The blue lights are there as a visual sign to police officers on side roads when the traffic signal on crossing roads is "red." From their slidelong vantage point, even at a long distance, they can see that somebody on a cross road has driven through a red traffic signal. They cannot see the red light because it is facing the two crossways directions, but they can see the blue light. If they see you drive under a blue light, they know you have committed a traffic infraction.
As an added bonus to you, the blue light serve to help you sort out the traffic signals from the thousands of other red colored lights that adorn the sides of the roads and highways.
|