When we came from Naples, Italy where I was born to Atlanta in 1957 and then to Augusta in 1960, my Tuscana mother did not drive, so my dad made sure we lived very near a city bus stop. Thus I remember riding the bus with my mom to shop in downtown Atlanta and Augusta and what seem to me to be everyday!
And this is exactly what I saw! Please note the sign for where the white section is. That sign was movable and only the bus driver could push it backwards if there were more whites on the bus or forward if fewer whites. Other buses though had a painted line on the floor with whites on one side and blacks on the other!
I also rode the bus to the movies with my friends by ourselves once we turned 12, yes this was another planet! As we got near our homes from returning from the movies, the bus was empty with just my two friends and me and we ran to the back of the bus to sit on the bus-wide back seat, what we called the funny seat since the bounce over road bumps was the most pronounced!
The bus driver laughed and shouted back at us, "who do ya'll think you are, "n..s?" Yes whites called each other "n...s" as well! And when I worked at the Dairy Queen Brazier from about 1968 to 72, and our employer finally integrated the employees, I was quite shocked to here my black friends call each other the "n" word and when I expressed shock, they told me it was quite common, but they could do it, but not whites.
Finally I remember a brave young white woman sneak to move the white sign forward while the bus driver was distracted so an overweight and sweating elderly black woman could sit down! Bless both their hearts! You can imagine how hot our unconditioned buses got in our over 100 degree summer days!