​On March 25, 1998, Trooper Armstead, 27 years old and a 14-month veteran of the Maryland State Police, was operating his patrol vehicle northbound on I-295, south of Powder Mill Road in Prince George's County when he observed someone on the shoulder of the road waving their arms for assistance.  Realizing there had been an accident, Trooper Armstead attempted to cross the lanes of traffic to assist the stranded motorists.  As Trooper Armstead focused on the shoulder activity, the traffic ahead of him stopped.  Trooper Armstead's patrol car collided with a van that was stopped in front of him causing him to become trapped in his vehicle for approximately 30 minutes.  Once extracted, Trooper Armstead was flown to the Shock Trauma Center in Baltimore where he was pronounced dead shortly before 3 p.m.​