What racial injustices does Troy see and/or describe in the first act of Fences?

On many levels, Troy is a product and eyewitness to racial
injustices.  On the most basic of levels, Troy understands that there is a sense of
discrimination at his workplace in his complaint that only the white workers are allowed
to drive the truck.  This is significant on a couple of levels.  The first is that it
shows that Troy is sensitive to the issue of race.  However, on another level, it shows
that Troy can only identify the immediate issue of racial discrimination on the most
immediate of levels.  He is unable to see past his own struggle and advocate for a
broader and more sociological discussion and transformation of racial identity.  He sees
racism as something that impacts only him, causing a type of intellectual and emotional
"fence" to be constructed between himself and others, precluding solidarity.  In scene
iii, Troy declares that he simply exists, "moving from one Friday night to another." 
This might be another example of racial injustice, to a certain extent.  Coming on the
heels of Troy's own exploration as to why his dreams were denied by sociological reality
and that he willfully admits that he wants his so to do better than he has fared in his
own life, Troy's statement of existence might be connected to the fact that he perceives
race as having much to do with why he has not resulted as more or with more in his state
of being in the world.  The entire confrontation between father and son is also fostered
by what the father perceives to be racial injustice.  Troy does not want his son to
endure the same obstacles and heartbreak that he suffered with his own dreams, something
that he perceives was a construct of race in America.  The presence of racial injustice
is both seen and felt in Troy's life, which is both a product of racial injustice but
also of the inability to transcend difficulty in being and consciousness in the
world.