Both Bailey and Brooke have been or are terrified of situations like this. (Bailey is deceased now but we had to do the same thing for both of them) and our neighbourhood isn't near as busy. We had to gradually desensitize them to the noise and hustle and bustle of people. We took them with us to places like the farmers market nearby on less busy days and just walked with them, no shopping, just walking and if their fear escalated too much, we'd leave. But gradually they got used to it, not 100%, but still a huge improvement.
I find when we are doing touristy things, Brooke still hides behind me and I ask people to leave her alone so as to not heighten her fear. But she's improved a lot. I do this when walking Iker too.