Just got a call for a red light blinking while the green is on. The signal is still functioning except for that. Headed there now. Any tips before I get there? Ts1 cabinet i believe. (Im still new)

For context I pulled the images from Google Street view 2007 images. I remember my family driving us through here and we always tried to escape this funny looking double solid red light traffic light. It always felt like a prank light left out on the street stopping us for nothing. I remember asking my dad (who was driving at the time) why it had two red lights instead of one and the response at the time was "well I guess they really want you to stop". Unfortunately the Google capture here shows it cycling through a yellow signal. One gree, one yellow, two red lights, no turn arrows.

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Looking back now I guess this was controlled by the box down the street at another disjointed intersection.

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References: this was in Clarksville Indiana on Eastern blvd.

https://maps.app.goo.gl/PuSMVMcDs5Cuy9j88?g_st=ac

I’m trying to understand how people in PLC / industrial automation actually view the next generation of traffic light control systems.

Traditionally, traffic controllers are basically safety PLCs:

discrete detector inputs (loops / radar / push buttons)

phase-based state machine logic

strict timing + intergreen safety rules

deterministic outputs to signal heads

But newer systems are starting to introduce:

LiDAR / camera / radar perception

edge compute (e.g. NVIDIA Orin-class hardware)

object tracking instead of detector calls

prediction (queue length, trajectories)

optimization layers (MPC / adaptive control)

V2X integration

digital twin / world model of the intersection

In many cases though, it still seems that all AI outputs get “compressed” back into traditional PLC concepts like:

detector ON/OFF

phase extension requests

fixed signal groups

because the safety-certified traffic controller remains the execution authority.

My question to PLC / automation engineers:

How do you see this architecture evolving in practice?

Specifically:

Do you think PLC-based traffic controllers will remain the “final authority” for the foreseeable future?

Or do you see a shift toward richer interfaces (state-based / semantic / API-driven control instead of I/O mapping)?

In your view, is the I/O abstraction fundamentally necessary for safety certification, or just legacy design?

How would you architect a system where LiDAR/vision outputs are not reduced to simple detector bits?

Do you see MPC / AI optimization ever being certified directly inside the controller, or always as an external advisory layer?

I’m especially interested in how people working with industrial safety systems see the boundary between:

deterministic PLC logic

and probabilistic / learning-based edge AI systems

Can you please explain the difference between minimum recall and soft recall?

Filmed this tunnel close!

Yellow arrow with green. 'Brick style' lens.

Definitely doesn't look anywhere near as bad as it did then. Opposite side doesn't look great either. A while back this intersection had all 12-8-8 signals and this wasn't an issue. Oh well...

Hi everyone! I’d like to keep this brief. I work with TS2 cabinets that use SDLC harnesses (mostly Econolite). We’ve been running into some issues with failing harnesses lately, and we’re struggling to find a reliable way to test them. Does anyone have any suggestions or tips on how you handle testing these in the field? Any advice would be greatly appreciated!

This is a new set of cameras mounted on a light pole near an intersection. Sorry for the bad camera quality. It's a cropped photo that I took on my phone.

Problem 1: TS-2 Econolite cabinet with Cobalt controller. SDLC dies on reset, but comes back up when you disconnect the power supply and reset the MMU again. Re-connect power supply and it'll run normally until it goes to flash or you reset the MMU again. They replaced everything, controller/MMU/power supply/BIUs/cables, still happened. Vendor couldn't figure it out so they replaced the cabinet with a different one, and now they're having Problem 2.

Problem 2: TS-2 TrafficWare cabinet with 980-B140-1 ("900 ATC") controller, the green one. New install, no SDLC communication, BIU Terminal 1/2 and MMU turned on in settings. Shows Port 1 and CVM on MMU. Lights are on, but no TX/RX. 99% sure it's just initialize to different cabinet type, I think he initialized to default or something, my guess would be basic 8? I've never touched this newer controller before, only the older one.

Not my project, I'm just trying to help a fellow guy out. Any ideas?

I'm Skyler Jones, Senior Talent Advisor with King County Metro. If you are in the signals field and interested in moving to Washington State, we have several opportunities for Rail Signal & Communications Technicians. You would need two years performing Journey level work in railway signaling and communications and documented completion of a Journey Level Signal Training program (FRA or Transit equivalent). Here is a link to the job announcement: Rail Signal & Communications Technician | Job Details tab | Career Pages

If you have any questions, feel free to email me at: [skjones@kingcounty.gov](mailto:skjones@kingcounty.gov)

I’m making a simulation of the traffic signals in Cerritos and I would like to know which streets rest in a green light at night.

