Study: Ride-Hailing Intensified Traffic Woes in San Francisco

The proliferation of ride-hailing services such as Uber and Lyft nearly tripled traffic delays in San Francisco from 2010 to 2016, according to a new study.

Researchers from the University of Kentucky and the San Francisco County Transportation Authority conducted the study using data from ride-hailing companies and Inrix Inc., a traffic-mapping and connected-car services supplier. The findings are published in the journal Science Advances.

The researchers say weekday vehicle hours of delay increased by 62% from 2010, when so-called transportation network companies (TNCs) were launching their services, to 2016. Without TNCs, traffic would have grown by 22% during this period, according to the study. Average vehicle speeds in San Francisco fell more than 4 mph to about 22 mph from 2010 to 2016.

Congestion patterns on San Francisco streets can be viewed online HERE.

The study takes into account other contributing factors, such as population, employment and mass transit. For example, the population increased by 9% over the study period, while employment soared by 29%. The researchers say TNCs still were the biggest contributor to the increased traffic.

In 2016, TNCs accounted for 15% of all intra-San Francisco vehicle trips, 12 times as many made by traditional taxis. Car ownership in the city increased slightly, growing from 1.08 vehicles per household in 2010 to 1.1 in 2016. Rail ridership grew substantially over this period, while bus ridership slipped sllightly.

The authors attribute TNC-induced traffic delays to several factors. These include “deadhead” miles—waiting for and traveling to pick up passengers or returning empty—and greater congestion at pick-up/drop-off areas. Deadheading is said to account for as much as 20% of a ride-hailing vehicle’s miles in San Francisco.

If ride-hailing hadn’t existed, the study estimates, more than 40% of trips either wouldn’t have been made at all, or users would have walked or biked to their destination. The authors didn’t take into account the benefits of multi-passenger trips, which they note can account for as much as 20% of ride-hailing trips.

Ride-hailing services also could increase the use of some mass transit systems by providing first-mile/last-mile to local stations, according to the study. The authors also speculate that TNCs could eventually reduce vehicle ownership rates and, in turn, reduce overall vehicle miles traveled.