City Traffic Lights - PLCS.net

Johnny Rotten · January 14th, 2005, 04:26 PM

Ok, the city I live in is growing. It has been for several years. Our Local Utility is working on sychronizing all the traffic lights.

You all know the story, wait almost 5 minutes (it seems like 1/2 hour) to get a green light. A massive amount of vehicles go 200 feet, only to hit 3 red lights in a row. 10 minutes and you have gone 2 Kilometers (80% of a mile).

The Local Utility is running fibre optics or thinking about it. What is a faster better way? Why not D0-06 AA/AR's at each intersection, do a 2 wire communication, done?

I really don't care, just wondering.

Oh yes, did I mention my shredder, baler, compactor work? LOL.

Johnny

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elevmike · January 14th, 2005, 05:08 PM

I'm not a traffic light expert, but I sure hope they dont use standard PLCs for real traffic lights..

Terry Woods · January 14th, 2005, 05:45 PM

"...I sure hope they dont use standard PLCs for real traffic lights."

Why? Or rather, why not?

As cheap as they are, several could be installed in redundant fashion.

There can be communication between intersections and the home office.

If any PLC fails, the home office knows.

When all have failed the last lights could go to a mechanically driven all-way stop mode (all reds flashing).

Why not?

elevmike · January 14th, 2005, 06:56 PM

Terry,

One could purchase a typical ready make traffic light controller for about $50.00. That's about $60.00 less then my faveriot "cheap" plc..AD-05. Then to boot the thing requires no programming...

Why?? My tax dollars is why..

http://www.trafficlights.com/plist.htm

EDIT: Oh..never mind thoes are for simulations or displays... bonkhead

Johnny Rotten · January 14th, 2005, 07:05 PM

I think we should just go back to monkeys. Not that monkeys ever did coordinate traffic, but it sure would be nice to see once in awhile.

Someone delete this posted subject.

John

Thomas Sullens · January 14th, 2005, 08:22 PM

Johnny I think it`s a good idea. With a plc and all the sensors on red lights anymore. They could do a little thinking for them selves. Like if no cars on 3 sides and lights red where car present turn GREEN . Think of the gas it would save. beerchug
Then make them wireless to cummunicate with each other less traffic on street A than B redirect traffic. All 4 lanes stopped there has been a wreck CALL THE POLICE . Count the # of cars through an intersection that way the State won`t have to pay someone to set there and count cars, but then who ever lost in the governors race might not have a job!

Johnny Rotten · January 14th, 2005, 08:52 PM

I don't know what a State or Governers Race is, but I will send a letter to Parliament to make wireless monkeys mandatory.

We could feed the cute little guys beers on weekends, if they behave. HMI's up high, so they could collaborate, and stay out of the snow.

As long as they don't poop on our cars.

John

jvdcande · January 15th, 2005, 07:20 AM

Quote:

10 minutes and you have gone 2 Kilometers (80% of a mile).

So, if I read this correctly, a Canadian mile - a measure I've never heard about - seems to be 2500m long???

testsubject · January 15th, 2005, 08:11 AM

Didn't they use monkeys for the traffic lights on the Flintstones?

elevmike · January 15th, 2005, 08:41 AM

Johnny,

Download Convert

In the mean time dont apply for a job with NASA on the Mars lander missions....They also screwed up a conversion that resulted in a crash on the red planet....

Lancie1 · January 15th, 2005, 08:21 PM

Fellows,

I would not recommend a PLC for traffic light control, BUT what about a dedicated special-purpose computer on a chip (same type now used to safely run automobiles) that has been programmed to MAXIMIZE the flow of traffic by using photodetectors looking down each oncoming street? After studying traffic lights here in the U.S., I have concluded that NONE of them are programmed primarily for the driver's needs. Instead, like Mike said, they are the low-bidder solution for "safe" traffic flow. No city traffic engineer has been told to get the most cars thru any specific intersection. The city has nothing to gain in promoting speed, instead, they are only concerned about preventing pile-ups. I think that BOTH functions could be achieved with the correct programmed computer in each light, and the proper sensors to determine the flow rate in each lane. Sadly for us drivers, there is no one to promote this idea.

kakarat · January 28th, 2005, 06:35 PM

SORRY TO BRING THIS TOPIC BACK FROM THE DEAD...
THX FOR THE LINK TO "CONVERT"
NICE ONE IT IS INDEED.
CHEERS

gbradley · January 28th, 2005, 09:00 PM

I think he mean't that a killometer is 80% of a mile.
Although it's closer to 62% of a mile??

danatech · January 28th, 2005, 11:02 PM

yeah, but he coulda been talking "canadian" percentages, too!

grouch

Johnny Rotten · January 29th, 2005, 07:33 PM

Ok, enough, I act like an idiot at times. I was stuck on the 2.5 centimeters = 1 inch as I usually use that every day. Why not 2.5 kilometers = 1 mile? Oh well, the glass(s) of wine was (were) nice. Have a great day.

