SAN FRANCISCO (CNN NEWSOURCE) – Apparently you can partly blame ride-sharing companies for the time you spend in traffic.

Uber and Lyft tapped transportation consultants, Fehr and Peers, to conduct a study about congestion problems in several big cities.

The companies wanted to know if its drivers contributed to the total vehicle miles traveled in six major cities.

The list included Los Angeles, San Francisco, Boston, Chicago, Seattle, and Washington DC.

The study found that ridesharing was responsible for anywhere between two-percent to more than 13-percent of all vehicle miles traveled in a city.

And only around half of those miles were actually spent driving a passenger.

Uber’s head of Global Policy for Public Transportation points out that private and commercial vehicles still account for most of the congestion in a city.