One promise of ride-hailing companies like Uber and Lyft was fewer cars clogging city streets. But studies suggest the opposite: that ride-hailing companies are pulling riders off buses, subways, bicycles and their own feet and putting them in cars instead.

And in what could be a new wrinkle, a service by Uber called Express Pool now is seen as directly competing with mass transit.

Uber and Lyft argue that in Boston, for instance, they complement public transit by connecting riders to hubs like Logan Airport and South Station. But they have not released their own specific data about rides, leaving studies up to outside researchers.

And the impact of all those cars is becoming clear, said Christo Wilson, a professor of computer science at Boston’s Northeastern University, who has looked at Uber’s practice of surge pricing during heavy volume.

“The emerging consensus is that ride-sharing (is) increasing congestion,” Wilson said.

(SF Gate)