I always believed that the blue lights were connected in some way to oncoming Emergency Vehicles. But I did a little research and came up with a couple answers...
Answer #1
quote from ask.com
Those blue LED's are signal markers. Basically, whenever an emergency vehicle needs to run a red light or cross over some railroad tracks, they initiate a signal beacon on their vehicle (example being the strobe light on the front center of a fire engine). This beacon hits a receiver on the traffic light, and starts a process to change the light from red to green. The blue LED is a way for the emergency personnel to tell whether or not the traffic light is going to change, or has already changed. If the blue light is on, the light is red, if it is out then the light is green. If it is blinking then it is going to change from red to green really quick! The funny thing about this is that most city buses have the same transmitter as the cops or emergency vehicles, that way they can make sure to stay on their time schedule.
Answer #2
quote from Solutions for LED Lights.com
Blue lights above traffic signals on state roads verify traffic violations
By Carolyn on June 29, 2008 2:10 PM | Permalink
According to the Federal Highway Administration, in 2000 there were 106,000 crashes from running RED LIGHTS, with 89,000 injuries and 1,036 deaths.
Blue lights above traffic signals are called "tattletale lights" or "red light confirmation lights." Whenever the traffic signal is red, the blue light is on.
Police previously had to testify that a vehicle was in an intersection when it ran a red light.
Now, officers only have to see the blue light to know the vehicle ran the red signal.
Running a red light in Florida can bring a fine of $188.50.
Violators also face adding three or four points to their driving record, unless they complete a state-approved driver-safety course.
The Orlando Sentinel confirms the second answer to be true. So I guess I learned something too.
