Abstract
In recent years the demand of energy in the European Union has been continuously increasing as a consequence of society evolution and economic development. In the meanwhile, energy consumption sharing for different applications considerably changed, with a trend to higher amounts of energy used for transport, whose weight now approaches one third of total energy. In the transport area, about 85 per cent of energy is used for road applications (goods and passengers). In absolute terms, the amount of energy used for road transport increased of almost 50 per cent between 1980 and 1995. {1}