Blue Tattletale lights (specifications, standards, officiality?)

[Dustin DeWinn]

I don't see this discussed much, and not on this child board (at least by the terms that I searched for), but I wanted to talk about the blue tattetale lights for red-light runners.

Are these standardized across jurisdictions?
In another thread, someone asked for what wavelength of light (exact color) traffic lights use. Do these tattletales use the same frequency of light?
Are these part of the MUTCD? How are they regulated? - I mean in design, functionality, appearance, etc.

At some point I'd also like to discuss the blue light emergency phones (same questions basically) but that's not traffic related. 

[Dustin DeWinn]

I meant these : https://i.redd.it/pnl2ix1qojq21.jpg

Are they the same. The seem to be above the mast: https://i.ytimg.com/vi/gyAtcvsIyZc/maxresdefault.jpg
and
https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQ3KDf50uB6lwauquzcZbGr5NUvctATp1Q4Xw&usqp=CAU



Actually heres a DOT report on them: https://www.fhwa.dot.gov/publications/research/safety/17077/17077.pdf

[Scott5114]

These are also referred to as "rat lights". There are no standard for these in the MUTCD (indeed, in the FHWA report you linked, they noted that because they are not devices intended to control traffic, they are out of the scope of the MUTCD). Whether they're even used or not varies a lot from municipality to municipality, even in the same state. I only know of one that was in use in Norman, and it was removed sometime between April 2015 and May 2016.

[CardInLex]

Lexington, KY uses a different style on the back of some signals. (See backside of left turn signal)

https://goo.gl/maps/j2pQ3Lwjsgw2uTQd7

[TheHighwayMan3561]

A few Twin Cities locations have added these in isolated places. Most of them I've seen are in the north metro in Shoreview and Blaine, but at least one in Minnetonka at MN 7/Williston.

[roadfro]

FYI for the OP: There was a short thread on this topic way back in 2011: https://www.aaroads.com/forum/index.php?topic=4918

[TEG24601]

There doesn't seem to be a standard.  In fact, PBOT, uses them as indicators for bikes that they were detected by the loop sensors, negating their use a tattle-tale lights.

[Brian556]

In Texas, there are white. In Orlando, FL, they are blue

[UCFKnights]

In Texas, there are white. In Orlando, FL, they are blue

Older ones in Orlando (well throughout Florida) are white. They switched to blue for new installations some time ago.

[ari-s-drives]

My first thought was about these rear-facing red signals on ramp meters that I've seen in California, presumably there for police to pull over people running the light (not that I've ever seen that happen)

Here's another instance.

And here is an example of a ramp meter elsewhere in the US without the indicator.

[rarnold]

Meade, Kansas has rat lights at the only stoplight in the county, at the junction of US 54-160 and K-23.

[lepidopteran]

There's something like this in Dayton, OH, at the rather skewed intersection of Far Hills Ave., Oakwood Ave., and Thruston Blvd.  (There's another one on a lone stanchion pole, if you can find it.)  From my observation, the blue light is either flashing, lit steady, or dark, depending upon the phase in the traffic signal sequence.   Never been able to figure out exactly what these are for.

[jakeroot]

From what I've seen:

• Rear-facing 12 or 8 inch reds are reserved for ramp meters. I have never seen one used at a regular traffic light. WSDOT has a couple examples (can't recall where exactly).
• Regular rat lights in my area are tiny little blue LEDs mounted to the bottom of the corner signal on an approach.

As to the lights: I don't get the point. I know they're supposed to be used for ticketing of red-light runners, but (A) is that blue light enough evidence to charge a driver? and (B) how often are they actually utilized for the purpose of ticketing? Because I can think of about a dozen intersections in Lakewood, WA that have these rat lights, and I've not once seen a cop actually using them to ticket people. It would seem to me they are more for circumstantial situations, where a cop just happens to observe a red-light offense while waiting at the intersection themselves. And I say that because I've never seen these intersections built with laybys/turnouts for cops to sit in.

With that in mind, (1) do cops even know what these lights are for? (2) are they actually watching them? and (3) why would they not ticket you for simply running the red light? (A cop should be able to tell what color the light is based on the circumstances of surrounding traffic flow).

[jeffandnicole]

From what I've seen:

• Rear-facing 12 or 8 inch reds are reserved for ramp meters. I have never seen one used at a regular traffic light. WSDOT has a couple examples (can't recall where exactly).
• Regular rat lights in my area are tiny little blue LEDs mounted to the bottom of the corner signal on an approach.

As to the lights: I don't get the point. I know they're supposed to be used for ticketing of red-light runners, but (A) is that blue light enough evidence to charge a driver? and (B) how often are they actually utilized for the purpose of ticketing? Because I can think of about a dozen intersections in Lakewood, WA that have these rat lights, and I've not once seen a cop actually using them to ticket people. It would seem to me they are more for circumstantial situations, where a cop just happens to observe a red-light offense while waiting at the intersection themselves. And I say that because I've never seen these intersections built with laybys/turnouts for cops to sit in.

With that in mind, (1) do cops even know what these lights are for? (2) are they actually watching them? and (3) why would they not ticket you for simply running the red light? (A cop should be able to tell what color the light is based on the circumstances of surrounding traffic flow).

