Automated traffic light control systems (was: Re: EP354: The Caretaker)

[matweller]

My apologies, Unblinking, I'm guilty of reading Dem's response and assuming without reading your full thread.

[WARNING: Complete temporary topic switch]

Funny you should be in that business, though, it's been in my mind a lot lately. I have no objection to the kind of traffic devices you describe, but I have been trying to figure out where I stand on the punitive ones they use to mail you tickets for speeding or running a red light. There's no human judgement involved, no opportunity to plead your case, no warnings, and very limited recourse of any kind -- just pay the bill and who cares about your problems? It makes me wonder what direction our law enforcement is taking -- do they really intend to 'serve and protect' or are they becoming just a fund raising arm of the government. I mean really, we live in a day and age where 10 extra lines of code in your car's computer could control a limiter in your car that would make you keep your speed within certain parameters. That being the case, choosing to devote tax dollars to ticket-generating devices instead really just makes the state police program a computer generated bake sale, no?

Honestly, I don't know. Like I said, I've been mulling it over a lot lately with a list of things our society seems to be doing to punish people rather than using less resources to just eliminate the problems. But it's only tangentially related, so I apologize for the interruption.

[Unblinking]

Funny you should be in that business, though, it's been in my mind a lot lately. I have no objection to the kind of traffic devices you describe, but I have been trying to figure out where I stand on the punitive ones they use to mail you tickets for speeding or running a red light. There's no human judgement involved, no opportunity to plead your case, no warnings, and very limited recourse of any kind -- just pay the bill and who cares about your problems? It makes me wonder what direction our law enforcement is taking -- do they really intend to 'serve and protect' or are they becoming just a fund raising arm of the government. I mean really, we live in a day and age where 10 extra lines of code in your car's computer could control a limiter in your car that would make you keep your speed within certain parameters. That being the case, choosing to devote tax dollars to ticket-generating devices instead really just makes the state police program a computer generated bake sale, no?

Honestly, I don't know. Like I said, I've been mulling it over a lot lately with a list of things our society seems to be doing to punish people rather than using less resources to just eliminate the problems. But it's only tangentially related, so I apologize for the interruption.

Automatic traffic enforcement is still at this moment is a legally sticky area, at least in the US.  They can't be used in some states, including Minnesota (where I live).  I think that the primary reason that they are banned here is that people consider it a flawed system in which you cannot confront your accuser.  At this point I think some individual states have banned these, but by no means all of them.

What people are willing to accept has a lot to do with individual cultures as well.  I know of systems deployed in the UK which track license plates over long distances, and datamine to look for suspicious movements that might be used as evidence, primarily for trying to prevent terrorist acts.  I think that people in the US would freak out if something like that were deployed here, even post-9/11.  

[Dem]

I think our long distances are a lot shorter than yours - we can do the whole country in a few hours! Of course we can also get lost for days in the back streets of Hackney or the country lanes of south Devon so tracking can be a bit of a bonus. Unless it finds the annoying pensioners you've being trying to shake off all week, then it's a pain 

[Devoted135]

I think our long distances are a lot shorter than yours - we can do the whole country in a few hours! Of course we can also get lost for days in the back streets of Hackney or the country lanes of south Devon so tracking can be a bit of a bonus. Unless it finds the annoying pensioners you've being trying to shake off all week, then it's a pain 

Distances are definitely relative. For example, both Alaska and Texas are larger (by square kilometers) than France and Spain, and there are four states larger than Germany. Makes it a lot harder to visit friends when they move 3,000 miles (4,800km) away! Then again, the New Englanders I've met are horrified when they realize how long it takes to drive between states anywhere else in the country.

[InfiniteMonkey]

Distances are definitely relative. For example, both Alaska and Texas are larger (by square kilometers) than France and Spain, and there are four states larger than Germany. Makes it a lot harder to visit friends when they move 3,000 miles (4,800km) away! Then again, the New Englanders I've met are horrified when they realize how long it takes to drive between states anywhere else in the country.

Yeah... but we're prettier out here......

(how's THAT for an unbiased, neutral, un-opinionated comment  ?)

[Unblinking]

I think our long distances are a lot shorter than yours -

True, true.  But I don't think that's the difference here.  When I was talking about long-distance tracking I just meant that there's a centralized system that's following cars as they move from city to city and country to country, regardless of how far aparts the cities and countries are. 

