Uber and Lyft Causing Road Congestion in San Francisco

The rapid growth of TNCs (Transportation network companies) is attributable to the numerous advantages and conveniences that TNCs provide over other modes of transportation, including point-to-point service, ease of reserving rides, shorter wait times, lower fares (relative to taxis), ease of payment, and real-time communication with drivers. The availability of this new travel alternative provides improved mobility for some San Francisco residents, workers and visitors, who make over one million TNC trips in San Francisco every week, though these TNC trips may conflict with other City goals and policies. The purpose of this research is to identify the extent to which TNCs contributed to increased roadway congestion in San Francisco between 2010 and  2016, relative to other potential contributing factors including employment growth, population growth, and changes to the transportation system.

This research showed that San Francisco's road congestion significantly worsened between 2010 and 2016. Based on monitoring data from the SF Transportation Authority's Congestion Management Program, peak arterial speeds decreased by 26% for morning commutes, and by 27% in the evening. On a typical weekday, total vehicle hours of delay increased by 40,000 hours, and vehicle miles traveled increased by over 630,000 miles. Transportation network companies (TNCs) accounted for approximately 50% of the change in congestion in San Francisco between 2010 and 2016, as indicated by three congestion measures: vehicle hours of delay, vehicle miles traveled, and average speeds. Employment and population growth—encompassing citywide non-TNC driving activity by residents, local and regional workers, and visitors—are primarily responsible for the remainder of the change in congestion.

In this study, TNC  information  was  based  on  data  originally  gathered  by  researchers  at  Northeastern  University  from  the  Application  Programming  Interfaces  (APIs)  of  Uber  and  Lyft  that  show  the  locations  of  available  vehicles  to  mobile  apps,  and  then  was  shared  with  the  Transportation  Authority.    The  data  was  collected  from  mid-November  to  mid-December  of  2016,  excluding dates around the Thanksgiving 2016 holiday.  Transportation Authority staff then processed the data to impute estimates of out-of-service TNC volumes, in-service volumes, and pickups and dropoffs by directional link and time-of-day.  This information was the basis for the TNCs Today, which is the only detailed profile of local TNC usage in San Francisco.

Given the significant worsening of congestion in San Francisco in recent years, a critical question is whether, and to what degree, TNCs have affected congestion. Using the congestion measures, data, and methods previously described, it appears that TNCs contributed approximately 50% of the overall increases in congestion in San Francisco between 2010 and 2016, although this varies widely by neighborhood and time-of-day.  Employment and population growth—an expression of greater economic activity in the city that encompasses the driving activity of all non-TNC travelers/motorists—account for the other half of the increase in congestion.


San Francisco County Transportation Authority. (2018, October). TNCs and Congestion. San Francisco, CA. Retrieved from

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