Johnny

January 14th, 2005, 05:08 PM	#2
elevmike Member Join Date: Feb 2004 Location: Detroit, MI Posts: 4,012	I'm not a traffic light expert, but I sure hope they dont use standard PLCs for real traffic lights.. __________________ If you think you can do a thing or think you can't do a thing, you're probably right.... Henry Ford

January 14th, 2005, 06:56 PM	#4
elevmike Member Join Date: Feb 2004 Location: Detroit, MI Posts: 4,012	Terry, One could purchase a typical ready make traffic light controller for about $50.00. That's about $60.00 less then my faveriot "cheap" plc..AD-05. Then to boot the thing requires no programming... Why?? My tax dollars is why.. http://www.trafficlights.com/plist.htm EDIT: Oh..never mind thoes are for simulations or displays... bonkhead __________________ If you think you can do a thing or think you can't do a thing, you're probably right.... Henry Ford Last edited by elevmike; January 14th, 2005 at 07:00 PM.

January 14th, 2005, 08:22 PM	#6
Thomas Sullens Member Join Date: Feb 2004 Location: Idabel, Ok Posts: 390	post Johnny I think it`s a good idea. With a plc and all the sensors on red lights anymore. They could do a little thinking for them selves. Like if no cars on 3 sides and lights red where car present turn GREEN . Think of the gas it would save. beerchug Then make them wireless to cummunicate with each other less traffic on street A than B redirect traffic. All 4 lanes stopped there has been a wreck CALL THE POLICE . Count the # of cars through an intersection that way the State won`t have to pay someone to set there and count cars, but then who ever lost in the governors race might not have a job!

January 15th, 2005, 08:11 AM	#9
testsubject Member Join Date: Feb 2004 Location: Chicago, Il Posts: 748	Didn't they use monkeys for the traffic lights on the Flintstones? __________________ If you never encounter anything in your community that offends you, then you are not living in a free society. Kim Campbell Former Canadian Prime Minister

January 28th, 2005, 06:35 PM	#12
kakarat Member Join Date: Nov 2004 Posts: 8	SORRY TO BRING THIS TOPIC BACK FROM THE DEAD... THX FOR THE LINK TO "CONVERT" NICE ONE IT IS INDEED. CHEERS __________________ da newb of the year



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January 14th, 2005, 05:45 PM	#3
Terry Woods Member Join Date: Apr 2002 Posts: 3,170	*"...I sure hope they dont use standard PLCs for real traffic lights."* Why? Or rather, why not? As cheap as they are, several could be installed in redundant fashion. There can be communication between intersections and the home office. If any PLC fails, the home office knows. When all have failed the last lights could go to a mechanically driven all-way stop mode (all reds flashing). Why not?

January 14th, 2005, 07:05 PM	#5
Johnny Rotten Member Join Date: Dec 2004 Location: Ontario, Canada Posts: 156	I think we should just go back to monkeys. Not that monkeys ever did coordinate traffic, but it sure would be nice to see once in awhile. Someone delete this posted subject. John

January 14th, 2005, 08:52 PM	#7
Johnny Rotten Member Join Date: Dec 2004 Location: Ontario, Canada Posts: 156	I don't know what a State or Governers Race is, but I will send a letter to Parliament to make wireless monkeys mandatory. We could feed the cute little guys beers on weekends, if they behave. HMI's up high, so they could collaborate, and stay out of the snow. As long as they don't poop on our cars. John

January 15th, 2005, 08:21 PM	#11
Lancie1 Lifetime Supporting Member + Moderator Join Date: Jul 2003 Location: Alabama Posts: 7,235	Fellows, I would not recommend a PLC for traffic light control, BUT what about a dedicated special-purpose computer on a chip (same type now used to safely run automobiles) that has been programmed to MAXIMIZE the flow of traffic by using photodetectors looking down each oncoming street? After studying traffic lights here in the U.S., I have concluded that NONE of them are programmed primarily for the driver's needs. Instead, like Mike said, they are the low-bidder solution for "safe" traffic flow. No city traffic engineer has been told to get the most cars thru any specific intersection. The city has nothing to gain in promoting speed, instead, they are only concerned about preventing pile-ups. I think that BOTH functions could be achieved with the correct programmed computer in each light, and the proper sensors to determine the flow rate in each lane. Sadly for us drivers, there is no one to promote this idea.

January 28th, 2005, 11:02 PM	#14
danatech Member Join Date: Mar 2004 Location: ohio Posts: 44	yeah, but he coulda been talking "canadian" percentages, too! grouch

January 29th, 2005, 07:33 PM	#15
Johnny Rotten Member Join Date: Dec 2004 Location: Ontario, Canada Posts: 156	Ok, enough, I act like an idiot at times. I was stuck on the 2.5 centimeters = 1 inch as I usually use that every day. Why not 2.5 kilometers = 1 mile? Oh well, the glass(s) of wine was (were) nice. Have a great day. Johnny

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