19 ms·

What's in those mysterious cabinets?

148 points by jamesbowman 8y ago

peterwwillis 8y ago
Further reading: How Traffic Light Control Systems Work (https://www.autoevolution.com/news/how-do-traffic-light-control-systems-work-41839.html https://www.autoevolution.com/news/how-do-traffic-light-cont...) Traffic Signal Operations and Maintenance Staffing Guidelines (https://ops.fhwa.dot.gov/publications/fhwahop09006/fhwahop09006.pdf https://ops.fhwa.dot.gov/publications/fhwahop09006/fhwahop09...) TRAFFIC SIGNAL OPERATIONS HANDBOOK (https://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/0-5629-P1.pdf https://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents...) TRAFFIC SIGNAL DESIGN – OPERATIONS AND COORDINATION (https://www.tn.gov/content/dam/tn/tdot/documents/TDOT_Traffic_Design_Manual_Chapter_07_Dec2016.pdf https://www.tn.gov/content/dam/tn/tdot/documents/TDOT_Traffi...) Design of an ITS-Level Advanced Traffic Management System: A Human Factors Perspective (1996) https://www.fhwa.dot.gov/publications/research/safety/95181/95181.pdf https://www.fhwa.dot.gov/publications/research/safety/95181/...
Taniwha 8y ago
when I was a kid (a long time ago) those cabinets were full of electro-mechanical relays, you could hear them clicking. I discovered that by thumping against the box hard the traffic lights would suddenly change so I could cross. I did this exactly once because while no one had an accident the traffic got a bit hairy for a minute as lights changed early without a yellow phase ....
- tallanvor 8y ago
  I'm not sure just how accurate it was, but I still remember the first season MacGyver episode "Thief of Budapest" where he adjusted the settings to create a traffic jam.
  - jfk13 8y ago
    That sounds a lot like https://en.wikipedia.org/wiki/The_Italian_Job#Plot https://en.wikipedia.org/wiki/The_Italian_Job#Plot
- Analemma_ 8y ago
  I'm willing to bet you forced the system into an all-red "safe mode" when it detected tampering.
surgeryres 8y ago
This post is one of the many reasons I love HN. In depth discussion of obscure (but very interesting) topics; and the personal websites that host them.
lallysingh 8y ago
This is the first time I've seen an HC11 used outside of educational contexts.
- tonyarkles 8y ago
  You’d be amazed at how prevalent they are. I come across them at least a couple times a year when popping the lid off this thing or that. Generally older gear :). The most recent that comes to mind is a radio repeater.
  - HeyLaughingBoy 8y ago
    At one point (maybe about 20 years ago), 'HC11, 'HC05 and 8051 variants made up the bulk of all microcontrollers in use. I wonder what's replaced them. My vote is for Atmel Tiny/Mega, but I'm biased...
EvanAnderson 8y ago
Yikes, those are some dirty fiber terminations! I wonder what's in there that needs single-mode fiber.
- Treblemaker 8y ago
  Could it be connections to other nearby signals for synchronizing the lights?
  - greenyoda 8y ago
    Also possibly a connection to a central traffic control center that can override signals during emergencies or special events that generate abnormal traffic flows.
    - JdeBP 8y ago
      I mentioned SCOOT elsewhere in this discussion. With such systems, overriding is (I was told) the norm. The isolated controller on fixed timing is the fallback case.
- stephen_g 8y ago
  I'm not sure about the US, but in Australia pretty much all traffic signals in metro areas are all linked and controlled over fibre networks. You need single mode fibre given the distances between cabinets etc. (hundreds of metres to kilometres). And if you're doing that, may as well just use single mode internally too because the transceivers and patch cables aren't really much different in price and you can get better volume discounts.
- walrus01 8y ago
  Without seeing the ferrule to ferrule contact it's hard to say if the termination is really dirty. Yes the jacket is dirty. What they have done that is a cardinal sin is running the fiber between equipment through the center of a rack rather than around or above. I hope whoever installed that has a good cletop, fiber scope, set of ferrule sleeve cleaning swabs, push click cleaning tool. Also hard to say if it's dirty or bad without seeing the back/internal side of that patch panel. Knowing city governments it could be anything from a dreadful mechanical splice to a perfectly done core alignment fusion splicer with 0.01 loss.
spchampion2 8y ago
I've always wondered why those cabinets are so big. Traffic light controls seem like the kind of thing that could be reduced to a much smaller package given greater computing power combined with smaller and more efficient hardware. What does all the hardware inside actually do?
- ams6110 8y ago
  probably sized to house standard rack-mount gear.
- greenyoda 8y ago
