Study: Full Electrification of Uber, Lyft Offers Marginal Benefits

While both Uber and Lyft ride-hailing services have pledged to fully electrify their vehicle fleets by 2030 in the U. S., a new study from researchers at the University of Michigan in Ann Arbor and Carnegie Mellon University in Pittsburgh estimates that the overall benefits to society of switching ride-hailing vehicles from gasoline to electric would be very modest — on average, a 3 percent gain per trip when other ”costs on society” are factored in.
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EV Uber car
A recent U-M joint study indicates that electrifying Uber vehicles won’t help the environment as much as many people think. // Photo courtesy of Uber

While both Uber and Lyft ride-hailing services have pledged to fully electrify their vehicle fleets by 2030 in the U. S., a new study from researchers at the University of Michigan in Ann Arbor and Carnegie Mellon University in Pittsburgh estimates that the overall benefits to society of switching ride-hailing vehicles from gasoline to electric would be very modest — on average, a 3 percent gain per trip when other “costs on society” are factored in.

The move would eliminate tailpipe pollution while shifting emissions to the power plants that provide electricity to charge EV batteries, likely resulting in a significant drop in overall emissions of climate-warming greenhouse gases.

Though that may sound beneficial, societal costs include increased traffic congestion, collision risk, and noise due to Uber and Lyft drivers traveling to and from fast-charging stations, according to the study published online on June 1 in the Environmental Science & Technology journal.

“Our simulation showed that electric vehicles drive greater distances without a passenger than do gasoline vehicles, since EVs have to travel to chargers more often than gasoline vehicles have to refuel,” says Parth Vaishnav, the study’s senior author and assistant professor at U-M’s School for Environment and Sustainability.

“Furthermore, fast chargers are not as ubiquitous as gas stations, which means EVs have to travel farther each time they refuel than gasoline vehicles.”

In their simulation, the researchers used a new high-resolution model called AgentX with real-world Uber and Lyft trip data collected in the Chicago area from 2019 to 2022. Chicago is one of the largest ride-hailing markets in the country, and the number of daily trips averaged roughly 300,000 prior to the COVID-19 pandemic.

The researchers modeled more than a million Uber and Lyft trips taken on weekdays, weekends, and during different seasons. They included trips taken before the pandemic started, as well as trips during the period after the widespread rollout of vaccines.

A set of standard economic tools was used to express costs to society in terms of dollars. Though the study results are specific to Chicago, the findings likely apply more broadly.

The study found that:

  • Electrification of Chicago’s ride-hailing fleets would reduce lifetime greenhouse gas emissions by 40 percent-45 percent when compared to gasoline-powered vehicles. The reduction is largely due to the greater efficiency of electric vehicles.
  • Health impacts from local air pollution would increase an estimated 6 percent to 11 percent per trip, on average, due to higher concentrations of local pollutants (such as sulfur dioxide, nitrogen oxides and particulate matter) from fossil fuel-burning power plants.
  • Extra driving to and from charging stations would increase traffic-related harms to society (congestion, crash risk and noise) by 2 percent to 3 percent per trip.
  • Overall, full electrification of ride-hailing would reduce total harms to society by about 3 percent per trip.
  • A 3 percent reduction in costs to society translates to about $1.5 million per year in savings for the city of Chicago. To put that number in context, ride-hailing is estimated to generate $4 million to $5 million in revenues per day in Chicago.

“It may seem counterintuitive that overall costs to society fall so little, even though greenhouse gas emissions are substantially reduced by the switch to EVs,” says Aniruddh Mohan, study lead author and formerly a doctoral student under Vaishnav at Carnegie Mellon and now a postdoctoral fellow at Princeton University.

“But on a per-mile basis, greenhouse gas emissions are a very small part of the total costs imposed on society by these vehicles. The costs are dominated by traffic externalities —congestion, crash risk and noise — which are directly correlated with vehicle distance traveled. And vehicle distance traveled will increase with electrification.”

About 80 percent of the total costs to society result from traffic-related factors, while 20 percent are due to emissions, according to the study.

The assessment includes the cradle-to-grave costs to society of building, operating, and disposing of EVs and gasoline-powered vehicles. Those lifetime costs include battery manufacturing, gasoline refining, and vehicle construction.

For EVs, the researchers looked at battery size and how it affects vehicle impacts on the environment. Making smaller battery packs requires less energy and leads to lighter vehicles. The thinking went that this might lead to greenhouse gas emissions savings.

To their surprise, smaller battery packs did not help. A smaller battery pack meant that EV drivers visited chargers more often, and those additional miles canceled emissions gains from using a smaller battery pack, according to the study.

“Overall, our findings made it very clear that a large part of the damage that cars cause is unrelated to their air emissions and is therefore unlikely to be eliminated by electrification,” says Vaishnav. “Electrification is a small win for society. A bigger win would be to dramatically reduce our dependence on cars. Policies that decrease vehicle distance traveled through investments in public transit and infrastructure for biking and walking, or that reduce crash risk by improved vehicle safety, are critical.”

Study authors, in addition to Vaishnav and Mohan, are Matthew Bruchon and Jeremy Michalek of Carnegie Mellon University. The work was supported in part by a grant from Carnegie Mellon University’s Wilton E. Scott Institute for Energy Innovation.

To read the full study, go here.