This has been my thinking as well.  Plus, in most cases, the opposing direction will turn red at the same time.  The cross street will have a light or green arrow that turns green a second or two later.  It would appear that there would be significantly more evidence that someone went thru a red light just by looking at the existing lights.

I don't see blue lights all that often in my travels, but when I do, cops haven't been nearby.

[Scott5114]

(3) why would they not ticket you for simply running the red light? (A cop should be able to tell what color the light is based on the circumstances of surrounding traffic flow).

Because this is circumstantial evidence, it could get the ticket thrown out should the driver challenge it in court. Basically, unless a cop can observe both the signal face and the driver passing through it, it can be argued that it cannot be proven beyond a reasonable doubt that the driver actually ran the red light (perhaps the police officer simply did not interpret the traffic flow properly, or a driver on a different leg of the intersection ran the light, or the signals were malfunctioning and displaying conflicting movements).

This means that either (1) the police officer must be upstream of the light and pursue red-light runners through intersection with emergency lights on (dangerous) (2) there have to be two officers, one watching the light and radioing to a second one downstream (costly in terms of labor), or (3) there have to be rat lights.

The rat lights are far better evidence against the driver than observing traffic patterns, because the cop can simply testify they knew the light was red because of the rat light. The driver would then have to prove that the rat light and the signal face were displaying different aspects, which is unlikely.

[jakeroot]

The rat lights are far better evidence against the driver than observing traffic patterns, because the cop can simply testify they knew the light was red because of the rat light. The driver would then have to prove that the rat light and the signal face were displaying different aspects, which is unlikely.

I guess I can see this point, but if circumstantial evidence is worthless, how could the cop actually prove the light was red? He didn't witness it anymore than any other drivers from whichever direction it was observed. The blue light is lit when that light is red, so far as we know, but couldn't a driver simply argue that his light was green and the light was malfunctioning? After all, the officer did not directly witness the state of the light. The only person who saw the state of the light, was the person being charged with ignoring his/her light.

There's a reason these haven't caught on. Having a lit blue light as being the sole defense for a cop is ridiculous. At least red light cameras (A) are very obvious, (B) are signed for what they do, and (C) produce evidence that is especially difficult to argue against.

[jakeroot]

This has been my thinking as well.  Plus, in most cases, the opposing direction will turn red at the same time.  The cross street will have a light or green arrow that turns green a second or two later.  It would appear that there would be significantly more evidence that someone went thru a red light just by looking at the existing lights.

I remember when I first started seeing them around 2012, and just being baffled by them. I may not be an engineer, but I understand traffic flow well enough to tell you the state of a traffic light based on several pieces of information, 'rat lights' notwithstanding.

[Scott5114]

The rat lights are far better evidence against the driver than observing traffic patterns, because the cop can simply testify they knew the light was red because of the rat light. The driver would then have to prove that the rat light and the signal face were displaying different aspects, which is unlikely.

I guess I can see this point, but if circumstantial evidence is worthless, how could the cop actually prove the light was red? He didn't witness it anymore than any other drivers from whichever direction it was observed. The blue light is lit when that light is red, so far as we know, but couldn't a driver simply argue that his light was green and the light was malfunctioning? After all, the officer did not directly witness the state of the light. The only person who saw the state of the light, was the person being charged with ignoring his/her light.

So then the prosecutor calls an expert witness from the DOT that installed the light, and has them testify that the blue light is wired to light up when the signal head displays a red aspect. Therefore, since the cop said they saw the blue light, then the red light must be on. The defense could then argue that the blue light was malfunctioning, but to refute the expert testimony of the DOT witness you'd need something like a video of the rat light being on while the signal is green.

Note that none of this is particularly likely to actually transpire in court, since competently mounting a defense this complex would probably require a lawyer that charges more than it would cost to just pay the ticket, so it'd be pointless unless you're out to prove something.

[jeffandnicole]

The rat lights are far better evidence against the driver than observing traffic patterns, because the cop can simply testify they knew the light was red because of the rat light. The driver would then have to prove that the rat light and the signal face were displaying different aspects, which is unlikely.

I guess I can see this point, but if circumstantial evidence is worthless, how could the cop actually prove the light was red? He didn't witness it anymore than any other drivers from whichever direction it was observed. The blue light is lit when that light is red, so far as we know, but couldn't a driver simply argue that his light was green and the light was malfunctioning? After all, the officer did not directly witness the state of the light. The only person who saw the state of the light, was the person being charged with ignoring his/her light.

So then the prosecutor calls an expert witness from the DOT that installed the light, and has them testify that the blue light is wired to light up when the signal head displays a red aspect. Therefore, since the cop said they saw the blue light, then the red light must be on. The defense could then argue that the blue light was malfunctioning, but to refute the expert testimony of the DOT witness you'd need something like a video of the rat light being on while the signal is green.

Note that none of this is particularly likely to actually transpire in court, since competently mounting a defense this complex would probably require a lawyer that charges more than it would cost to just pay the ticket, so it'd be pointless unless you're out to prove something.

Not to mention that in most traffic court cases, the prosecutor isn't even aware how the dependent will fight against the ticket unless he's already submitted a request for discovery.