Auto Express conducted “Green or Gimmick” road tests on eight vehicles, which, it said, all produced higher emissions than advertised.

The manufacturer's official figures are based on laboratory tests conducted by the manufacturers, importers or independent test engineers, and do not always reflect driving conditions. The Toyota Prius, the most lauded hybrid model, produced 157g/km CO2 emissions, compared to the official figure of 104 g/km. The Honda Civic Hybrid's emission level was 171g/km, far higher than the 109g/km advertised figure. Toyota was however, praised for putting the most effort and expense into developing hybrid technology, and the Prius' strong global sales have helped to raise environmental awareness in the car market. The Civic Hybrid, Skoda Fabia, and Lexus GS 450h were branded as gimmicks by the magazine. The Fabia Greenline 1.4 TDi produced 153g/km CO2, compared to the 109 g/km official figure, and while it was praised for comfort and pricing, Auto Express said it was “not as green or economical as its older rivals”. While the Lexus GS 450h 3.5 V6SE's stated emissions figure is 185g/km, in the test it produced 244g/km. The Ford Focus Econetic, Mini Cooper Clubmand, VW Polo Bluemotion, and the Seat Ibiza Ecomotive all passed as “Green” in the test, but all also registered higher actual CO2 emissions than their official levels.