Original sentence: Compared to GPS systems, the cost difference may or may not be significant, as the single expense of the GPS primary application hardware and software comprises the bulk of the expense, which decreases per vehicle as more vehicles are added to the system.Compared to line-of-sight systems, the cost difference between a simple strobe light or infrared emitter, and the cost of the localized radio system's transmitter and control box (especially if it includes extra capabilities such as collision avoidance) is significant.Drawbacks of localized radio signal include cost and undesired activations.In addition, at a very high power setting, other intersections very close by but not in the visual line-of-sight path of the emergency vehicle may potentially be activated.Undesired activations may occur if an emitter is inadvertantly set to a high power setting and is picked up by many traffic lights along a stretch of road, all directed to change to green in that direction, prior to the activating vehicle turning off the road early or being parked without its emitter being deactivated