  Maybe one box needs to communicate with a network of other boxes to keep traffic in sync over a wider area. I'm guessing that the bottom rack with the yellow cables plugged into it is some kind of networking gear. Also, the equipment has to switch some fairly high-power loads - until the recent adoption of LED-based traffic lights, I'd guess that traffic light bulbs probably drew a few hundred watts each, and there can be many lights in a large intersection. You can see a row of 15A and 20A circuit breakers in the box in the photo, on the left side of the second rack from the top, with a 50A main breaker below them. The equipment below that rack looks like power-switching modules. It's also entirely possible that this equipment is 20 or 30 years old, built at a time when computer hardware was much bulkier. There would be little incentive to replace it with something smaller if it was still working reliably.
  - AstralStorm 8y ago
    In fact, this being repairable in the field by a person with a soldering iron and a bag of parts is a consideration. Sometimes you cannot just get a full module to swap.
    - _jal 8y ago
      This. Repairability and durability are two reasons a lot of 'old tech' is in use. I have a friend who is an engineer with PG&E who is great to take to parties full of tech nerds. They're always horrified by the '100 year old tech' running the grid. My take is that they're right to be horrified by the fragility of the grid, but have the 'why' exactly backwards - it isn't the vats of oil that make it fragile.
walrus01 8y ago
In case anyone is wondering very similar cabinets are also used for telecom in major cities. Shaw has sidewalk mounted cabinets throughout Vancouver for part of their fiber and cable TV network, and there's Telus pedestal/junction cabinets as well. https://www.google.com/search?q=telecom+cabinet+outdoor&num=100&client=ubuntu&hs=mKR&channel=fs&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjyxMzDlebaAhWHsVQKHW5UCqsQ_AUICigB&biw=1493&bih=2011 https://www.google.com/search?q=telecom+cabinet+outdoor&num=... I have seen models very similar to traffic control system cabinets used for patch panels for fiber + 1RU sized routers and switches, medium sized UPS, etc.
- TheCapn 8y ago
  Once you're used to looking at electrical enclosures they all sort of start to look the same. What you're describing in your photos are similar to what my company designs for all forms of industrial domains: agriculture, wastewater, oil & gas, mining, telecom, power, etc. https://www.hammfg.com/electrical https://www.hammfg.com/electrical Elsewhere in this thread someone talks about "optimization" and electrical enclosures are no different. There's various levels of certification that they need to meet in regards to the different environments they're installed to work in, it only makes sense that a standard style of design emerges instead of specifically engineering something per task. (EDIT: I should mention I do not work for hammond, I just linked their site because I know we use their enclosures a lot)
  - HeyLaughingBoy 8y ago
    Guessing you work for a panel builder?
    - TheCapn 8y ago
      We have a shop that builds panels. I'm up in engineering working with guys who design them.
deathanatos 8y ago
> What is ramp metering? (The Bay Area contingent of HN can answer that!) Traffic lights (typically red/green only) at the bottom of on-ramps that rate-limit ("meter") traffic onto the freeway, typically during rush hour. You drive up to a red, stop, it turns green and you go. (Sometimes a sign indicates that 2 cars get to go per green given.) There are usually sensors embedded in the rightmost lane of the freeway shortly before the merge point, and on a good day, it feels like it gives you a green timed with a gap. (Although I think it also sometimes just times out and lets you go, in which case, no gap.) The ones here have an HOV lane and a non-HOV lane, usually; typically they just force the HOV lane to come to a near stop before turning green; I think that's more to slow the HOV traffic down to avoid collisions with the adjoining non-HOV lane should their light also turn green, but it feels like a weird formality when driving it. Some days the cops sit on the ramp pulling people cheating in the HOV lane. https://en.wikipedia.org/wiki/Ramp_meter https://en.wikipedia.org/wiki/Ramp_meter It is one of the two things I warn family visiting that have never visited before. (In the majority of the US, you just get on the highway, there isn't a traffic light at the bottom of a ramp, that'd be absurd, since you're wanting to accelerate to ~70mph.) (The other is lane splitting: motorcycles will (ab)use the dividing line, particularly between lanes 1 & 2, to pass.)
- flomo 8y ago
