If something close to the higher-end trajectory occurs, fuel economy improvement will be even more important to contain the rise in global CO2 emissions. And other complementary measures, such as careful land-use planning, travel demand management, development of high quality transit systems where these provide more efficient trans- port services than private cars, and strong shifts to low-carbon fuels, will be needed to help move toward outright reductions in CO2 and reach lev- els well below those of 2005. In any case, cutting vehicle fuel use per kilometre by half by 2050 is central to transforming current trends into a more sustainable.
