If a rogue uses an action to Dash and then Cunning Action to Dash, do they move 90 ft. or 120 ft.?

@mikemearls If a human rogue uses an action to Dash (60 ft.) and then Cunning Action to Dash, do they move 90 ft. or 120 ft.?

— Sam Stockdale (@BitterChivalry) July 31, 2017

That's correct. Dash doesn't increase your speed.

— Jeremy Crawford (@JeremyECrawford) September 18, 2017