  On a similar note: > Did you know that the long pointy triangle thing is called a “gore”? > Well, you might survive, because there is a thing there that is designed to crush when you hit it. It might be a QuadGuard Elite Crash Cushion System Or it might be the traditional solution, which is a bunch of rubbermaid garbage pails filled with water. (Not that long ago, I was trying to let someone merge in front of me, but they couldn't make up their minds and ended up slamming their brakes into the gore. I bet they had fun getting out of there.)
  - notatoad 8y ago
    >Or it might be the traditional solution, which is a bunch of rubbermaid garbage pails filled with water. only if you live in a place where water doesn't freeze
jaaames 8y ago
I only found out about these a few months ago because there was always a cop leaning against one outside a ballpark before and after games with a radio plugged into it. I asked what he was doing and he gladly showed me that he was just manually cycling the lights, basically on a longer delay where required to clear jams and work with another cop directing traffic.
_bxg1 8y ago
Reminds me of this scene from MI3 https://m.youtube.com/watch?v=ojRRr3nOD3Y https://m.youtube.com/watch?v=ojRRr3nOD3Y The joke was supposed to be that his cover job sounds boring, but I always thought it sounded fascinating
- droidist2 8y ago
  It reminds me of that scene in Hackers, which was based on this scene from the original Italian Job https://youtube.com/watch?v=5FzBMjJ803I https://youtube.com/watch?v=5FzBMjJ803I
guessmyname 8y ago
> It's such a big world out there, so much to know. I love this type of articles, there really is so much out there to learn. I always found myself thinking, while waiting for the green light: * Who makes these traffic lights? * What software controls the traffic system? * Are all traffic systems controlled by the same organizations? * Can they get hacked? Of course they can… Are they difficult to hack? * How can someone land a job to work on this type of SCADA systems? I am right now sending my resume to McCain [1] they are currently looking for .Net, Java and Embedded engineers. If I don't get any of these jobs, at least I know where to continue looking. My dream have always been to work in projects like that, someone people consider them boring, I find them very interesting. Wish me luck :-) [1] https://www.mccain-inc.com/company/careers https://www.mccain-inc.com/company/careers
- JdeBP 8y ago
  > What software controls the traffic system? One such software is SCOOT, which has been around since 1979. The name is an initialism for Split Cycle Offset Optimization Technique. All of these are traffic light jargon: the red/green split, the cycle length, and the green phase offset. * https://trlsoftware.co.uk/products/traffic_control/scoot https://trlsoftware.co.uk/products/traffic_control/scoot > Are they difficult to hack? Yes, in part because it involves forgetting all of the dramatized baloney that you've seen on television. It's not done from a wireless laptop in the back of a moving car magically giving the protagonists a green wave at the opportune time with zero notice and preparation. For starters, in some places around the world much of this infrastructure was interconnected long before WiFi was even invented. There will be telecommunications lines to a central control office, and it is there that one would attack the system. Think of the original Italian Job movie, where a replacement tape at the control centre subverted the system. One would also attack it at these various roadside cabinets. (This is not to say that no systems use radio. Several do, and their vulnerabilities are appalling. But this is not universal. And the vulnerabilities lie in things like operating systems that were invented long after computer-managed traffic light systems for cities themselves were, meaning that said operating systems are not universal either.) * https://www.usenix.org/conference/woot14/workshop-program/presentation/ghena https://www.usenix.org/conference/woot14/workshop-program/pr...
- 8y ago
mutagen 8y ago
Want to rabbit-hole deep on traffic engineering? There’s a long-running thread on the Something Awful forums about traffic engineering: https://forums.somethingawful.com/showthread.php?threadid=3177805 https://forums.somethingawful.com/showthread.php?threadid=31... Traffic controls, intersection design, role playing regional transportation planning, and much much more.
unwind 8y ago
I think I understand what variable message signs are, and I can guess at changeable lane control, but what are the sprinklers and pumps for? What is ramp metering? Very interesting (as always with good geekery almost regardless of actual subject matter), but so frustrating that the part about pumps and sprinklers not being answered. The linked-to PDF in the article (the one that the quote above comes from) doesn't mention sprinklers or pumps more than once, either. I guess traffic intersections often have decorative planting which might need watering and it would make sense to make the already-present light controller handle that, too. That's my best guess, at least. Some basic googling didn't turn up anything useful.
