they must get paid extra to make horrible decisions, I haven't seen one traffic light timing change they've made that's been beneficial to anybody

9/20/2007 8:08:13 AM

dont hate

9/20/2007 8:09:12 AM

when they make my commute 20-30 minutes longer than it should be, it's not only hatin' time, it's damn near stabbin' time

9/20/2007 8:10:40 AM

dont live so far away

9/20/2007 8:16:20 AM

agreed. shit must be MUCH harder than it looks.

i don't see why they can't build some more intelligence into those traffic lights.

but yeah,

Quote :

"dont live so far away"

9/20/2007 8:17:33 AM

its pretty complicated depending on the system and level of coordination

9/20/2007 8:18:12 AM

Yeah, designing those systems can get very complex. Besides, the best designs will always be negated by people who can't drive their way out of a wet paper bag.

9/20/2007 8:25:24 AM

how come they only change the lights that work good and not the lights that work bad?

9/20/2007 10:59:01 AM

You can look at practically any part of anything manmade around you and think 'some engineer was frustrated while designing this.' It's a little human connection.

9/20/2007 11:01:48 AM

I've never understood this shit either.. I don't know how many times I see lights that are close together in a city (every block or so, dur de dur) that are damn near timed perfectly to stop you at each light, even though nobody is coming any other direction. Seems a hell of a lot more efficient to just let ppl go on thru

9/20/2007 11:02:09 AM

After taking CE 305(Traffic Engineering) last semester, signal timing was one of the last things we did, and it was one of the most difficult things to do. However, with most lights close together on the same stretch of road(we'll say going Northbound, downtown). If you enter downtown and the light turns green, there is a speed at which you can drive and hit all green lights. Sometimes that speed is (way)under the speed limit, sometimes it's a bit faster than the speed limit.

It just depends on the length of road, and the average volume of traffic that road sees daily. If you wanna see what it's all about, take CE 305.



[Edited on September 20, 2007 at 11:35 AM. Reason : more]

9/20/2007 11:34:00 AM

they need to implement some type of much more complicated/thorough sensor system to know not only what cars are at the intersection but to also know the volume of cars approaching and how far away they are, etc. Seems like it could be a lot more efficient if the system had more data to work with.

I haven't taken the class you're talking about but I did do a project for writing a PLC program to handle all the different sensors and shit.. it isn't easy by any means, and we were working with a very simple intersection

[Edited on September 20, 2007 at 11:38 AM. Reason : asdf]

9/20/2007 11:37:34 AM

Quote :

"they need to implement some type of much more complicated/thorough sensor system to know not only what cars are at the intersection but to also know the volume of cars approaching and how far away they are, etc. Seems like it could be a lot more efficient if the system had more data to work with."

Some places use IR sensors, very few use radar, most use the coil of wire on the ground, and as your metal framed car sits in the area, the change in flux trips the signal.

9/20/2007 11:40:19 AM

Quote :

"I haven't seen one traffic light timing change they've made that's been beneficial to anybody "

it's really good in Pittsburg

9/20/2007 11:40:58 AM

The worst is the synchronized lights on Avent Ferry at the Lake Dam intersection and Athens Dr. split.

It pisses me of SOOO much when i go past the athens light then get stuck at a red at Lake Dam with no cars present b.c the athens light changed to Red behind me.

9/20/2007 11:41:36 AM

as your metal framed car sits in passes through the area

9/20/2007 11:55:39 AM

woo bureaucrats

9/20/2007 12:27:39 PM

they're mostly drunken Irishmen. I mean, look at Boston.

9/20/2007 12:30:02 PM

I lost all faith in traffic engineers when Crossroads went up.

Quote :

"I've never understood this **** either.. I don't know how many times I see lights that are close together in a city (every block or so, dur de dur) that are damn near timed perfectly to stop you at each light, even though nobody is coming any other direction. Seems a hell of a lot more efficient to just let ppl go on thru"

The people that sell gas/oil lobby the local governments heavily to ensure you run half your gas out idling at red lights.

I don't think I've ever been down that stretch of 64 between US1 and 55 without hitting every single light.

[Edited on September 20, 2007 at 1:26 PM. Reason : -]

9/20/2007 1:22:36 PM

i knew a kid in high school that got paid $13/hr to sit in a lawn chair at an intersection and record how many cars stopped at the stoplight.

9/20/2007 1:23:26 PM

Quote :

"I don't think I've ever been down that stretch of 64 between US1 and 55 without hitting every single light."

I honestly think those lights are UNsynchronized. To be a major expressway into Raleigh I always seems to hit a proportionally more lights then you would expect on a major roadway. All of the lights are at dinky secondary roads b.c all the major intersections have appropriate on/off ramps like at NC 55 and the start of Davis Dr.

My only thought could be that they are trying slow down traffic from going 70 mph into Cary.

[Edited on September 20, 2007 at 2:02 PM. Reason : l]

9/20/2007 2:02:18 PM

Quote :

"The people that sell gas/oil lobby the local governments heavily to ensure you run half your gas out idling at red lights."

you got any articles on this? It makes sense from their standpoint....I guess. I just want to read more about it.

9/20/2007 2:28:55 PM

I was just joking.

[Edited on September 20, 2007 at 2:30 PM. Reason : but I wouldn't be surprised these days.]

