Traffic light switches

LTDHO · 06-03-2006, 01:22 PM

I thought this was common knowledge, but from what I have been seeing recently, it is clearly not the case.

FACT: Did you know there are car sensors under the road at intersections controled by lights?

Twice last week I saw drivers getting mad because the didn't get a green arrow because they had passed the sensors and were creeping over the line.

This is why creeping (impatience) doesn't make lights change quicker!!!

I always stop on these for two very good reasons. 1. so lights change quicker and 2. to leave safe space infront of my car.(gives motorbikes space too)

agony · 06-03-2006, 01:24 PM

yes you would think so wouldnt you!

just the same as pressing the crossing button a hundred times doesnt mean anything.

GT-E · 06-03-2006, 01:46 PM

I had to get out of my car and tell a Tarago driver to move forward, as they were 20ft from the lines. This was after 5mins of waiting for them and to see if the 5 other cars in front of me did anything......

XA Coupsta · 06-03-2006, 02:05 PM

So do you need to keep the sensor active (by staying on it) or are they simply ones that you can pass over and then they are activated?

I knew they had road sensors but was unsure how they activate.

4.9 EF Futura · 06-03-2006, 02:07 PM

Yeah we're slowly moving away from under road sensors here and camera operated intersections are becoming more frequent.

For anyone in Adelaide, can do tours of the centre:

http://www.transport.sa.gov.au/trans...ontrol_cnt.asp

Wouldnt mind heading down there next time i get some annual leave... just to see the place... altho next holiday i take, cars will prob be extinct by then!

Lol - creep away all you like.. just be sure to stop on the sensor for a bit!

Oh.. some more cool stuff on the ACTS system in SA:

http://www.transport.sa.gov.au/trans...cts_system.asp

fiery · 06-03-2006, 02:08 PM

I think they forgot to put the sensors into anywhere when they did some of these lights here at Morayfield........ you can sit and sit and sit no matter how perfect you are to the sodden line........
drives me nuts...

:

merlin · 06-03-2006, 02:09 PM

I believe some are magnetic in their activation? I only know this as riders of certain makes of bikes strap a small strip of metal to the bottom of their fairing.

4.9 EF Futura · 06-03-2006, 02:15 PM

Quote:

Originally Posted by fiery

I think they forgot to put the sensors into anywhere when they did some of these lights here at Morayfield........ you can sit and sit and sit no matter how perfect you are to the sodden line........
drives me nuts...

:

They should be easy to spot... can see the black 'seam' where the plate is... altho that's probably only for intersections which have been retrofitted... may be different story if they're built in from day 1.

06-03-2006, 02:18 PM

Minor intersections don't have the switches.

AnthonyQLD · 06-03-2006, 02:21 PM

Quote:

Originally Posted by merlin

I believe some are magnetic in their activation? I only know this as riders of certain makes of bikes strap a small strip of metal to the bottom of their fairing.

Im pretty sure thats right, Sometimes when I ride my bike it will not activate the sensor

McobraR · 06-03-2006, 03:04 PM

Interesting, i thought they were weight activated (somethin like a minimum of 200kg), but thats just me

:

Dauphin · 06-03-2006, 03:19 PM

At the advanced driving course I did the guy told us that there are 20 feet of sensors at each red light to detect the presence of vehicles and that going back and forth over the line doesn't do anything.

I think sometimes they get confused or the programming gets confused for a moment as I was stuck in a huge line once when the fuel prices were about to jump about 20 cents a litre. A huge truck was at the light in front of us, sticking outover the line and I think it messed up the sensors as it was taking 4 times as long as usual. I got out of line, turned left and did a U-turn and went passed them all still waiting for the green light. I got to the BP just before the guy came out to change the price!

Other times it has skipped or missed a green turning light for some strange reason, so I don't know how the great mystery works exactly.