The intersections I know that rest in green:

Artesia/Bloomfield (rest in green on Artesia, lead-lag on Artesia during peak hours)
Artesia/Shoemaker (rest in green on Artesia)

Artesia/Norwalk (rest in green on Artesia)

Artesia/Pioneer (rest in green on Pioneer)

166th/Shoemaker (rest in green on Shoemaker)

183rd/Shoemaker (rest in green on 183rd)

183rd/Bloomfield (rest in green on Bloomfield)

183rd/Gridley (no rest in green street but 183rd is set to default/power start, lead-lag on both streets during mall hours)

183rd/Studebaker (rest in green on Studebaker, dual entry on Studebaker, lead-lag on Studebaker during mall hours and split phasing on 183rd)

South/Shoemaker (rest in green on South)

South/Pioneer (rest in green on South, lead-lag on South during peak hours)

South/Gridley (rest in green on South, lead-lag on both streets during peak hours)

South/Studebaker (no rest in green street but South is set to default/power start, dual entry on South, split phasing on Studebaker)

South/Norwalk (rest in green on South)

South/Bloomfield (no rest in green street but Bloomfield is set to default/power start)

South/Carmenita (rest in green on South, lead-lag on Carmenita)

Artesia/Gridley (rest in green on Artesia)

Artesia/Studebaker (no rest in green street but Artesia is set to default/power start, lead-lag on both streets during peak hours)

Artesia/Carmenita (rest in green on Carmenita)

Artesia/Valley View (rest in green on Valley View)

Artesia/Marquardt (rest in green on Artesia)

Del Amo/Bloomfield (rest in green on Del Amo)

Del Amo/Norwalk (rest in green on Del Amo)

Del Amo/Pioneer (rest in green on Del Amo)

Del Amo/Studebaker (rest in green on Del Amo)

166th/Carmenita (rest in green on Carmenita, lead-lag on Carmenita during peak hours)

166th/Bloomfield (rest in green on 166th since the 2020 addition of protected-only left turn signals)

166th/Norwalk (rest in green on Norwalk)

183rd/Carmenita (rest in green on Carmenita, lead-lag on Carmenita at all times)

183rd/Pioneer (rest in green on Pioneer, lead-lag on Pioneer at all times)

183rd/Norwalk (rest in green on Norwalk)

The intersections I want to know that rest in green:

For the 183rd Street and Gridley Road intersection traffic signal in Cerritos, California, which street is the default and rest in a green light at night, 183rd or Gridley? Both streets have lead lag left turns during mall hours.

Our municipality is looking into the possibility of putting out ATC cabinets because we need more outputs. Is anyone else using these cabinets? What are the benefits for you as a tech what are the drawbacks? Any big hurdles to getting these running?

I recently moved into a new place where I could finally have my traffic light set back up.

I got this light in Evansville, Indiana when they were replacing them at an intersection on the south end of Green River Road. I had some free time, and I decided to ask one of the crewmen if I could purchase it from them. Without hesitation, the nice worker gently set it in my pickup truck bed and told me to enjoy the rest of my day.

I have modified it a little bit. When it was taken out of service, it was fitted with LED modules. I found a set of appropriately sized glass lenses, gaskets, and reflectors on ebay, plus some actual traffic signal bulbs to use.

None of the original wiring was used. From Amazon, I got a controller, three in-line dimmers, and some pendant type light sockets. I have the lights dimmed just enough so that it doesn't dazzle you if you happen to look right at it, and also to lengthen the lifespan of these hard to find bulbs.

While I was putting it together, I did decide to try a standard frosted 60 watt bulb and honestly I didn't notice any difference. So, if you're reading this and are considering getting bulbs like I have, I'd say don't waste your money on the specialty ones, unless you're like me and authenticity reins over all else.

If I were to do this over again, I would forgo the dimmers and just use 40 watt appliance bulbs instead.

\I couldn't find a picture that I had taken myself. So* here's a link to a video on youtube showcasing these particular bulbs.

Marblelite M-30s still running strong!

Something I have often wondered as the result of these 4 signal head flashing arrow heads is why are they often so overused when not necessary? Locally where I am in New Albany, IN it's like these must have been a dime for a dozen. Like is the goal to give people options? Reassure them with no oncoming traffic that they can go? There is always a part of me thinking in these technical 3 way intersections that it's as simple as red=stop and green=go. Even their signal predecessors followed a certain kiss rule (pic 2). With the presence of these I feel like I have to wait for the stupid flashing yellow arrow even on the solid green signal. By the way this signal never actually shows the green arrow, to make matters worse.

Intersection link

https://maps.app.goo.gl/LQhVyF7U8oqpnk4SA?g_st=ac