If you are buying a new or second-hand car it is important to consider the fuel efficiency as this will affect the running costs and the amount of road tax that you pay. Cars manufactured after 2003 are now banded A to G, this affects the amount of road tax you pay, and may in the future affect charges in congestion zones and parking charges. It is also worth considering resale value, if you have a high band car, and you wish to sell it several years later the price it will attract may be reduced if these measures come in.