San Francisco (KRON) – A new report requested by Lyft and Uber found that the ride share companies account for 12 to 14 percent of “vehicle miles traveled” in San Francisco, the highest of the cities surveyed.

Factors that contribute to this include San Francisco’s dense population which is squeezed into such a small physical space. In fact, the study states that San Francisco contains 12 percent of the regional population in less than one percent of regional landmass.

San Francisco also has the lowest car ownership in the Bay Area, as well as the most robust internal transit system, resulting in the least amount of overall miles traveled by car.

On average, ride shares account for just four percent of miles traveled in the other cities surveyed, which include Boston, Chicago, Los Angeles, Seattle, and Washington D.C.

The only other “core county” that comes close to San Francisco is Suffolk County, which includes Boston, and boasts eight percent of miles traveled through ride shares.

When compared to “metro regions” the Bay Area is much closer to the rest of the nation. On average, 1.8 percent of miles traveled in metro regions are through ride shares and the Bay Area ranks the highest at 2.7 percent. Bay Area counties that are included in the study’s “metro regions” include, San Francisco, Marin, Sonoma, Napa, Solano, Contra Costa, Alameda, Santa Clara and San Mateo.

Data was collected during September 2018 to minimize holiday traffic, and included weekends where patterns may have been different from the week. The full report can be read here.