From Planetizen:

Multiple Studies Find Ride-Hailing Contributes to Congestion and Transit Losses

Surveys on ride-hailing conducted by regional planning agencies, academic institutions, and public transit agencies throughout the U.S. reviewed by the Associated Press largely led to the same conclusion: more traffic and reduced use of transit.

One of the most comprehensive studies on ride-hailing which surveyed 4,000 users in seven major metropolitan areas was released last October by UC Davis Institute of Transportation Studies (ITS) …

The study “found that a large portion of travelers are substituting ride-hailing in place of public transit, biking, and walking trips, or would not have made the trips at all,” wrote Clewlow

A ridership study [pdf] also released last October by the Massachusetts Bay Transportation Authority … found that “30% of passengers across all modes report that using [ride-hailing] services reduces their use of the MBTA.”

The two studies were among many reviewed by Steve LeBlanc of the Associated Press on Feb. 25. All but one conducted by Seattle-based firm INRIX that evaluated traffic congestion in London found transportation network companies (TNCs) contributing to traffic congestion and transit ridership reductions.

“The emerging consensus is that ride-sharing (is) increasing congestion,” said Christo Wilson, a professor of computer science at Boston’s Northeastern University who has analyzed Uber’s surge pricing.