Motorists and car dealers are being encouraged to reduce greenhouse gas emissions by making sure their vehicles are properly maintianed.
The National Automobile Dealers Association (NADA) in the US has created a green check list to help drivers and sellers make sure their cars have as little effect on
air quality as possible.
Included on its list are factors that have the greatest effect on fuel economy, such as oil and air filters, tyre pressure, emission controls and engine performance.
Annette Sykora, chairman of the NADA, said: "Dealers are responding with enthusiasm."
She added that with much attention being paid to greenhouse gas emissions and fuel prices continuing to rise, there has never been a bigger incentive for motorists to improve the fuel economy of their cars.
In December 2007, the European Environment Agency claimed a number of EU states would miss the legally-binding emissions targets for four air pollutants by 2010.