Transportation activity is a major source of emissions related to the combustion of fossil fuels, and accounted for 33% of emissions and 37% of growth in energy-related emission sources since 1990. Of particular note was the 109% increase in the emissions from light-duty gasoline trucks, reflecting the growing popularity of sport-utility vehicles, vans and light trucks. These vehicles, which emit, on average, 40% more GHG emissions per kilometre than gasoline automobiles, increased emissions.