Myrtle Beach, SC

I spent 6 weeks last year in Myrtle Beach, SC with the Radio City Rockettes. I always laugh at the street names Mr. Joe White Ave. Why the Mr.? The street that goes to the Myrtle Beach airport is (Dr. W. LeRoy) Harrelson Blvd. What is up with the parenthesis and the Dr.? I guess it is just the South.