- owlninja 8y ago
  There has been a followup if you go to the homepage "DOTs in California and presumably elsewhere often have a need for erosion control on the steep inclines of earth surrounding their highway ramps. So any time you see a 45-degree incline covered in greenery, chances are it has a sprinkler system attached and carefully maintained by the DOT. Those same sprinklers are often within a few feet of the ramp's metering lights…"
kqr 8y ago
Re. technical domains you may not know exist: airplane flatware logistics. When you want to look at something optimised, start with things that are expensive to run. Airports are expensive in nearly every sense of the word, so it's a place where you find things being optimised to hell and back. Outgoing passenger flights may need clean, fresh flatware. The window in time allocated to unload dirty flatwar and load a clean batch is small; that cart of flatware needs to be in exactly the right place at the right time, or there will be delays, which will cost a lot of money to someone. So, naturally, the strategies on how to get flatware onto airplanes is an area of deep study. I talked to a friend of a friend at a party about this, since it was their subject of study. They thought they were studying the most boring thing in the world and I couldn't make them understand why it fascinated me.
- wingerlang 8y ago
  What were some of the strategies?
  - kqr 8y ago
    Unfortunately, I don't remember too many specifics, but a web search for "ground handling operations technical perspective" seems to bring up an overview with pretty graphs which might serve as a decent starting point for further research.
- mseebach 8y ago
  Is flatware logistics really a separate field? I get that the general logistics of handling "cabin consumables" is a big deal, but it seems to me that most flatware is integrated in the food carts? Semi-relevant anecdote: I once rebooked last minute on to a flight and as I was boarding perhaps 15 minutes later as one of the last passengers, a guy in a high-viz vest came half-running down the jetway and handed the cabin crew a box with one single premium economy meal. I was rather impressed by the operation, and a bit apprehensive about declining the meal once in the air.
- sjcsjc 8y ago
  Native Brit here. Never come across the word flatware before. It appears to be a US term. Or maybe I'm just ignorant. 1. utensils, as knives, forks, and spoons, used at the table for serving and eating food. 2. dishes or containers for the table that are more or less flat, as plates and saucers (source: the internet)
speps 8y ago
Follow-up post [1] with explanation of "ramp metering" and "sprinklers". [1] https://blog.plover.com/addenda/201804.html https://blog.plover.com/addenda/201804.html
draw_down 8y ago
Well, some mysteries are bigger than others.
mojomark 8y ago
At 5AM, as I sit waiting for a traffic light on a deserted stretch of road during my morning commute, glaring tempestuously at the nearby redlight camera, I wonder how we've gotten to driverless cars before getting to 'smart' intersection signaling systems that know there is a lone commuter patiently waiting to pass.
- steindavidb 8y ago
  It has to do a lot with reliability and cost. A smart car has a lot of expensive sensors and an expected life of a few years with regular maintenance. There's also a huge market opportunity around smart cars. Those cabinets can last decades, in all conditions, with minimal upkeep. Adding sensors decreases reliability and increases maintenance cost. There isn't usually an appetite to put traffic signal upgrades or extra maintenance headcount in city budgets for non-critical infrastructure upgrades, so the financial incentives to innovate are more limited as well.
  - mojomark 8y ago
    Thanks - interesting. I know traffic pattern/flow models and studies can be extremely complex. However, from the perspective of a 'dumb' commuter, it seems like the investment in smarter traffic signals would be offset by global savings from/economic benefits of reduced congestion (e.g. idle bus transit fuel/maintenance savings or generally increased standard of living and economic imprivements due to increased traffic flow).
    - kqr 8y ago
      It is useful to talk about both inefficiency (the thing you point out) and exploitability (the ability for any individual actor to make useful amounts of money out of fixing the inefficiency.) Unless an area is both inefficient and exploitable, it is plausible that it will go unfixed for a long time. When you start viewing it in those terms, you find obvious inefficiencies everywhere.
- dmckeon 8y ago
  I wonder if the transition from human-driven vehicles to self-driving will bring a resurgence of traffic circles in the US as an intersection that can readily support any mixture of self-driven and human-driven.

