The average new car in 2009 emitted 149.5g/km of carbon dioxide, down 5.4% on 2008 levels.
The rate of reduction is the best on record, three times the average rate achieved since data was first measured in 1997.
Reductions in average emissions were made across all model segments with MPVs (-28.6%) and 4x4s (-27.4%) making the biggest improvement against their 1997 base levels, according to figures from the Society of Motor Manufacturers and Traders’ New Car CO2 Report.
Minis and specialist sports cars made the biggest reduction over the past year falling 6.7% and 6.3% respectively on 2008 figures.
2009 saw the 12th successive annual drop in average new car CO2 emissions, but the rate of decline was increased by the recession and scrappage scheme steering buyers towards more fuel-efficient models. The average car bought under the scheme emitted 133.3g/km, 26.8% less CO2 than the average scrapped car.
In total, 27.6% of the cars registered in the UK in 2009 emitted less than 130g/km, the target set in the European CO2 regulation for 2015. In addition, showing the influence of the CO2-based road tax system, Band E (131-140g/km) proved the most popular with new car buyers, compared to Band H (166-175g/km) in 1997.
Paul Everitt, SMMT chief executive said: “Vehicle manufacturers have invested heavily in improving conventional technologies and bringing advanced systems to market that reduce the environmental impact of new vehicles.
“While scrappage incentives made a positive contribution to fleet renewal in 2009, there is a risk that over the next few years, motorists may be deterred from investing in the latest technology.
“Developing a long-term and consistent approach to vehicle taxation and environmental incentives will be important in maintaining the current rate of improvement.”
The adoption of the new car CO2 regulation in December 2009 set a phase-in target for vehicle manufacturers to ensure their average fleet emissions do not exceed 130g/km by 2015.