As autonomous vehicles work their way into everyday reality, the Energy Information Administration finds that the technology could change travel behavior and – along with that – raise energy use. The EIA’s analysis shows that widespread adoption of autonomous vehicles could increase overall light-duty vehicle travel and lead to more fuel use among that sector.

Light-duty vehicles, defined as automobiles under 10,000 pounds, account for 21 percent of total delivered end-use consumption. EIA says use of light-duty vehicles is already on the rise and expects travel in those vehicles will increase 18 percent by 2050, reaching 3.3 trillion miles. When the administration factors in autonomous vehicles, which are expected to experience a 31 percent sales boost, the mileage increased to 3.8 trillion.

EIA’s first reference case is based on those autonomous vehicles using conventional gasoline internal combustion engines. A second reference case considers battery electric and hybrid electric autonomous vehicles, also finding increased fuel consumption when compared to 2050 case levels without autonomous vehicles. In all cases, however, conventional gasoline engines were the most common technology powering light-duty vehicles.

According to the study, future transportation energy demand is still lower than in 2017, largely because of Corporate Average Fuel Economy (CAFE) and greenhouse-gas emissions standards on light-duty vehicle energy consumption. In the two cases with greater autonomous vehicle adoption, transportation energy demand is slightly higher than in the reference case, as the improved fuel economy associated with battery electric vehicles and hybrid electric vehicles only partially offsets the increase in travel demand.

In both of those cases, fuel use in public transit modes is affected by assumptions about how they could interact with autonomous vehicles. Large fleet long-haul commercial trucks are assumed to start using automation technology to improve fuel efficiency through platooning, where groups of vehicles travel in a tight formation to reduce aerodynamic drag. However, the energy consumption effects of these changes for commercial trucks or other modes such as mass transit are relatively small compared with the consumption changes in light-duty vehicles.