148 points by jamesbowman 8y ago

Further reading: How Traffic Light Control Systems Work (https://www.autoevolution.com/news/how-do-traffic-light-control-systems-work-41839.html https://www.autoevolution.com/news/how-do-traffic-light-cont...) Traffic Signal Operations and Maintenance Staffing Guidelines (https://ops.fhwa.dot.gov/publications/fhwahop09006/fhwahop09006.pdf https://ops.fhwa.dot.gov/publications/fhwahop09006/fhwahop09...) TRAFFIC SIGNAL OPERATIONS HANDBOOK (https://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/0-5629-P1.pdf https://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents...) TRAFFIC SIGNAL DESIGN – OPERATIONS AND COORDINATION (https://www.tn.gov/content/dam/tn/tdot/documents/TDOT_Traffic_Design_Manual_Chapter_07_Dec2016.pdf https://www.tn.gov/content/dam/tn/tdot/documents/TDOT_Traffi...) Design of an ITS-Level Advanced Traffic Management System: A Human Factors Perspective (1996) https://www.fhwa.dot.gov/publications/research/safety/95181/95181.pdf https://www.fhwa.dot.gov/publications/research/safety/95181/...

Taniwha 8y ago

when I was a kid (a long time ago) those cabinets were full of electro-mechanical relays, you could hear them clicking. I discovered that by thumping against the box hard the traffic lights would suddenly change so I could cross. I did this exactly once because while no one had an accident the traffic got a bit hairy for a minute as lights changed early without a yellow phase ....

tallanvor 8y ago
I'm not sure just how accurate it was, but I still remember the first season MacGyver episode "Thief of Budapest" where he adjusted the settings to create a traffic jam.
- jfk13 8y ago
  That sounds a lot like https://en.wikipedia.org/wiki/The_Italian_Job#Plot https://en.wikipedia.org/wiki/The_Italian_Job#Plot
Analemma_ 8y ago
I'm willing to bet you forced the system into an all-red "safe mode" when it detected tampering.

surgeryres 8y ago

This post is one of the many reasons I love HN. In depth discussion of obscure (but very interesting) topics; and the personal websites that host them.

lallysingh 8y ago

This is the first time I've seen an HC11 used outside of educational contexts.

tonyarkles 8y ago
You’d be amazed at how prevalent they are. I come across them at least a couple times a year when popping the lid off this thing or that. Generally older gear :). The most recent that comes to mind is a radio repeater.
- HeyLaughingBoy 8y ago
  At one point (maybe about 20 years ago), 'HC11, 'HC05 and 8051 variants made up the bulk of all microcontrollers in use. I wonder what's replaced them. My vote is for Atmel Tiny/Mega, but I'm biased...

EvanAnderson 8y ago

Yikes, those are some dirty fiber terminations! I wonder what's in there that needs single-mode fiber.

Treblemaker 8y ago
Could it be connections to other nearby signals for synchronizing the lights?
- greenyoda 8y ago
  Also possibly a connection to a central traffic control center that can override signals during emergencies or special events that generate abnormal traffic flows.
  - JdeBP 8y ago
    I mentioned SCOOT elsewhere in this discussion. With such systems, overriding is (I was told) the norm. The isolated controller on fixed timing is the fallback case.
stephen_g 8y ago
I'm not sure about the US, but in Australia pretty much all traffic signals in metro areas are all linked and controlled over fibre networks. You need single mode fibre given the distances between cabinets etc. (hundreds of metres to kilometres). And if you're doing that, may as well just use single mode internally too because the transceivers and patch cables aren't really much different in price and you can get better volume discounts.
walrus01 8y ago
Without seeing the ferrule to ferrule contact it's hard to say if the termination is really dirty. Yes the jacket is dirty. What they have done that is a cardinal sin is running the fiber between equipment through the center of a rack rather than around or above. I hope whoever installed that has a good cletop, fiber scope, set of ferrule sleeve cleaning swabs, push click cleaning tool. Also hard to say if it's dirty or bad without seeing the back/internal side of that patch panel. Knowing city governments it could be anything from a dreadful mechanical splice to a perfectly done core alignment fusion splicer with 0.01 loss.

