I don't think the effect has been definitively proven one way or the other. While there are studies showing a decrease in congestion, there are also several showing a notable increase too[0][1].
I can say, anecdotally, in SF there are lots of Uber/Lyft drivers who drive in from outside of the city (and even Bay Area) because they can make more driving in the city. If they disappeared, would they be replaced by an equal or greater number of private cars? Given the parking situation in SF, I doubt it, but who can say.
I can say, anecdotally, in SF there are lots of Uber/Lyft drivers who drive in from outside of the city (and even Bay Area) because they can make more driving in the city. If they disappeared, would they be replaced by an equal or greater number of private cars? Given the parking situation in SF, I doubt it, but who can say.
[0]https://www.sfexaminer.com/news/study-half-of-sfs-increase-i... [1]http://www.schallerconsult.com/rideservices/automobility.pdf