Trends in energy consumption and carbon dioxide emissions of private cars and buses in Hong Kong

Transport is the only sector where there has been a steady decrease in energy consumption in recent years, from 106,984 Terajoules in 2000 to 90,242 Terajoules in 2009. On the other hand, greenhouse gas emissions, of which carbon dioxide is the major constituent, for the transport sector has increased from 5940 kilotonnes to 7540 kilotonnes between 1990 and 2008. Among various transport modes, private cars and buses use more energy and produce more carbon dioxide emission. This paper attempts to use the data of three transport measures (vehicle-kilometer, vehicle fleet and passenger-kilometer) and four socio-economic factors (gross domestic product, per capita gross domestic product, population and composite consumer price index) from 1984 to 2007 to predict the energy consumption and carbon dioxide emissions of private cars and buses. The results show that the energy consumption of private cars and buses are predicted well by transfer function models using vehicle-kilometer as the only input variable. Policies to reduce this transportation usage measure may help to reduce transport energy use and carbon dioxide emissions.