Uber and Lyft concede they play role in traffic congestion in the District and other urban areas

About 1 in 15 miles driven in the District is in an Uber or Lyft vehicle, according to a study that offers long-sought details of the services’ impact on traffic in urban areas.

Supporters of the ride-hailing apps have long billed them as a way to ease traffic woes by encouraging people to give up their personal vehicles or leave them parked. But company data released this week demonstrate how the firms represent a significant part of the traffic mix.