[Captain Obvious]

man its easy to read what coverage the D is in..

safeties go wide, cover 2 man or zone, and even then you know the difference ( against zone, attack the mid, man, lol anything)

1 safety goes high and the other low, some type of cover 3.
(curls or corners, posts if your quick)

all DBS go back, cover 4
(underneath routes, again curls or crosses and slants)

always read the safeties first, then the linebackers. you can determine what theyre in in a second flat