The online survey also assessed the level of knowledge of car buyers regarding their car’s official performance
data by asking participants for ‘official figures’ for the car recently purchased. The question gave them the
opportunity to enter values for: fuel economy (in ‘mpg’ and ‘litres/100km’), fuel cost (per year, per month and
per mile), engine size (litres), CO2 emissions (g/km) and road tax (VED band and annual cost). Participants’
responses were checked with their car’s actual official data using the CarweB database based on a car’s Vehicle
Registration Mark (provided on a voluntary basis by over 75% of the online sample).