But less lanes means more traffic?
This is a myth. By giving people more alternative modes of transportation, this will take cars off the road which means less traffic.
Resources
Why Car-Free Streets May Be Here to Stay - YouTube - Bloomberg Quicktake
https://www.youtube.com/watch?v=b2HvW2iGNRk
There is a segment where people are complaining that removing cars from Market Street would be bad but the data shown is different. You can see it at 5:53. There was no negative impact for travel times but bus times increased.