Berkeley, California - Since Uber, and then Lyft, came onto the ride-hailing scene in 2009 and 2012, respectively, the companies have extolled the environmental virtues of their services, claiming that their use reduces personal car ownership and the number of cars on the road.

But researchers at UC Berkeley and the Natural Resources Defense Council aren’t taking Uber and Lyft’s word for it. Instead, they’re joining forces to conduct a yearlong national study of the environmental impacts of these companies.

Some critics have raised concern that the skyrocketing growth of Uber and Lyft has led to more cars on the road, not fewer, and instead of walking, biking or taking transit, people are opting to hail a ride online.

Susan Shaheen, co-director of UC Berkeley’s Transportation Sustainability Research Center, says researchers will gather information from users about their socioeconomic status, ride-hailing habits and their modes of transportation before the companies hit the market.

Researchers aim to publish the study by fall 2016.