This chapter explores the extent to which the adoption of highly automated vehicles (AVs) will lead to carbon dioxide (CO2) emission reduction in the future. Additionally, policy implications are given. Based on existing literature, this chapter shows that the adoption of AVs will result in a modest improvement of CO2 emission per kilometer traveled compared to non-autonomous vehicles in the future. Combined with the expectations that AVs will lead to a modest to, even, high growth in vehicle kilometers traveled (VKT) compared to business as usual, the net energy and CO2 emission balance for AVs seems, at its best, to be neutral, but is probably negative. The potential accelerating role of AVs in relation to the uptake of electric vehicles might have the largest positive impacts on the CO2 emissions per kilometer driven, but this accelerating role of AV technology in relation to the uptake of electric vehicles is uncertain. For the time being the most useful policy implication to curb road transport CO2 emissions seems to be to continue with policies that promote the use of alternatives for fossil fuels, such as electricity.