spchampion2 8y ago

I've always wondered why those cabinets are so big. Traffic light controls seem like the kind of thing that could be reduced to a much smaller package given greater computing power combined with smaller and more efficient hardware. What does all the hardware inside actually do?

ams6110 8y ago
probably sized to house standard rack-mount gear.
greenyoda 8y ago
Maybe one box needs to communicate with a network of other boxes to keep traffic in sync over a wider area. I'm guessing that the bottom rack with the yellow cables plugged into it is some kind of networking gear. Also, the equipment has to switch some fairly high-power loads - until the recent adoption of LED-based traffic lights, I'd guess that traffic light bulbs probably drew a few hundred watts each, and there can be many lights in a large intersection. You can see a row of 15A and 20A circuit breakers in the box in the photo, on the left side of the second rack from the top, with a 50A main breaker below them. The equipment below that rack looks like power-switching modules. It's also entirely possible that this equipment is 20 or 30 years old, built at a time when computer hardware was much bulkier. There would be little incentive to replace it with something smaller if it was still working reliably.
- AstralStorm 8y ago
  In fact, this being repairable in the field by a person with a soldering iron and a bag of parts is a consideration. Sometimes you cannot just get a full module to swap.
  - _jal 8y ago
    This. Repairability and durability are two reasons a lot of 'old tech' is in use. I have a friend who is an engineer with PG&E who is great to take to parties full of tech nerds. They're always horrified by the '100 year old tech' running the grid. My take is that they're right to be horrified by the fragility of the grid, but have the 'why' exactly backwards - it isn't the vats of oil that make it fragile.

walrus01 8y ago

In case anyone is wondering very similar cabinets are also used for telecom in major cities. Shaw has sidewalk mounted cabinets throughout Vancouver for part of their fiber and cable TV network, and there's Telus pedestal/junction cabinets as well. https://www.google.com/search?q=telecom+cabinet+outdoor&num=100&client=ubuntu&hs=mKR&channel=fs&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjyxMzDlebaAhWHsVQKHW5UCqsQ_AUICigB&biw=1493&bih=2011 https://www.google.com/search?q=telecom+cabinet+outdoor&num=... I have seen models very similar to traffic control system cabinets used for patch panels for fiber + 1RU sized routers and switches, medium sized UPS, etc.

TheCapn 8y ago
Once you're used to looking at electrical enclosures they all sort of start to look the same. What you're describing in your photos are similar to what my company designs for all forms of industrial domains: agriculture, wastewater, oil & gas, mining, telecom, power, etc. https://www.hammfg.com/electrical https://www.hammfg.com/electrical Elsewhere in this thread someone talks about "optimization" and electrical enclosures are no different. There's various levels of certification that they need to meet in regards to the different environments they're installed to work in, it only makes sense that a standard style of design emerges instead of specifically engineering something per task. (EDIT: I should mention I do not work for hammond, I just linked their site because I know we use their enclosures a lot)
- HeyLaughingBoy 8y ago
  Guessing you work for a panel builder?
  - TheCapn 8y ago
    We have a shop that builds panels. I'm up in engineering working with guys who design them.

deathanatos 8y ago

> What is ramp metering? (The Bay Area contingent of HN can answer that!) Traffic lights (typically red/green only) at the bottom of on-ramps that rate-limit ("meter") traffic onto the freeway, typically during rush hour. You drive up to a red, stop, it turns green and you go. (Sometimes a sign indicates that 2 cars get to go per green given.) There are usually sensors embedded in the rightmost lane of the freeway shortly before the merge point, and on a good day, it feels like it gives you a green timed with a gap. (Although I think it also sometimes just times out and lets you go, in which case, no gap.) The ones here have an HOV lane and a non-HOV lane, usually; typically they just force the HOV lane to come to a near stop before turning green; I think that's more to slow the HOV traffic down to avoid collisions with the adjoining non-HOV lane should their light also turn green, but it feels like a weird formality when driving it. Some days the cops sit on the ramp pulling people cheating in the HOV lane. https://en.wikipedia.org/wiki/Ramp_meter https://en.wikipedia.org/wiki/Ramp_meter It is one of the two things I warn family visiting that have never visited before. (In the majority of the US, you just get on the highway, there isn't a traffic light at the bottom of a ramp, that'd be absurd, since you're wanting to accelerate to ~70mph.) (The other is lane splitting: motorcycles will (ab)use the dividing line, particularly between lanes 1 & 2, to pass.)

