How do ride-hailing companies like Uber and Lyft affect transportation decisions? Does ride-hailing help or hurt public transportation? Is it reducing the number of owned vehicles on the road?

A study by the University of California Davis’ Institute of Transportation Studies examined the adoption, utilization, and impacts of ride-hailing (Uber and Lyft) in the United States. The study looked at 4,000 users in seven major U.S. cities — Boston, Chicago, Los Angeles, New York, San Francisco Bay area, Seattle, and Washington, D.C. — between 2014 and 2016. It included residents from both urban and suburban areas.

In major cities, 21% of adults personally use ride-hailing services and an additional 9% use ride-hailing with friends, according to the study. Nearly a quarter (24%) of surveyors in metropolitan areas uses ride-hailing services on a weekly or daily basis. The top reason that ride-hailing users will choose a ride-hailing service over driving themselves is parking, followed by avoiding driving when drinking.

Ride-hailing users who also use transit have higher personal vehicle ownership rates than those who only use transit (52% versus 46%), according to the study. A higher number of “transit only” travelers have no household vehicle (41%) compared with “transit and ride-hail” travelers (30%). The majority of ride-hailing users (91%) haven’t made any decisions about vehicle ownership since they started using ride-hailing.

After picking ride-hailing, the average net change in transit use is a 6% reduction in major cities, according to the study. Ride-hailing reduces the number of Americans who use bus services (6% reduction) and light rail services (3% reduction). With ride-hailing services, commuter rail services did increase 3% in usage.

Key takeaways from the study include:

- Ride-hailing is used regularly by urban Americans and less by those in the suburbs.

- Ride-hailing users have similar vehicle ownership rates as everyone else.

- Ride-hailing users report a net decrease in their transit use.

- About half of ride-hailing trips (49% to 61%) would have been made by walking, biking, transit, or avoided altogether.