Company car drivers could see the amount of tax they pay change after the European Commission announced it would be changing the way car emissions are tested.
As well as the CO2 figure tests changing, the way fuel economy is determined could also be reformed to reflect 'real-world' driving conditions.
The tests at the moment are done in two parts that measure both emissions and economy. The first part is done with a cold engine, on a rolling road and contains lots of stops and starts up to 31mph, to replicate city driving. The second part is meant to replicate out-of-town driving and up to speeds of 75mph.
The figures are then taken to give the Urban MPG, Extra Urban MPG and Combined MPG as well as the cars CO2 emissions.
Any change in the CO2 testing could have a big impact on business drivers and change how much money they have to pay for their car as company car BIK tax is based on this figure, while economy figures help map out the cars running costs.
The plans are still some way off - the official white paper says that the alterations should be in place by 2013. However, governments and interest groups will have some influence on any changes before they happen.