flomo 8y ago
On a similar note: > Did you know that the long pointy triangle thing is called a “gore”? > Well, you might survive, because there is a thing there that is designed to crush when you hit it. It might be a QuadGuard Elite Crash Cushion System Or it might be the traditional solution, which is a bunch of rubbermaid garbage pails filled with water. (Not that long ago, I was trying to let someone merge in front of me, but they couldn't make up their minds and ended up slamming their brakes into the gore. I bet they had fun getting out of there.)
- notatoad 8y ago
  >Or it might be the traditional solution, which is a bunch of rubbermaid garbage pails filled with water. only if you live in a place where water doesn't freeze

jaaames 8y ago

I only found out about these a few months ago because there was always a cop leaning against one outside a ballpark before and after games with a radio plugged into it. I asked what he was doing and he gladly showed me that he was just manually cycling the lights, basically on a longer delay where required to clear jams and work with another cop directing traffic.

_bxg1 8y ago

Reminds me of this scene from MI3 https://m.youtube.com/watch?v=ojRRr3nOD3Y https://m.youtube.com/watch?v=ojRRr3nOD3Y The joke was supposed to be that his cover job sounds boring, but I always thought it sounded fascinating

droidist2 8y ago
It reminds me of that scene in Hackers, which was based on this scene from the original Italian Job https://youtube.com/watch?v=5FzBMjJ803I https://youtube.com/watch?v=5FzBMjJ803I

guessmyname 8y ago

> It's such a big world out there, so much to know. I love this type of articles, there really is so much out there to learn. I always found myself thinking, while waiting for the green light: * Who makes these traffic lights? * What software controls the traffic system? * Are all traffic systems controlled by the same organizations? * Can they get hacked? Of course they can… Are they difficult to hack? * How can someone land a job to work on this type of SCADA systems? I am right now sending my resume to McCain [1] they are currently looking for .Net, Java and Embedded engineers. If I don't get any of these jobs, at least I know where to continue looking. My dream have always been to work in projects like that, someone people consider them boring, I find them very interesting. Wish me luck :-) [1] https://www.mccain-inc.com/company/careers https://www.mccain-inc.com/company/careers

JdeBP 8y ago
> What software controls the traffic system? One such software is SCOOT, which has been around since 1979. The name is an initialism for Split Cycle Offset Optimization Technique. All of these are traffic light jargon: the red/green split, the cycle length, and the green phase offset. * https://trlsoftware.co.uk/products/traffic_control/scoot https://trlsoftware.co.uk/products/traffic_control/scoot > Are they difficult to hack? Yes, in part because it involves forgetting all of the dramatized baloney that you've seen on television. It's not done from a wireless laptop in the back of a moving car magically giving the protagonists a green wave at the opportune time with zero notice and preparation. For starters, in some places around the world much of this infrastructure was interconnected long before WiFi was even invented. There will be telecommunications lines to a central control office, and it is there that one would attack the system. Think of the original Italian Job movie, where a replacement tape at the control centre subverted the system. One would also attack it at these various roadside cabinets. (This is not to say that no systems use radio. Several do, and their vulnerabilities are appalling. But this is not universal. And the vulnerabilities lie in things like operating systems that were invented long after computer-managed traffic light systems for cities themselves were, meaning that said operating systems are not universal either.) * https://www.usenix.org/conference/woot14/workshop-program/presentation/ghena https://www.usenix.org/conference/woot14/workshop-program/pr...
8y ago

mutagen 8y ago

Want to rabbit-hole deep on traffic engineering? There’s a long-running thread on the Something Awful forums about traffic engineering: https://forums.somethingawful.com/showthread.php?threadid=3177805 https://forums.somethingawful.com/showthread.php?threadid=31... Traffic controls, intersection design, role playing regional transportation planning, and much much more.

unwind 8y ago

I think I understand what variable message signs are, and I can guess at changeable lane control, but what are the sprinklers and pumps for? What is ramp metering? Very interesting (as always with good geekery almost regardless of actual subject matter), but so frustrating that the part about pumps and sprinklers not being answered. The linked-to PDF in the article (the one that the quote above comes from) doesn't mention sprinklers or pumps more than once, either. I guess traffic intersections often have decorative planting which might need watering and it would make sense to make the already-present light controller handle that, too. That's my best guess, at least. Some basic googling didn't turn up anything useful.

