A man and woman who are suspected of robbing banks in Arlington and Waltham were arrested after they fled from police in a stolen car, State Police said today.

State Police stopped Andrea Koutis, 30, of Arlington, and Erik Stout, 35, of Somerville, for erratic driving at 4:54 p.m. Tuesday, less than an hour after the two allegedly robbed the East Cambridge Savings Bank in Arlington and Sovereign Bank in Waltham, State Police said in a statement.