Simple RAW for 5e V: The Disadvantage Strikes Back

[E’Tallitnics]

Q90

A rogue/battlemaster uses evasive maneuver to up their A.C..

Move 30ft, Action dash 30 ft, action surge dash 30ft and use a bonus action for cunning action BA to dash 30ft.

Do this warrior get the A.C. bonus for the entire 120ft?

A90: You bet! With the caveat that “Evasive Footwork” grants the bonus to AC from your superiority die until you stop moving, not just for the amount of speed that you have that round.

Taking the Dash action just adds to the speed you have, and moving uses up that speed.