Self-Driving Uber

CARB is considering new regulations to reduce greenhouse gas emissions from ride-sharing vehicles. 

The California Air Resources Board is considering new regulations to curb greenhouse gas emissions from a transportation sector that has grown heavily over the past decade: on-demand ride-sharing companies, such as Lyft and Uber.

CARB staff estimated that ride-sharing vehicles in California emitted about 301 grams of carbon dioxide per passenger mile traveled in 2018, which is about 50 percent higher than the state's passenger-vehicle fleet average of 203 gCO2/PMT, according to a December report. CARB staff also found that ride-sharing vehicles have a 7 percent lower passenger occupancy than regular passenger vehicles in the state, and that ride-share vehicles travel about 61 percent of their miles with a passenger or passengers.

The growth of ride-sharing in recent years raises uncertainties around its environmental impacts, the report said. CARB staff is now analyzing regulatory scenarios to address emissions and could include its findings in its Clean Miles Standard Regulation, expected to go to CARB's board of directors in December 2020.

The on-demand cars emit more GHGs in part because they travel at slower speeds than regular vehicles, CARB staff said. Generally, lower traveling speeds increase CO2 emissions per mile, and ride-sharing vehicles travel 10 miles per hour slower than the California passenger-vehicle fleet, which may negatively affect the vehicles' average in-use fuel efficiency relative to that of regular car trips, the report said.

CARB staff also looked at ride-sharing companies' use of zero-emission vehicles and determined that plug-in electric vehicles accounted for 43.6 million of 4.2 billion total miles traveled by ride-sharing vehicles in 2018 in the state. According to the report, there are about 640,000 ride-sharing vehicles in the state, mostly concentrated in urban areas such as San Diego, Los Angeles and San Francisco.

Bloomberg New Energy Finance, an organization that provides research on energy-related matters, projected the share of global vehicle miles traveled by ride-sharing companies will grow from about 5 percent at the time of the report to 19 percent by 2040. Ride-sharing vehicles in California accounted for about 1.2 percent of the total California light-duty vehicle miles traveled in 2018, according to the report. They were responsible for approximately 0.54 percent of the state's transportation-sector GHG emissions. In San Francisco, ride-sharing vehicles contributed to 15 percent of all intra-San Francisco vehicle trips in 2016, about 12 times the number of taxi trips in 2016, staff said.

California's transportation sector currently accounts for about 41 percent of the state's total GHG emissions. The state's transportation emissions increased 6 percent, or by 9 million metric tons of CO2-equivalent, from 2013 to 2017. CARB last year approved regulations to eliminate rebates for certain luxury electric vehicles and reduce rebates for all other eligible vehicle types in its clean-transportation program (see CEM No. 1562).

Ride-sharing companies must submit a GHG emissions-reduction plan to CARB by Jan. 1, 2022, and implement the plans in 2023.

Staff Writer

David Krause is an energy reporter covering the California Energy Commission and Air Resources Board. He writes about transportation, climate change, utilities, and wildfires. He has an MFA in Writing, an MA in English, and a BS in Civil Engineering.