Abstract: A traffic entity, such as a passenger car, is warned that a situation requiring the change of driving mode will be required. The traffic entity is alerted to the presence of a second traffic entity, such as an emergency vehicle which requires the moving traffic entity to change its movement when it is proximate to the second traffic entity. The alert is changed, such as by increasing the intensity of visible signals, as the distance between the moving traffic entity and the second traffic entity decreases or the closing speed between the two entities increases, and the mode of the alert is changed, such as from visible to audible, as the distance between the entities further decreases or the closing speed further increases. A variety of traffic entities are accommodated by the system.