themes and taking action against advertisers who use green claims in a way that is likely to mislead or cause harm. 
  • Standards fit for the 2020s: taking stock of how effective our rules and guidance are in governing environmental claims. 
  • Knowledge, education and communication: updating our existing resources to make them easily accessible, and creating new training materials and other educational resources to improve industry’s understanding and overall compliance with our rules on misleading and harmful environmental claims.

While this advice represents the current position, the ASA’s CCE project is now reviewing our approach to these issues, which may lead to further rulings and updates to this guidance.

The requirement to display fuel consumption ('mpg') and CO2 emissions figures in car ads is not a specific requirement of the CAP Code. However, if a business is involved in the supply of new cars in the UK, they must provide certain information as it is a statutory requirement.

The legislation that sets out the requirements for the display of that information is The Passenger Car (Fuel Consumption and CO2 Emissions Information) Regulations 2001 and amending 2004 and 2013 Regulations.

What are the figures based on?

Before September 2017, all cars advertised had CO2 and fuel consumption values based on the New European Driving Cycle test (NEDC).

Since then, the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) has been used. This is intended to produce more realistic CO2 and fuel consumption values: the WLTP testing regime aims to provide a closer representation of ‘real-world’ fuel consumption and CO2 figures. This applies to all vehicles, including fully electric, hybrid and plug-in electric hybrid vehicles (PHEVs).

Following a transitional phase, all relevant new car ads from 6 April 2020 onwards have been required to display WLTP figures only. 

Who ensures adverts are compliant?

The legislation that sets out the requirements for the display of that information is The Passenger Car (Fuel Consumption and CO2 Emissions Information) Regulations 2001 and amending 2004 and 2013 Regulations.

The  Vehicle Certification Agency (VCA) is the nominated UK enforcement body in monitoring all car advertisements to ensure they display the relevant fuel consumption and CO2 data. The VCA requires that text is easy to read, easily understandable and ‘no less prominent than the main part of the information.’ To help marketers and their agencies, the VCA has published Guidance Notes, to further clarify the requirements for advertising.

Does the CAP Code apply?

These statutory figures, in and of themselves, are not regulated by the ASA, and the CAP Code does not apply in terms of the inclusion or accuracy of the figures.  However, marketers should bear in mind that the CAP Code does still apply to claims made in ads and whether they are likely to mislead consumers.  As with all claims capable of objective substantiation, figures that relate to a vehicle’s fuel efficiency or emissions should be accurate and, if not to do so would mislead materially, the basis for their calculation should be adequately explained. 

For example claiming that a vehicle is capable of “returning a quite remarkable 68.9mpg on a combined cycle” should be representative of a figure likely to be achieved by consumers, or the basis for the figure should be suitably explained (Volkswagen Group UK Ltd t/a Audi, 27 March 2013).  Under the previous (NEDC) testing regime, the ASA accepted qualifications that made clear that the figures were obtained from laboratory testing, intended for comparisons between vehicles and may not reflect real driving results.

Marketers are therefore recommended to accompany all official fuel and CO2 figures (where the omission is likely to mislead consumers) with explanatory text along the lines of: “Figures are intended for comparability purposes. The fuel consumption you achieve under real life driving conditions and CO2 produced will depend upon a number of factors including the accessories fitted after registration, variations in driving styles, weather conditions and vehicle load”.

Range figures

More recently, this principle has been applied in several rulings concerning the advertised driving range of electrified vehicles. These figures, where presented, are also taken from test conditions laid out under the WLTP.

The ASA investigated whether several ads making similar claims, including a paid-for online ad which stated “The all-new Kia Niro – Niro EV up to 285 mile range”, presented a misleading and exaggerated impression of how far an electric vehicle might be likely to travel on a single charge. In that case, the advertiser said that this was the ‘Combined’ WLTP figure – and highlighted that this was the only range figure that they were legally allowed to reference.

The ASA concluded that the presentation of this figure was misleading, as the advertiser had not provided information to explain to consumers that this figure would be dependent on various real-world factors such as speed, style of driving, weather and route conditions, and the age and condition of the battery. It also noted that the WLTP range figure was based on a car’s battery charged to 100%, when the ASA understood that it was generally inadvisable to regularly charge an EV’s battery beyond 80%. The ruling states that the presentation of future claims such as this should avoid the implication that they are representative of a users’ likely experience when driving (Kia UK Ltd, 20 December 2023).

Similarly, claims about how far hybrid vehicles can travel using electric power alone should also be explained clearly. In 2023, the ASA investigated whether an for a full hybrid SUV which said "Up to 80% electric driving in the city" was misleading. The advertiser said that a qualification should have appeared in the ad stating "Actual real world driving results may vary. Internal Renault source 2022" - and that this testing regime was intended to replicate the WLTP. The ASA concluded that (irrespective of the qualifying text which should have appeared) the claim was ambiguous and therefore misleading, since there were various possible interpretations of the claim (reflecting the proportion of an individual journey, or 80% of the total journeys covered, for example). Without additional information to explain what the claim meant, it was deemed likely to mislead (Renault UK Ltd, 29 November 2023).

Again, marketers are advised to follow the principle that, if figures used are not necessarily representative of what will be achieved by consumers, they should qualify them with an explanation of the conditions under which the figures were achieved and highlight that they may not reflect actual consumer experience, explaining what factors would affect this.

See also Motoring: Zero emissions claims, Motoring: General environmental claims, Motoring: Hybrid and electric vehiclesEnvironmental: General “Green” claims and Advertising Guidance: misleading environmental claims and social responsibility

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