CHANGES to the company car tax system last year have encouraged drivers to choose vehicles with lower carbon dioxide emissions, two new studies have found.

Godfrey Davis Contract Hire (GDCH) and Monks Partnership have produced reports that confirm the average company car now produces lower C02 emissions than it did 12 months ago.

GDCH estimates the fall to be about 5% with figures showing the average C02 emissions of vehicles on its fleets in January was 179.7g/km, compared to 188.5g/km in January 2002. Diesels accounted for 28.6% of GDCH's fleet a year ago but today they account for 41.5%.

In its annual survey of company car policy, Monks Partnership, part of PricewaterhouseCoopers, found most employees now select a cleaner car.

Of the 180 companies which responded to the survey, 92% said employees had selected cars with lower CO2 emission levels, with 83% reporting an increase of between 15% and 20% in the percentage of drivers selecting diesel-engined cars. More than a third (35%) of companies thought there would be a move to hybrid dual-fuel cars.

The report also found that 40% of respondents had employees who had previously taken a cash-for-car allowance and now expressed an interest in moving back to a company car.

Monks Partnership report editor David Atkins said: 'The changes brought in last year are achieving the Government's aims of promoting lower polluting, fuel-efficient cars and removing the incentive to drive unnecessary business miles.'

Nigel Underdown, head of customer relationships at Bank of Scotland Vehicle Management, which owns GDCH, said: 'In the past, diesel was not an acceptable alternative for management, but the refinement and performance offered by new-generation engines have radically altered this perception.'