[Dem]

I think our long distances are a lot shorter than yours -

True, true.  But I don't think that's the difference here.  When I was talking about long-distance tracking I just meant that there's a centralized system that's following cars as they move from city to city and country to country, regardless of how far aparts the cities and countries are. 

Oh the paperwork!

[CryptoMe]

The more longstanding technology that we are trying to outdo is magnetic loops.  Sometimes you see a rectangular shaped cut in the pavement--that is where the magnetic loop is, and it detects the metal of the car stopped on top of it (hint:  If you want to get your arrow soon, you can do so faster if you stop directly on top of that loop).

The car I drove in grad school did not have enough metal to trigger the magnetic loop system. It was really, really annoying, because there were lots of places where the light wouldn't change unless the magnetic loop system was triggered. So, when driving late at night, I would have to jump out of the car and press the pedestrian walk signal to get the light to change. Not the most fun, especially in a rough neighbourhood...

I grew to hate those magnetic loops 

[Kaa]

I heard that if you're in or on a vehicle with not enough metal to trigger the loop, get yourself one of those powerful rare-earth magnets and tape it under your vehicle. Car, bike, whatever. When you drive over the loop, you won't need the metal to trigger it.

Don't know if that would work, but it sounds reasonable.

[Unblinking]

The more longstanding technology that we are trying to outdo is magnetic loops.  Sometimes you see a rectangular shaped cut in the pavement--that is where the magnetic loop is, and it detects the metal of the car stopped on top of it (hint:  If you want to get your arrow soon, you can do so faster if you stop directly on top of that loop).

The car I drove in grad school did not have enough metal to trigger the magnetic loop system. It was really, really annoying, because there were lots of places where the light wouldn't change unless the magnetic loop system was triggered. So, when driving late at night, I would have to jump out of the car and press the pedestrian walk signal to get the light to change. Not the most fun, especially in a rough neighbourhood...

I grew to hate those magnetic loops 

Really?  That's interesting.  I didn't think that they were actually dependent on the metal, but on something massive interfering with the magnetic flow.  (But I'm no expert at the magnetic loops, of course) I know that magnetic loops sometimes have trouble with semi trucks, but that's because the bottom of the trailer is so far off the ground that sometimes it doesn't trigger unless the wheels are on top of the loops.  Usually when I hear people complain about them though, it's motorcyclists, hadn't heard of a car that had trouble triggering them.

[CryptoMe]

It was a Geo Metro. About the only thing metal on it was the 1.0 L engine, which was tiny. And the car itself was very light - two of us picked it up and "corrected" my parking on a tight corner around the Mall in Washington DC once. The other guy thought I was nuts when I suggested it, and then couldn't believe how easy it was to pick up. So the car didn't have enough metal to set of the magnetic sensors, nor enough weight to set off the mass sensors. It got great gas milage though (50 mpg highway).

[Fenrix]

It was a Geo Metro. About the only thing metal on it was the 1.0 L engine, which was tiny. ... So the car didn't have enough metal to set of the magnetic sensors, nor enough weight to set off the mass sensors.

FWIW, mass sensors haven't been used in decades, and was generally experimental and also one of the first technologies replaced by the transfer from mechanical to solid state. Back in ye olden times, most traffic signals just ran on fixed time. Now, it's mostly in-pavement electromagnetic flux loops and machine vision video imaging. Following far behind is microwave detection. New emerging technologies include electromagnetic flux pucks that communicate via bluetooth and thermal imaging cameras.

Should you ever have the problem again with detection, aim to put the most metallic part over a corner of the rectangular loop, as the electromagnetic field is stronger there. If it's a figure 8 loop, aim for the middle, as the field is substantially stronger in the center. Also, stop at the stop bar. I will never cease to be amazed by folks who pull a car length past the stop bar and get angry about the detection not working.

I would start troubleshooting by adjusting the sensitivity of the detection device. I like to keep the sensitivity as high as possible without picking up errant calls from adjacent lanes. False calls from adjacent lanes are some of the biggest problems with this kind of detection, and is to be avoided when you have a left turn and through lane adjacent to one another. Compound this with the fact that these are outdoor facilities that experience heat, cold, and critters chewing at the shielding, and splices that deteriorate over time. So you have to balance sensitivity against electronic chatter. If jiggering the sensitivity doesn't work, start checking splices, cutting them out and resplicing and resealing. Some swear by soldering the splices, others hate it. Different sealants have different weathering and aging properties. Make sure the pull boxes in the ground drain properly, and that the system has decent grounding.

TL;DR - Detection sucks, fairly hard. Every method of detection has different ways of sucking.