Ride sharing companies such as Uber, Didi and Lyft have resulted in a massive increase in road congestion, according to a new study now underway.
Such firms, becoming known as Transport Network Companies (TNCs), accounted for about 50 per cent of the increased congestion in San Fransisco between 2010 and 2016.
This was after taking account of employment and population growth and network capacity shifts (such as for a bus or bicycle lane).
The study, TNCs & Congestion, is being undertaken by the San Francisco County Transportation Authority and the University of Kentucky.
It found that the services are responsible for more than 40 per cent of the additional impact in the morning and afternoon peaks.
Interestingly ride sharing massively increases traffic in the evenings, being responsible for more than 60 per cent of the increased travel.
And it calculates that the vehicles were responsible for 25 per cent of the total delay on San Francisco roadways and about 36 per cent of total delay in the downtown core in 2016.
The report says TNCs have grown because they offer advantages to travellers 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.
"If all TNC trips simply replace private vehicle trips, then TNC trips may have a limited impact on roadway congestion. But if TNC trips replace walk, bike, and transit trips, or if they induce entirely new vehicle trips, TNC trips may have a more significant effect on congestion.”
San Francisco County is embarking on a number of further investigations into the impact on ride sharing, including impacts on street safety and bike riders, public transport, trip generation, land use and parking, disability access, and equity across the community.