Autonomous vehicles used as zero-emission taxis would create less pollution than human-driven taxis and would be more profitable, according to a new study from Lawrence Berkeley National Laboratory. 

The per-mile greenhouse gas emissions of an electric vehicle deployed as a self-driving taxi in 2030 would be 63 to 82 percent lower than a projected 2030 consumer-driven hybrid vehicle and 90 percent lower than a 2014 gasoline-powered vehicle, according to the study.

An economic analysis found that in 2030, the total cost of ownership of an electric vehicle was still expected to be higher than owning and operating a gasoline-powered car. If the vehicle is driven 40,000 to 70,000 miles per year, which is typical for U.S. taxis, an alternative-fuel vehicle, either hydrogen fuel cell or electrical battery, would be the most cost-effective option. By 2030, autonomous taxis could be far cheaper than their driven counterparts.

The study's findings were based on costs for maintenance, fuel, insurance, and the purchase price of the vehicle. Although there is a higher initial cost for a more efficient car, the per-mile cost of fuel is lower, so the savings would pay for the extra investment. 

"When we first started looking at autonomous vehicles, we found that, of all the variables we could consider, the use of autonomous vehicles as part of a shared transit system seemed to be the biggest lever that pointed to lower energy use per mile," said Jeff Greenblatt, who produced the study with Samveg Saxena.

If five percent of 2030 vehicle sales (about 800,000 vehicles) were shifted to autonomous taxis that would save about seven million barrels of oil per year and reduce annual greenhouse gas emissions by approximately 2.1 to 2.4 million metric tons of CO2 per year, acccording to Greenblatt and Saxena's estimates. This would be equal to emissions savings from more than 1,000 two-megawatt wind turbines.

For more information on the study, visit www.lbl.gov.