The colour coded labels better illustrate the information on carbon dioxide emissions per kilometre and fuel consumption that dealers have been obliged to display since January 2001.
Two formats are being piloted over the course of a year at volunteer dealerships to see which gains greater acceptance.
Both feature CO2 levels and their VED bands, and one will incorporate this into EU energy bands, similar to those already used on fridges.
One of the formats will give cars that emit 100g/km or less of carbon dioxide a green label and cars that emit 200g/km and over a red label. Emission levels for the other format being trialled start at 120g/km and go up to 185g/km. Blue, pink, yellow and orange are used to represent emissions between the lowest and highest levels. A Department for Transport spokeswoman said company car tax bands would be included on the information.
Transport minister David Jamieson said: 'Motorists see the environmental effect of different cars are increasingly important – especially now that the new vehicle excise duty system and company car tax are based on a car's CO2 emissions.
'Consumers are already familiar with the EU energy labels used for domestic white goods. This label helps them compare models and purchase the most energy efficient product. We believe this will make for an effective information label that will encourage both consumers to buy greener cars and manufacturers to continue to develop more environmentally friendly products.'