Study: Half of SF’s increase in traffic congestion due to Uber, Lyft

Uber and Lyft are making San Francisco traffic worse.

That’s according to a new report from the San Francisco County Transportation Authority, which found that traffic congestion throughout The City — measured in miles driven, vehicle speed, and traffic delays — has worsened from 2010 to 2016, with half of that slowdown attributable to the rise of ride-hails.

The City’s average traffic speed dropped from about 24 miles per hour in 2010 to about 20 M.P.H. in 2016, according to the report. And that impact is particularly noticeable during the evening commute, when ride-hail vehicles made up 60 percent of the increase in traffic from 6:30 p.m. onward, researchers found.

The transportation authority, which is responsible for traffic congestion management in San Francisco, studied traffic congestion between 2010 and 2016 in partnership with the University of Kentucky using a combination of existing data “scraped” from Uber and Lyft without their permission and traffic data from INRIX, a global transportation analytics firm, among other sources.

Although the report attributed half of The City’s increase in traffic congestion during that period to ride-hails, it attributed the other half of traffic increases on the 70,000 new city residents and 150,000 new jobs added to The City during that same period.

That study measured congestion from just about every angle experts use to slice up traffic: How much worse did traffic delays become? How many more miles did vehicles travel on city streets? How badly were those vehicles slowed down? And while not every street was looked at, due to lack of data, most major arteries in San Francisco were analyzed, said Joe Castiglione, deputy director of technology, data and analysis at the transportation authority.

“The question we’re trying to answer is, ‘Do (ride-hails) have an affect on congestion in San Francisco?’” Castiglione told reporters in a Monday briefing.

He added, simply: “They do.”

A bar graph shows the increase in hours of delay, a measure of traffic congestion, by supervisor district in San Francisco. Red percentages indicate the increase in hours of delay due to ride-hails, here referred to as TNC’s or “Transportation Network Companies,” the California state designation for Uber and Lyft. Pale yellow bars represent delays caused by employment growth, marigold bars represent delays caused by population growth. (Courtesy San Francisco County Transportation Authority)

Perhaps unsurprisingly, both Uber and Lyft hotly contest the findings.

Lyft called the report “flawed and an incomplete picture of the transit challenges San Francisco faces.” But while the company defended itself by arguing that Lyft usage was higher outside the evening commute, during bar-going hours, the company would not provide data on its utilization in San Francisco.

Uber said “this study fails to consider critical factors like the spike in tourism or the growth of freight deliveries.” The company supported its claim with data from San Francisco Travel, which shows only a 1.4 percent growth in travelers to San Francisco from 2016 to 2017.

The transportation authority’s results are similar to those found in other recent research. For instance, a study by University of Colorado researchers found Uber and Lyft increased the vehicle miles traveled in Denver by 83 percent.

In the San Francisco study, while ride-hails comprised roughly half of the increase in traffic congestion citywide, the transportation authority also noted ride-hail rides account for 25 percent of total vehicle congestion citywide, and about 36 percent of all traffic congestion in the downtown core of The City.

While Uber and Lyft keep their traffic data close to the vest, the transportation authority researchers plan to allow public access to the bulk of their research for public vetting. The transportation authority is also releasing a new interactive online map Tuesday to let the public dial down on specific San Francisco streets to see just how bad the traffic gets at any particular intersection, and if that intersection is more affected by Uber and Lyft or job and population growth.

That map reveals Uber and Lyf- related traffic woes look even worse in certain neighborhoods and at certain times.

Eastern neighborhoods largely bear the brunt of ride-hail related traffic congestion: Downtown, South of Market, Mission Bay and other District 6 neighborhoods saw a 12,000 hour increase in the average daily hourly delays from 2010 to 2016, half of which was attributable to ride-hails, the other half attributed to a mixture of new jobs and population boom.

To understand this measurement, if every vehicle experienced an hour of delay, for instance, and 12,000 vehicles drove through that neighborhood, that would equal 12,000 hours of vehicle delays.

Ride-hails comprised about 15 percent of all vehicle trips taken within San Francisco in 2016, according to the SFCTA.

Though you would expect downtown to be affected by ride-hails, other less obvious neighborhoods were impacted disproportionately by ride-hails, including North Beach and other District 3 neighborhoods, with Uber and Lyft causing a whopping 70 percent increase in traffic congestion there.

Specific intersections — especially key choke points near the entrances to the Bay Bridge and other major arteries — also see widely different effects from Uber and Lyft.

Drivers rolling up Bryant Street toward the Bay Bridge, where traffic congestion has doubled, can thank Uber and Lyft for about 80 percent of that. The Marina District’s congestion also spiked, with traffic slowdowns on westbound Lombard Street near Van Ness Avenue attributable to the ride-hails, right on the approach to the Golden Gate Bridge.

City and state officials’s responses to the study were across the map.

Supervisor Aaron Peskin, who also chairs the transportation authority, said the report “underscores the importance of our current collaborations with (ride-hails) to develop a per-trip tax to help mitigate the impacts of these trips, and informs our efforts to balance the availability of these new mobility options with our transit first policies.”

State Senator Scott Wiener, a vocal defender of ride-hail companies who also has supported regulations for them, including a potential new tax on ride-hail companies, said he feared San Franciscans would turn to Uber and Lyft as “scapegoats.”

“I am seeing study after study which appear to be a basis to dramatically scale back ride-hails and turn them into taxi cabs,” Wiener told the San Francisco Examiner. “We saw how that went with our cab industry not providing a level of service the public needed.”

However, Castiglione, the researcher from the transportation authority, noted there are no “asks” coming from the report. Staff members will present it to the transportation authority board, which is also the Board of Supervisors, at its regular Tuesday morning meeting.

“There’s a lot of hypotheses” out there about traffic, Castiglione told reporters. “But we are trying to do real analysis, and ground it in data and rigor.”

A color-coded map shows the percentage increase in traffic delays, measured in daily hours of vehicles along the traffic corridor signified, across San Francisco. The darker the line, the worse traffic congestion created by Uber and Lyft is. (A color-coded map shows the percentage increase in traffic delays, measured in daily hours of vehicles along the traffic corridor signified, across San Francisco. (San Francisco County Transportation Authority)
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