Uber and Lyft are causing even more traffic congestion in San Francisco than local experts once thought.

Ride-hail drivers account for roughly 13 percent of all miles driven on an average day in San Francisco. (Sarah Beth Maney/Special to S.F. Examiner)

Uber and Lyft are causing even more traffic congestion in San Francisco than local experts once thought.

Ride-hail drivers account for roughly 13 percent of all miles driven on an average day in San Francisco.

That’s double the amount estimated by researchers working for San Francisco county, who based their estimate off data collected in 2016.

Now, this new analysis, paid for by ride-hail giants Uber and Lyft themselves, using their own data, shows in just two years traffic impacts have grown far higher than San Francisco officials previously feared.

The disparity was first reported by CityLab, which looked at an estimate of vehicle miles traveled within The City for the San Francisco County Transportation Authority’s study, “TNC’s Today.” A transportation network company, or TNC, is the state designation for ride-hails like Uber and Lyft.

“This difference may be due to the continued increase in TNC use over the intervening two years,” Greg Erhardt a University of Kentucky civil engineering professor told CityLab, Monday. Erhardt conducted the 2016 study for San Francisco, which aimed to unearth how heavily Uber and Lyft contributed to traffic woes.

“With nearly double the (vehicle miles traveled for Uber and Lyft), we would expect the effect of (ride-hails) on congestion to be much higher in 2018 than was estimated for 2016 conditions,” Erhardt told CityLab.

The TNC’s Today study found that in 2016 Uber and Lyft accounted for 6.5 percent of all vehicle miles traveled on any San Francisco weekday. That study was conducted in 2016 but released in 2017. Those vehicle miles driven daily come from thousands of for-hire cars: On an average weekday, at least 5,700 Uber and Lyft vehicles swarm in key, lucrative neighborhoods in San Francisco, the study found. On Fridays that number hits 6,500.

At the time, the revelations in the study prompted condemnation from city officials.

“The data in this report confirms the widespread public perception that Transportation Network Companies comprise a significant share of traffic on our city streets,” Aaron Peskin, Chair of the San Francisco county Transportation Authority and District 3 Supervisor said in 2017, when the report was released. “As a Transit First City, we have to evaluate the impact these gig economy vehicles are having on our public transit and our already congested streets.”

Uber and Lyft’s new study, conducted by Fehr & Peers in six metropolitan regions in September 2018, found that Uber and Lyft accounted for as much as 13.4 percent of all vehicle miles traveled within San Francisco on any given weekday on the high end, and 12.2 percent at the low end.

While that’s twice-over the amount of vehicle miles traveled daily in San Francisco from the 2016 study, in the region the number of miles traveled by Uber and Lyft vehicles is still much lower, hovering around 2.7 percent of all miles traveled in the greater Bay Area.

In San Francisco, at least, those Uber and Lyft vehicles are empty either waiting for a ride request or heading to pick up a passenger roughly half of the time a vehicle is on the road, according to the Fehr & Peers study.

In a blog post published Monday, Chris Pangilinan, head of global policy for public transportation at Uber, defended the numbers revealed in the study, asserting they showed private vehicle driving accounted for most traffic.

“Although (ride-hails) are likely contributing to an increase in congestion, its scale is dwarfed by that of private cars and commercial traffic,” Pangilinan wrote.

While that may be true in five of the regions out of six from Uber and Lyft’s study, the study authors indicated that San Francisco was an exception. More people take public transit in San Francisco — from Muni to BART to Golden Gate Transit — and therefore, Uber and Lyft likely have a greater impact on local traffic congestion.

“San Francisco has a lower rate of car ownership compared to the rest of the Bay Area, as well as a robust internal transit system, and the lowest (Vehicle Miles Traveled) per Capita in the region,” the study’s authors wrote. “As such, the higher share of (Vehicle Miles Traveled) potentially associated with Lyft and Uber may reflect lower overall rates of driving and higher transit rates, as well as a less centralized location for freight passing through the region.”

joe@sfexaminer.com

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