Jon Walden claimed figures analysed by Lex showed that its fleet had seen drivers reduce their CO2 emissions by almost one tonne per year on a typical fleet contract between 2000 and 2006.
He adds that on the Lex fleet of 178,000 vehicles, that equates to an average CO2 reduction of nearly 171,000 tonnes per annum.
Walden said: ‘CO2 levels are obviously one of the key reasons for choosing a company car now, not just its size and practicality.
‘It’s clear company motorists are helping reduce their impact on the environment because it reduces their tax liability, but it’s now time for retail drivers to take CO2 just as seriously when making their purchasing decision.
‘These figures reinforce that company car drivers are having less of an impact on the environment than normal motorists, something which the government should be mindful of when next reconsidering motoring taxation levels.’
The company’s analysis shows that in the year 2000 its fleet of vehicles had a wide range of CO2 emissions with an average tax banding of 185g/km.
Today it is at 155g/km, equating to a fall of six tax bands over six years.
A wider choice of lower emitting cars is cited as one reason for the drop. Lex bosses say they now have cars on their fleet with a CO2 output as low as 110g/km, compared to 130g/km six years ago.
Drivers are also choosing smaller cars with fuel efficient diesel engines, with diesel power now accounting for 72% of its fleet, compared with almost 40% five years ago.