Uber, Lyft responsible for half of growth in SF traffic, study says

SAN FRANCISCO » Uber, Lyft and services like them contributed to half of the growth in traffic in San Francisco over a six-year period, according to a report released Tuesday — but transportation experts say the full story is a lot more complicated.

Between 2010 and 2016, traffic increased dramatically: The average speeds in San Francisco slowed by around 26 percent, the number of hours people spent crawling along at those low speeds grew by around 40,000 hours, and the total number of miles people traveled increased by 630,000 miles on a typical weekday, according to the report from the San Francisco County Transportation Authority (SFCTA).

But, even though anecdotally, people felt some of that traffic may be a result of Uber, Lyft and similar ride-hailing services, the companies have been reluctant to share their data with cities and other public agencies, said Joe Castiglione, the transportation authority’s deputy director of technology, data and analysis and the author of the report. So, there was no way to quantify the impact of those new services. (In California, the Public Utilities Commission collects data from Uber and Lyft and ride-hailing services, but has so far declined to share it, he said.)

So, Castiglione, along with researchers from the University of Kentucky, used data that computer scientists from Bostonbased Northeastern University were able to gather from Uber and Lyft, including data specific to San Francisco. They combined it with commercial data from INRIX, a company that specializes in big data sets and annually produces a global congestion report, along with data collected from changes in bike and transit lanes and population and employment data.

And, what they found wasn’t all that surprising, Castiglione said: Ride-hailing services contributed to the growth in traffic congestion. What was surprising, he said, was how much. The report found ride-hailing services contributed a whopping 55 percent to declining speeds, 51 percent to the growth in the amount of time people spend sitting in traffic and 47 percent to the increase in miles traveled over the six-year period.

But, not all parts of the city were affected equally. Ride-hailing services impacted the city’s downtown core much more than neighborhoods in the western and southern parts of the city, and they contributed more to nighttime traffic congestion than the morning commute, according to the report.

“This is the first instance when someone has actually been able to put a number on this,” he said. “And, because it was such a significant share we put it through quite a bit of scrutiny.”

Both Lyft and Uber rejected the findings — saying the researchers didn’t take into account other factors, including the growth in tourism and deliveries, or the ways that rising incomes change people’s travel and spending habits. There wasn’t good data on new delivery services, such as UberEats, Castiglione said, but the report did account for the growth in tourism and commercial vehicles.

Transportation experts, however, sided with Uber and Lyft. There was significant economic growth between 2010 and 2016, said Elliot Martin, a research and development engineer at UC Berkeley’s Transportation Sustainability Research Center. And, while the study does factor in population and employment growth as contributing the other half of worsening traffic, Martin said those two variables alone may be oversimplifying the equation.

“It’s hard to disentangle all these impacts together,” he said. “You’re talking about a period of time when there was tremendous changes taking place in the city.”

Nor is it productive to play the “blame game,” said Gerry Tierney, an associate principal at the architecture and design firm, Perkins+Will. If ride-hailing services such as Uber and Lyft weren’t providing a better experience than traditional forms of transit, people wouldn’t be paying for them, he said.

“These services are responding to a real demand,” he said.

And, for their part, both Uber and Lyft said they were hoping to be part of whatever solutions the SFCTA wants to employ. Traffic congestion isn’t good for either company, their representatives said. And, both have been implementing new services, some of which have only rolled out recently, to reduce people’s dependence on cars.

Earlier this year, Uber launched its ExpressPool service, which uses a fixed route and requires people to walk a few blocks to designated pick-up spots to more efficiently ferry people around the city. And, both companies bought bikesharing services they say will help reduce car trips.

Uber representatives said the company is already working with San Francisco to generate dedicated funding for public transit and is ready to help the city with other traffic-busting solutions, like creating transitonly travel lanes, increasing the adoption of bicycling and placing limits on car travel. Representatives from Lyft suggested introducing congestion pricing and building more housing near transit to reduce traffic.

“Our whole mission statement … is all about giving people options to get where they are going in a safe and reliable fashion,” said Lauren Alexander, a spokeswoman for Lyft. “We understand there are pain points, and we definitely want to be part of the solution.”