Sourbastard · 06-03-2006, 03:20 PM

Quote:

Originally Posted by 4.9 EF Futura

Yeah we're slowly moving away from under road sensors here and camera operated intersections are becoming more frequent.

For anyone in Adelaide, can do tours of the centre:

http://www.transport.sa.gov.au/trans...ontrol_cnt.asp

Wouldnt mind heading down there next time i get some annual leave... just to see the place... altho next holiday i take, cars will prob be extinct by then!

Lol - creep away all you like.. just be sure to stop on the sensor for a bit!

Oh.. some more cool stuff on the ACTS system in SA:

http://www.transport.sa.gov.au/trans...cts_system.asp

Ive worked in norwood traffic control before, the cameras are for traffic monitoring(By humans), but the piezoelectrics still do the main work in ACTS. The cameras are mostly for operators to note areas of congestion(Pinpointed by ACTS software usually), and change the traffic signal management software to alter the sequences and length of sequences as required to clear abnormal congestion(sometimes due to something like an accident, or a scheduled road event). This can be done on more then one intersection to clear a stretch of road. Can also be done for cops, ambulances and fire trucks to clear the road ahead of them in an emergency.

4.9 EF Futura · 06-03-2006, 03:24 PM

Quote:

Originally Posted by sourbastard

Can also be done for cops, ambulances and fire trucks to clear the road ahead of them in an emergency.

Yeah ive seen that in practical use. Seems to work quite well.

Hey - the glen osmond/hutt rd intersection - that bugger is still not sensored is it??

Sourbastard · 06-03-2006, 03:26 PM

unsure, not a road I take very often if at all. There are still many intersections being run by hard wired timed sequences.

The Monty · 06-03-2006, 05:35 PM

All you have to do is step on them while your walking past. It really annoys drivers when you do it when they are the only car on the road at night, and the lights go red on them for no-one.

MAD · 06-03-2006, 05:57 PM

Quote:

Originally Posted by The Monty

All you have to do is step on them while your walking past. It really annoys drivers when you do it when they are the only car on the road at night, and the lights go red on them for no-one.

They work on inductive loops which require a decent amount of metal (why some motorbikes dont trigger the sequence) to pass over it to create a small electric pulse by disrupting the magnetic feild in the coil embedded in the road.
So either you were wearing HEAVY steel boots, or it was a sheer coincidence that the light sequence was tiggered.

Read more here... http://www.humantransport.org/bicycl.../detection.htm

**Falcon Coupe** · 06-03-2006, 06:23 PM

The sensor near my place was not calibrated to pick up motorcycles, i used to sit there for 3 changes of lights then go through the red arrow, i don't know if the sensors detect weight or mass.

chevypower · 06-03-2006, 06:29 PM

many intersections even have sensors quite a few meters away back from the line to sense if there is multiple cars waiting, to change the lights quicker, you can cheat them by sitting further back if you are the only car, providing you are on the sensor - not sure what the exact requirements are thought, but we have done it...

coyote · 06-03-2006, 09:00 PM

Quote:

Originally Posted by fiery

I think they forgot to put the sensors into anywhere when they did some of these lights here at Morayfield........ you can sit and sit and sit no matter how perfect you are to the sodden line........
drives me nuts...

:

Yet to get a clean run with an average of having to stop at at least three of them.\

For those luckey enpough not to have to use them these four sets of lights are in the space of 500 m Qld transport Home of the smart state numberplates.

XD 351 Ute · 06-03-2006, 09:33 PM

We should be allowed to shoot the people that push the 'walk' buttons and then go across anyway without waiting for the lights................

Ed

AMT · 06-03-2006, 10:50 PM

I am sure they are weight activated because my brother and i did a early morning paper round when we where young and we used to lift the front wheel on our bikes and slam it down hard on the black thin lines and the traffic lights would change straight away... maybe there different now...?

