# Floridians: What's that blue light on traffic signals? **URL:** \ **Category:** Factual Questions\ **Created:** [February 17, 2013, 8:26pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619 "2013-02-17T20:26:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![jebert](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@jebert](https://boards.straightdope.com/u/jebert)\ **Post date:** [February 17, 2013, 8:26pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/1 "2013-02-17T20:26:21Z")
I recently traveled to Florida - Ft. Myers area specifically. I noticed several intersections where there was a small blue light at the bottom of one of the traffic signals hanging over the intersection. I also noticed that the blue light turned off when the signal changed to green. Can any of you Floridians explain what this blue light is for? ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [February 17, 2013, 8:49pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/2 "2013-02-17T20:49:08Z")
> [@jebert](#): > > I recently traveled to Florida - Ft. Myers area specifically. I noticed several intersections where there was a small blue light at the bottom of one of the traffic signals hanging over the intersection. I also noticed that the blue light turned off when the signal changed to green. > > Can any of you Floridians explain what this blue light is for? I’m on the other coast of Florida, and apparently we do things differently here. I’ve don’t believe I’ve every seen a blue light on a traffic signal like that. Sorry. That being said - this [forum](http://www.aaroads.com/forum/index.php?topic=4918.0) claims they are “rat” lights. They apparently are used to indicate when the light is red, to aid police. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [February 17, 2013, 9:37pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/3 "2013-02-17T21:37:43Z")
When will people learn that Google long ago became the all-knowing Matrix?! 😃 Just put in _‘blue light on traffic signals’_, [and got this!](http://www.ekday.com/2008/08/24/blue-lights-on-orlando-traffic-lights-mystery-sloved/) ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [February 17, 2013, 10:31pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/4 "2013-02-17T22:31:27Z")
> [@Digital\_is\_the\_new\_Analog](#): > > They apparently are used to indicate when the light is red, to aid police. Which is fine, but maybe people wouldn’t run lights so much in Florida if they didn’t stay red so gawddam long! I timed one in Sarasota at 4 minutes 30 seconds!:eek: WTF? ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [February 17, 2013, 10:44pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/5 "2013-02-17T22:44:27Z")
> [@pkbites](#): > > Which is fine, but maybe people wouldn’t run lights so much in Florida if they didn’t stay red so gawddam long! I timed one in Sarasota at 4 minutes 30 seconds!:eek: WTF? Na. Floridians will still run them. Sometimes it seems we deliberately don’t synchronize our lights just so there are more red lights to run. ---
**Author:** ![Bob\_X](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@Bob\_X](https://boards.straightdope.com/u/Bob_X)\ **Post date:** [February 18, 2013, 4:53am UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/6 "2013-02-18T04:53:46Z")
The blue light means that the blue-hairs can go. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [February 18, 2013, 8:22am UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/7 "2013-02-18T08:22:13Z")
I have seen little blue lights something like this in Simi Valley (southern Calif.), several years ago. They aren’t below or above the signal, but on the back side of them. I guessed then that they were to help cops tell, even seeing a signal from behind, when they are red. Calif. is also the land of the [metered freeway on-ramps](http://www.mtc.ca.gov/news/congestion/ramp_meter_photos/I-580/8863D_049.JPG). Most of these also have a light facing the back side, so a cop can park ahead a ways, and see when the light is red. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [February 18, 2013, 9:12am UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/8 "2013-02-18T09:12:08Z")
> [@Senegoid](#): > > I have seen little blue lights something like this in Simi Valley (southern Calif.), several years ago. They aren’t below or above the signal, but on the back side of them. I guessed then that they were to help cops tell, even seeing a signal from behind, when they are red.. They’re here in Northern California as well. It seems they’re more common on the lights mounted lower on the side of the road (as compared to ones on the overhead pole). ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [February 18, 2013, 9:13am UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/9 "2013-02-18T09:13:28Z")
Call me crazy, but to my thinking the best way to tell a red light is on is that you can see a red light. I don’t get how sticking a blue light under it makes any difference at all. ---
**Author:** ![Alley\_Dweller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alley_dweller/32/430_2.png) [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)\ **Post date:** [February 18, 2013, 9:46am UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/10 "2013-02-18T09:46:13Z")
> [@Johanna](#): > > Call me crazy, but to my thinking the best way to tell a red light is on is that you can see a red light. I don’t get how sticking a blue light under it makes any difference at all. Certainly if you are facing the same direction as the light. But sometimes traffic going one way has a longer red/green than traffic going the other way. If you are facing the other way, you would not be able to see whether oncoming traffic has a red or green. And if you are approaching the intersection from the cross-street, you may not be able to see the traffic light for the traffic traveling perpendicular to your street at all. ---
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [February 18, 2013, 1:02pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/11 "2013-02-18T13:02:34Z")
> [@Alley\_Dweller](#): > > If you are facing the other way, you would not be able to see whether oncoming traffic has a red or green. > > And if you are approaching the intersection from the cross-street, you may not be able to see the traffic light for the traffic traveling perpendicular to your street at all. So are these blue lights intended _only_ for the police? Or are they useful to all drivers? And–a related question: If they are intended only to help the cops—why not use cameras, instead of little blue lights? Cameras are dirt cheap these days. You could probably mount a camera on every single traffic light, including an auto-focusing device and a wi-fi hookup, for about the price of 3 or 4 traffic fines. Thereafter…it’s free money for the city. Is Big Brother on the way?and if not, why not? ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [February 18, 2013, 1:07pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/12 "2013-02-18T13:07:40Z")
