Does he resond to treats well ?
When Cheyanne was younger i socalized her in diffent places
with treats She's a very shy and timid dog anyway so i wanted to get her used to diffent places as best as i could.

I would try going to parking lots and doing some commands with her on the pavement maybe she will not think so much about the pavement and relize it's nothing to be afaid of.

I brought Cheyanne in the pet stores like 1 or 2x a week so she could get use to all diffent people and smells and ect. that seemed to work pretty good. It took only about a month before she did'nt care about what people walked by and just went for the good doggy isles. Now she just walks by people unless they come to pat her then there's doggy kisses coming there way

Good luck i hope this helps