Forensic Engineering Analysis of the Alleged Failure of an Emergency Vehicle Traffic Light Preemption System

Abstract

This case involved a fatal collision between a police vehicle (operated by a police officer) and a non-police vehicle (operated by a civilian). With lights and sirens activated, the officer in pursuit ran a red light and crashed into the civilian’s vehicle in an intersection whose traffic light controller included an emergency vehicle preemption system. The civilian driver was mortally injured, and died the next day. The estate of the deceased driver sued the police officer, municipal police department, and manufacturer of the emergency vehicle preemption system. The author was retained by counsel for the estate of the deceased to assist in the case against the manufacturer of the emergency vehicle preemption system and municipality. The evidence showed that the preemption system was working properly, but that the system’s confirmation lights had been improperly programmed. A maximum speed was calculated at which a preempted green light for emergency drivers would be assured. Event logs in the police vehicle showed that the police officer was driving too fast for the traffic light controller to cycle through its sequence before the officer reached the intersection.