LAS VEGAS - A viewer asks what the purpose is of bright blue lights on traffic signal poles.
That blue mystery light is an indicator that helps police catch drivers who run red lights. A police officer typically waits in a safe location near the intersection, where he or she can observe the blue light.
When the red traffic signal arrives, the blue light turns on. The officer can then determine if a driver entered the intersection on the red. A big benefit is police can tell whether cars are running red lights from either side of the intersection.
Most intersections include white lines or stop bars. When a vehicle crosses that line on a green or yellow light, it claims the right-of-way in the intersection. Drivers are following the law as long as they safely enter the intersection on a green or yellow and, therefore, can safely exit the intersection (even on a red light) without breaking the law.
If the light is yellow before the vehicle reaches the stop bar, stop line, or crosswalk, the driver must reduce speed and prepare to stop. Running a red light can result in a ticket of $300 or more.
Police have a number of ways to nab red light runners, including these blue indicator lights.
What's driving you crazy? E-mail your traffic questions and complaints to Brian Loftus.