Patent ID: 7663504

Claim:
A method of warning a driver within a first vehicle of an emergency vehicle proximate said first vehicle, the method comprising the steps: generating a Vehicle Present Signal from outside the first vehicle; receiving said Vehicle Present Signal by a receiver within said first vehicle; determining, from the Vehicle Present Signal, a distance between said emergency vehicle and said first vehicle; activating a warning system within the first vehicle to an on-state if the distance is less than or equal to a first predetermined distance; and, governing the warning system by a governing circuit that includes a dead band defined by upper and lower limits respectively corresponding to the first predetermined distance and a second predetermined distance greater than the first predetermined distance, the step of governing the warning system including the step of preventing the warning system from cycling from the on-state to an off-state when a distance between the first vehicle and the emergency vehicle transitions from a distance less than or equal to the first predetermined distance to a distance within the dead band greater than the first predetermined distance.