Uber and Lyft have long advertised their ride-hailing services as deterrents from traffic congestion in dense cities. But a new study found the services — even their shared rides — leading to at least a 160 percent increase of cars driving on urban streets.

The study from New York City-based firm Schaller Consulting examined published reports, news articles, a national travel survey and trip data from the past 18 months to deliver a report on the impact of transportation network companies — better known as ride-hail or ride share, such as Uber and Lyft.

The study published Wednesday concluded that without wide-reaching public policy regulations, “big American cities are likely to be overwhelmed with more automobility, more traffic and less transit.” And once ride share enters the self-driving arena, the study forecasts, these cities will grow even more overwhelmed in the future.

“Tech companies, automakers and others are currently racing toward an autonomous future that envisions shared, door-to-door ride services weaning people from personal autos and combining the convenience of TNCs with the space efficiency of shared trips,” reads the report. “Today’s TNC experience, however, calls into question theviability of the door-to-door shared service model.”

Uber and Lyft, in statements to this news organization, pushed back on the study, saying it was “fundamentally flawed.” Lyft spokesperson Campbell Matthews called Bruce Schaller, the study’s author, a “known taxicab consultant,” who works in an industry most adversely affected by the advent of ride-hailing companies. Schaller previously worked for New York City’s Department of Transportation and the city’s Taxi and Limousine Commission.

Matthews pointed to various studies contradicting Schaller’s findings. One was from the public-interest organization Shared-Use Mobility Center, which earlier this year found “no clear relationship between the level of rush-hour TNC use and longer-term changes in public transit usage.”

“These studies also show that Lyft users are more likely to use public transportation, not less,” Matthews said.

Uber spokesperson Matthew Wing said the company “wholeheartedly agree with several of Mr. Schaller’s proposed public policies,” but said the study ignored important facets, such as the mobility benefits ride shares provide to low income groups in traditionally underserved neighborhoods

For years, Uber, Lyft and other companies argued their services — particularly shared rides — can drastically help reduce traffic in urban cities. In a 2017 online essay titled “The End of Traffic”, Lyft co-founders John Zimmer and Logan Green argue that if all New York City single-occupancy taxi rides were replaced with Lyft Line shared rides, it would cut 75 percent of vehicles off the road.

Reducing the number of cars in urban centers, the study went on to say, is the only way to reduce traffic congestion. The study proposed limiting parking supply and limiting or banning low-occupancy vehicles from certain streets; mandating TNCs meet certain occupancy levels or time with passengers during trips to increase efficiency; and provide frequent bus service and rail service wherever available.

“The overall vision is thus for less traffic and greater ease of movement for everyone regardless of mode for a given trip,” reads the report.

For shared rides in nine of the densest metropolitan areas in the United States, TNCs added 2.6 new miles of traffic for every 1 mile it took off from personal cars — a 160 percent increase. Private rides were slightly worse for traffic, as TNCs added 2.8 new miles of traffic.

The study argues lofty goals set by TNCs to increase share rides won’t reduce traffic. For example, Lyft will add 2.2 new miles of traffic, even if it met its goal of share rides composing at least 50 percent of all Lyft rides by 2022.

New traffic miles are added as most users switch from non-auto modes of transportation, such as public transportation, walking and bicycling, to use TNCs and drivers often face long distances to reach their pick-up location, according to the study. And even at times, shared rides involve just one passenger, inflating the mileage.

TNCs continue to grow in popularity in the United States. TNCs transported 2.61 billion passengers in 2017, a 37 percent increase from 1.90 billion a year prior, according to the study. And 70 percent of Uber and Lyft trips occurred in nine metropolitan areas, including San Francisco.

Despite the growth of TNC riderships, the demographics of riders remain limited, according to the study. People living in or nearby city centers, aged between 25 and 34, college-educated and making more than $50,000 used TNCs at least twice as much as their less wealthy, suburban and older counterparts.