Scott · 06-03-2006, 11:05 PM

Quote:

Originally Posted by nhanst

I am sure they are weight activated because my brother and i did a early morning paper round when we where young and we used to lift the front wheel on our bikes and slam it down hard on the black thin lines and the traffic lights would change straight away... maybe there different now...?

Nope, they are a piece of wire layed into a cut in the road surface which is then filled with sealing compound. Induction on the loop is monitored & when something metal (ferrous) get's close, the value changes.

Next time you have a steel rubbish bin lid handy, put it on the road loop & keep yourself entertained for hours. Nothing at all to do with weight.

ps - your pushy would do it to

Hunter · 06-03-2006, 11:45 PM

Yeah there's a sensor near work which is very very intolerant. If you're even 30 cm away from it, it won't work. Heaps of traffic congestion is caused by it yet nobody ever fixes.

I dunno why but Brisbane's traffic lights don't seem to be coordinated AT ALL. Some days you get absolute ИИИИty runs because of the lights not being synchronised. Like you'll get a green on one intersection but the intersection 50 m up the road is still red so all the traffic is held up because the lights ahead won't change for another 20-30 seconds. Its bloody stupid. And yes, there are many stretches with a half dozen of lights spread over a few hundred meters up here.

:

08-03-2006, 04:47 PM

Shopping trolleys work really well...

Maccas drive thrus have them at the start of the lane, and causes the drive thru high pitch beeps to go off. Go there 20 mins after they open/close on a quiet morning/night and ИИИИ off the workers inside. (I used to work at maccas and did this during a night out when i wasnt working)

AC/DC · 08-03-2006, 05:39 PM

I used to work for the council as an Electrician in Townsville, and we did many traffic "loops" as you call them. They simply cut a large rectangular shape in the road with a concrete saw, and then we used to push in about 6 turns of normal wire, , push it down hard with a bit of flat steel and then seal with liquid nails ( about 40 tubes per intersection )

The loop is then fed a small current , and it notices a change in the impedance when a steel object (car) is over it.

We used to check they were working with the steel bin from the truck, that had all the empty silastic tubes in it !

So..

1. The are definatley NOT operated by weight.
2. They need steel above them
3. Yep, they do stuff up, as the ground moves, or water or trucks stopping, they might open circuit, and then we used to come along and re cut them and do it over again.
4. In North Queensland in Summer it SUCKED doing traffic loops....

Thats the low down on traffic loops !

(p.s. A traffic light controller costs about $20 000 , , so if you lose it on an intersection, try not to hit the controller box )

AC/DC

AC/DC · 08-03-2006, 05:41 PM

pps... every intersection in Townsville has loops cut !

AC/DC

megsy · 08-03-2006, 06:11 PM

Quote:

Originally Posted by Ed

We should be allowed to shoot the people that push the 'walk' buttons and then go across anyway without waiting for the lights................

i was under the impression that during normal traffic hours whenever you pressed the walk button it didnt affect the traffic lights at all it just added a walk sign to the specific part of the program where the traffic was flowing the other way,

although this isnt the same for special pedestrian lights.

chief · 08-03-2006, 06:15 PM

Quote:

Originally Posted by BlackLS

Shopping trolleys work really well...

Maccas drive thrus have them at the start of the lane, and causes the drive thru high pitch beeps to go off. Go there 20 mins after they open/close on a quiet morning/night and ИИИИ off the workers inside. (I used to work at maccas and did this during a night out when i wasnt working)

My brother worked at Hungry Jacks for a while and the drive through is meant to take less thean 2 minutes. That never happened so at the end of the night take a steel bucket and just wave it over the sensor to bring down the average time in drive through.

Trevor 57 · 08-03-2006, 06:47 PM

Quote:

Originally Posted by XA Coupsta

So do you need to keep the sensor active (by staying on it) or are they simply ones that you can pass over and then they are activated?

I knew they had road sensors but was unsure how they activate.

The strips under the road are magnetic, and should keep working whether you drive forward over them or you stay on top of them, the metal of your car trips them.