owlninja 8y ago
There has been a followup if you go to the homepage "DOTs in California and presumably elsewhere often have a need for erosion control on the steep inclines of earth surrounding their highway ramps. So any time you see a 45-degree incline covered in greenery, chances are it has a sprinkler system attached and carefully maintained by the DOT. Those same sprinklers are often within a few feet of the ramp's metering lights…"

kqr 8y ago

Re. technical domains you may not know exist: airplane flatware logistics. When you want to look at something optimised, start with things that are expensive to run. Airports are expensive in nearly every sense of the word, so it's a place where you find things being optimised to hell and back. Outgoing passenger flights may need clean, fresh flatware. The window in time allocated to unload dirty flatwar and load a clean batch is small; that cart of flatware needs to be in exactly the right place at the right time, or there will be delays, which will cost a lot of money to someone. So, naturally, the strategies on how to get flatware onto airplanes is an area of deep study. I talked to a friend of a friend at a party about this, since it was their subject of study. They thought they were studying the most boring thing in the world and I couldn't make them understand why it fascinated me.

wingerlang 8y ago
What were some of the strategies?
- kqr 8y ago
  Unfortunately, I don't remember too many specifics, but a web search for "ground handling operations technical perspective" seems to bring up an overview with pretty graphs which might serve as a decent starting point for further research.
mseebach 8y ago
Is flatware logistics really a separate field? I get that the general logistics of handling "cabin consumables" is a big deal, but it seems to me that most flatware is integrated in the food carts? Semi-relevant anecdote: I once rebooked last minute on to a flight and as I was boarding perhaps 15 minutes later as one of the last passengers, a guy in a high-viz vest came half-running down the jetway and handed the cabin crew a box with one single premium economy meal. I was rather impressed by the operation, and a bit apprehensive about declining the meal once in the air.
sjcsjc 8y ago
Native Brit here. Never come across the word flatware before. It appears to be a US term. Or maybe I'm just ignorant. 1. utensils, as knives, forks, and spoons, used at the table for serving and eating food. 2. dishes or containers for the table that are more or less flat, as plates and saucers (source: the internet)

speps 8y ago

Follow-up post [1] with explanation of "ramp metering" and "sprinklers". [1] https://blog.plover.com/addenda/201804.html https://blog.plover.com/addenda/201804.html

draw_down 8y ago

Well, some mysteries are bigger than others.

mojomark 8y ago

At 5AM, as I sit waiting for a traffic light on a deserted stretch of road during my morning commute, glaring tempestuously at the nearby redlight camera, I wonder how we've gotten to driverless cars before getting to 'smart' intersection signaling systems that know there is a lone commuter patiently waiting to pass.

steindavidb 8y ago
It has to do a lot with reliability and cost. A smart car has a lot of expensive sensors and an expected life of a few years with regular maintenance. There's also a huge market opportunity around smart cars. Those cabinets can last decades, in all conditions, with minimal upkeep. Adding sensors decreases reliability and increases maintenance cost. There isn't usually an appetite to put traffic signal upgrades or extra maintenance headcount in city budgets for non-critical infrastructure upgrades, so the financial incentives to innovate are more limited as well.
- mojomark 8y ago
  Thanks - interesting. I know traffic pattern/flow models and studies can be extremely complex. However, from the perspective of a 'dumb' commuter, it seems like the investment in smarter traffic signals would be offset by global savings from/economic benefits of reduced congestion (e.g. idle bus transit fuel/maintenance savings or generally increased standard of living and economic imprivements due to increased traffic flow).
  - kqr 8y ago
    It is useful to talk about both inefficiency (the thing you point out) and exploitability (the ability for any individual actor to make useful amounts of money out of fixing the inefficiency.) Unless an area is both inefficient and exploitable, it is plausible that it will go unfixed for a long time. When you start viewing it in those terms, you find obvious inefficiencies everywhere.
dmckeon 8y ago
I wonder if the transition from human-driven vehicles to self-driving will bring a resurgence of traffic circles in the US as an intersection that can readily support any mixture of self-driven and human-driven.