The average carbon emissions of new company cars fell to an all-time low of 126g/km during the first six months of 2013, according to data from ALD Automotive.
The data, based on the96,000 vehicles ALD operates, shows that over the past 10 years average CO2 emissions have fallen by 24% as manufacturers continue to introduce efficient low CO2 models into the marketplace and record numbers are ordered by businesses.
The figures show that the rate of reduction in emissions has improved more recently with average CO2 emissions falling by 20% in past five years alone and now below the UK's average of 133g/km in 2012.
ALD's analysis of company cars it has delivered to customers this year also reveals that 70.5% have been diesel-powered, 29% petrol-engine with 0.5% being alternatively fuelled vehicles.
This has coincided with a trend of employees travelling fewer miles as part of a continuing focus on the reduction of vehicle operating costs, and looks set to continue in the future.
ALD's research shows average mileage fell by more than 2,400 miles, from 18,500 miles in the first six months of 2012 to 16,000 in the first half of 2013.
Over the past decade average mileage has fallen by more than 6,000 miles - a reduction of 28%.
Currently, more than 50% of ALD Automotive's own company fleet are sub-119 g/km vehicles, allowing ALD employees to benefit from reduced BIK with 7% in the 99g/km and below category.
Legislation continues to be the driving factor in pushing emission levels down and the trend will continue.
From April next year the 10% rate will be abolished with increases of 1% for vehicles which emit between 76g/km and 210 g/km of CO2, to a maximum of 35%.
Furthermore, from October 2013 all large and medium-sized companies must now declare carbon emissions data in their annual reports for the entire organisation, including company vehicles.
Mel Dawson, managing director for ALD, said: "Company car fleets have come a long way over the last ten years in dramatically reducing their carbon footprint and delivering significant financial savings to businesses.
"Carbon emissions remain very much under the spotlight and, with emissions and taxation inextricably linked, we are working closely with our customers to help them stay one step ahead of legislation."