The Natural Resources Defense Council and the University of California–Berkeley are teaming up for a yearlong study of the environmental impacts of ride-hailing companies like Uber and Lyft. The researchers will take a hard look at the claims by those companies that the rise in ride-hailing corresponds with a drop in personal car ownership. And as an added bonus, they'll be doing it with cooperation from those two companies.

Ride-hailing companies have pushed back against the idea that their explosive growth over the last few years has led to more, not fewer, cars on the road. Earlier this year, Uber clashed with the city of New York over an attempt by Mayor Bill de Blasio to cap the San Francisco company's growth in his city at 1 percent while the effects of ride-hailing on traffic and pollution could be studied. Uber carpet bombed the city with negative advertising and de Blasio eventually rescinded his plan.

"There could be a detrimental effect."

The NRDC-Berkeley team will look at the environmental impact of ride-hailing on the nation as a whole. Amanda Eaken, deputy director for urban solutions at the environmental policy group, said those effects have yet to be fully studied.

"We don't yet understand what impact Uber and Lyft are having on our transportation system," she told The Verge. "Some people speculate that they are enabling people to live in cities without owning a car, which both saves them money — average cost to own a car is $9,000 a year — but also we know when people don't own cars they drive less. No big surprise."

She added, "There could certainly be environmental benefits from these companies. On the other hand, some speculate that people are using Uber and Lyft instead of walking, biking, or transit. So there could be a detrimental effect."

Earlier this year, Eaken, a San Francisco resident, went car-free by selling her Toyota Prius, knowing she could get access to a vehicle on-demand at the push of a button. Now she wants to see how scaleable her experience is.

Susan Shaheen, co-director of UC-Berkeley's Transportation Sustainability Research Center, said the study will include two key components: activity data from Uber and Lyft; and a survey of rideshare users. The survey will gather impressions of users about ride-hailing, their socioeconomic data, as well as "what they were doing before and how they would have taken the trip otherwise," Shaheen explained.

Uber has made no secret its ultimate goal is make car ownership a thing of the past. After all, it helps bring a benevolent, environmentally friendly glow to a company that has grown at a pace similar to a virus in a global pandemic. And it's often used as a fallback when the company is challenged by critics who question the way Uber and its ride-hailing peers treats their drivers and their disregard for regulations designed to promote safety and protect consumers.

The NRDC-Berkeley study will hopefully help settle some of these questions surrounding the environmental benefits and costs of ride-hailing. Previous research has studied the effects of carsharing services like ZipCar and Flexcar, but this would be the first academic study of transportation network companies like Uber and Lyft.

Does carpooling compliment or compete with mass transit?

In addition to challenging the environmental claims made by ride-hailing companies, the researchers will look at how carpooling services like UberPool and Lyft Line compete with or compliment mass transit in cities where they are available.

Eaken said the research will hopefully be published in the summer or fall of 2016. And she said her group is in talks with Uber and Lyft about providing new data to help inform the study. But neither company will have any editorial control over the results — that will be completely in the hands of the researchers, both Eaken and Shaheen said. "This is an independent evaluation," Shaheen added.