Vehicles tested in the UK programme showed no evidence of car manufacturers, apart from the VW Group, fitting devices to defeat the approved emissions test programme according to the UK government’s research into emission levels from leading diesel car models.

The tests have not detected evidence of test cycle manipulation strategies as used by the Volkswagen (VW) Group. Tests have provided further evidence that nitrogen oxide (NOₓ) emissions are higher in real world conditions and on the test track than they are in laboratory conditions. This was the case for all manufacturers’ vehicles, with results varying significantly between different makes and models.

Tests have been carried out on a total of 56 different vehicle types in Germany and 37 different vehicle types in the UK, over a period of 6 months. The Vehicle Certification Agency on behalf of the Department for Transport tested a representative selection of the UK’s top selling diesel vehicles. The findings provide a snapshot of exhaust emissions from those diesel models when tested in the laboratory, on a test track and during typical road use.

Existing lab tests designed to ensure emission limits are met have been shown to be inadequate and this is why the UK has secured a tough new Europe-wide ‘real driving emissions’ test. From next year, vehicles will have to meet emissions limits in real driving conditions across a wide range of typical operating temperatures. This will improve consumer confidence in manufacturers. The UK will be working to ensure that the new rules for real driving emissions and type approval are robust, deliver the expected outcomes and that manufacturers behave consistently.