Call me silly, but I’d think a camera would have the light-jumber end up with a ticket later on. Now, if a cop sees the jumper jump a light, then he’ll get a ticket (or at least a warning) and perhaps not jump more red lights that day. ---
**Author:** ![MilTan](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@MilTan](https://boards.straightdope.com/u/MilTan)\ **Post date:** [February 18, 2013, 1:13pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/13 "2013-02-18T13:13:58Z")
> [@Monty](#): > > Call me silly, but I’d think a camera would have the light-jumber end up with a ticket later on. Now, if a cop sees the jumper jump a light, then he’ll get a ticket (or at least a warning) and perhaps not jump more red lights that day. Also, the revenue proposition is a little different for cops’ catching light-runners (where the revenue goes straight to the department) than for traffic cameras’ doing the same (where the bulk of the revenue goes to the camera operator, not the department). ---
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [February 18, 2013, 1:41pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/14 "2013-02-18T13:41:14Z")
> [@MilTan](#): > > Also, the revenue proposition is a little different for cops’ catching light-runners (where the revenue goes straight to the department) than for traffic cameras’ doing the same (where the bulk of the revenue goes to the camera operator, not the department). You’re saying that there really is a good source of revenue here. So why doesn’t the city open a “camera operator” department? (just like they have a department of building inspectors, and health inspectors). Are there technical problems make it unfeasible? Not that I want to have cameras everywhere…but if there’s a way to take money from people, eventually somebody’s gonna do it…either private or government. Why hasn’t it happened yet? ---
**Author:** ![crucible](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@crucible](https://boards.straightdope.com/u/crucible)\ **Post date:** [February 18, 2013, 1:48pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/15 "2013-02-18T13:48:47Z")
so, no one really knows what the blue lights are for. Quote What are the tiny blue lights on the backside of the stoplights?-Steve Clelland Stoplights are a simple concept - green means go, yellow means slow down and red means stop. But blue? Blue could result in a ticket and a fine. _Remaining text removed by moderator. You may read it on the original site (KTVB News) [here](http://www.ktvb.com/news/local/64291897.html)._ ---
**Author:** ![crucible](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@crucible](https://boards.straightdope.com/u/crucible)\ **Post date:** [February 18, 2013, 1:54pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/16 "2013-02-18T13:54:42Z")
I have seen screwed up lights in Florida, esp. where the size of the road is large, multi-lanes, and they split out the left turn lane or lanes such that they are not right next to the lanes continuing straight ahead…then they give the left turn lanes a green light instead of a green arrow. The green light does not mean you have the right of way, but a driver might not understand that and could pull directly into oncoming traffic. hard to explain until you are there and confused whether you should go, or not. ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [February 18, 2013, 2:56pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/17 "2013-02-18T14:56:14Z")
> [@Monty](#): > > Call me silly, but I’d think a camera would have the light-jumber end up with a ticket later on. Now, if a cop sees the jumper jump a light, then he’ll get a ticket (or at least a warning) and perhaps not jump more red lights that day. People running red lights are also probably disproportionally likely to be committing other crimes as well (driving without a license or with a suspended license, driving drunk, driving at night with a graduated license, fleeing another crime, etc.). I live in a college town, and I notice the cops station a car near the intersection leading away from the bars around closing time, I presume to snap up all the plastered students who fly through the red light. ---
**Author:** ![April\_R](https://avatars.discourse-cdn.com/v4/letter/a/3da27b/32.png) [@April\_R](https://boards.straightdope.com/u/April_R)\ **Post date:** [February 18, 2013, 3:02pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/18 "2013-02-18T15:02:15Z")
In Memphis the Blue Light means there is a traffic cam at that particular intersection and if you run the light you will get a nifty invite form the local police department. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [February 18, 2013, 3:17pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/19 "2013-02-18T15:17:21Z")
One reason for the blue lights instead of traffic cams is that a lot of residents fight the installation of traffic cams as being problematic and prone to error. The local paper that I read this in is, in fact, the _Fort Myers News Press_, the location mentioned in the OP. The blue light synced with the red light gets around the reliability issue because it’s just a visual cue to help police officers. Therefore, it becomes a matter of the cops witnessing the crime personally, which already has plenty of precendent. **Jebert** , you should have told me you were coming. I’d have bought a cake. ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [February 18, 2013, 4:15pm UTC](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619/20 "2013-02-18T16:15:40Z")
> [@pkbites](#): > > Which is fine, but maybe people wouldn’t run lights so much in Florida if they didn’t stay red so gawddam long! I timed one in Sarasota at 4 minutes 30 seconds!:eek: WTF? I am absolutely convinced there are people in Florida that will not stop at ANY red light unless there is a car already stopped in front of them. Annd once I got the finger as a guy zipped around me to run one I had just stopped at. [Next page](https://boards.straightdope.com/t/floridians-whats-that-blue-light-on-traffic-signals/650619.md?page=2)