The reduction in CO2 emissions is thanks to fleets leasing greener cars and demanding that their drivers cover fewer annual business miles.
As a result, British fleets have cut their carbon footprint by three million tonnes over the past three years.
According to figures from the British Vehicle Rental and Leasing Association (BVRLA), this represents the equivalent of one-and-a-half tonnes of CO2 saved for every car run by its members.
“Our members and their customers are doing more than just choosing lower polluting cars… they’re covering fewer miles.” said the BVRLA’s director general, John Lewis.
“Average mileages have reduced from more than 25,000 miles per annum to 21,643 miles last year. Put these two areas together and this is a resounding success in our commitment to reducing greenhouse gas emissions in the fleet sector.”
The figures were obtained from a survey of fleets carried out at the end of 2007.
From this, the BVRLA discovered that average CO2 emissions have reduced from 171.8g/km in 2003 to 157.4g/km in 2007.
This outstrips the decreases across new car registrations as a whole.
According to the Society of Motor Manufacturers and Traders (SMMT), in 2007 the average new car CO2 figure dropped 1.4% year-on-year to 164.9g/km, a fall of 13.1% since 1997.
The SMMT claims that improvements in vehicle technology have seen savings of around one million tonnes per year across the entire new vehicle parc, which covers both fleet and private registrations.
This figure, compared alongside the BVRLA’s research, suggests that almost all the CO2 savings are coming through the registrations of fleet vehicles, and that the effect on private buyers of tax incentives such as graduated VED are less effective than those incentives in the fleet market.
Carbon emissions in the fleet sector have dropped steadily since the introduction of CO2-based company car tax.
With Class 1A National Insurance Contributions also related to CO2, there are now fiscal incentives for drivers and employers to choose lower emission cars. Alongside tax, the high price of fuel is also concentrating fleet minds.
Unknown is the effect of schemes such as the London congestion charge on driver choice.
No decision has yet been made on whether there will be a 100% discount for sub-120g/km cars entering the zone, although an announcement is likely any day.