Study: Uber, Lyft impact on San Francisco traffic

SAN FRANCISCO (KGO) -- Uber and Lyft may be causing more traffic congestion in San Francisco than previously thought.

The rideshare companies conducted their own study.

They say Uber and Lyft drivers account for about 13 percent of all miles driven on an average day in the city.

A previous study by the city's transportation authority estimated that number was 6 percent in 2016.