9/20/2007 2:30:35 PM

wasted time is bad for the economy in general. especially in the case of people who make deliveries, drive taxis, or otherwise drive as part of their jobs. lower economic output means less tax dollars collected by the government, which gives them incentive to get people where they're going faster (but safely so money isn't wasted on emergency services unnecessarily).

9/20/2007 3:29:10 PM

the only stoplight that pisses me off is the one on hillsborough and the meredith entrance/exit, there will be one car drive up to it and stop up to 50 cars going along with the timed green lights on hillsborough.

9/20/2007 4:54:49 PM

They really do need to work on the red light timings on US 64 btw Lake Jordan and Cary

9/20/2007 4:56:18 PM

Quote :

"they need to implement some type of much more complicated/thorough sensor system to know not only what cars are at the intersection but to also know the volume of cars approaching and how far away they are, etc. Seems like it could be a lot more efficient if the system had more data to work with. I haven't taken the class you're talking about but I did do a project for writing a PLC program to handle all the different sensors and shit.. it isn't easy by any means, and we were working with a very simple intersection "

Its a nice idea, but that would cost some major $$$, and if one sensor goes down then the whole thing will get screwed up...

Seriously folks, figuring out timing signals that work is pretty goddamn hard (I have friends who do this), so if you think its so bad, why don't you try it? You are NEVER going to get every single car to avoid a red light, and because some roads are congested so bad priority goes to the 'needs of the many', not the 'needs of the few'. All of these advanced ideas cost alot of money and wont work perfectly either... The reason why you get stuck at many redlights in downtown is because they are all on timed intervals, which works well in that area for daytime peak hours that see the most traffic (again with the many vs few thing).

You can do alot to help yourself with redlights too: here are some hints
a) watch the crosswalks they can clue you in as to how long a green light will remain green.
b) dont drive much on small roads, you may think you are getting a shortcut but everytime a minor road intersects a major road rest assured the major one is going to get the vast majority of green light time (because it has more cars... many vs few).
c) notice *where* the coils are in the road, if you are idiot and stop past the white line chances are you are not setting off the detector!
d) know alternate routes that you can pick based on the light situation you see ahead of you.

9/20/2007 5:15:44 PM

Quote :

"because some roads are congested so bad priority goes to the 'needs of the many', not the 'needs of the few'"

Except for on US64 where I always manage to get caught for 5 out of 6 stoplights btw lake jordan and Cary in order to let one car turn left.

9/20/2007 5:50:08 PM

Signals for left turn lanes are a bitch. In this project we did, after going through all the calculations and basing our numbers on recorded data, our left turn lane had 3 seconds of green.

9/20/2007 6:16:02 PM

yeah the left turn signal coming from downtown on Western Blvd at the intersection of AVent ferry is rly shitty

9/20/2007 8:22:11 PM

^^^^

e) dont live so fucking far away

9/20/2007 8:23:39 PM

Quote :

"because some roads are congested so bad priority goes to the 'needs of the many', not the 'needs of the few'."

They've recently added a new light at a new shopping built near me. It backs up traffic for a mile in one direction to let out four cars.

9/20/2007 8:29:51 PM

unless you live in DC, Atlanta, LA or NYC, you have no right to bitch about anything traffic related

9/20/2007 9:08:28 PM

NYC?

no


the others, yes... and add Houston

9/20/2007 9:09:30 PM

the lights are actually pretty good where i live

9/20/2007 9:10:16 PM

agreed, but nyc can be nasty.


fuck it, take the train.

9/20/2007 9:24:15 PM

Quote :

"You are NEVER going to get every single car to avoid a red light, and because some roads are congested so bad priority goes to the 'needs of the many', not the 'needs of the few'."

I don't think that getting every single car to avoid a red is an achievable goal, but that doesn't mean that they shouldn't at least work toward a goal of "a majority." I don't expect to hit all the lights green when driving down secondary roads, but I expect to catch over 50% green when on main thoroughfares.

And I'll echo what everyone else has said. Currently the needs of the few are superseding the needs of the many. I don't know how many times I've seen the scenario where the flood gates from one red light open just for a light a block away to turn red. Why? Because someone just pulled up to that intersection (zero wait time for them). Makes it even worse when they were just going to turn right anyway.

At the very least you would think that it wouldn't be hard to sync up lights that are less than a block away such that the scenario where one light turns green just in time for the next light to turn red. The problem is the sensors. The light determines that no one is coming on the main road because they are all stopped up a block away. One car pulls up to the intersection and is given priority since no one is supposedly coming from the other direction.

I guess it could be worse. I remember one intersection in Greensboro (the old way to merge from 421 N onto 40 W) where there were two lights in a row, about 3 car lengths apart. You were in trouble if you wanted to make a left. The second light would give a green arrow but only when the first light was red. So you would have to wait on the red light, watch the second light give the green arrow for no one, once the first set turns green you go to the second light (now red), and finally go when the second set changed back to give the green arrow. [/ramblings]

[Edited on September 21, 2007 at 7:35 AM. Reason : -]

9/21/2007 7:29:55 AM

informative thread. 10/10

9/21/2007 7:30:59 AM

there's a specific light up here that the DOT thinks that a person can run better than their algorithms


so i shit you not,

during peak times, there's a cop sitting in his car, where he can see the intersection, with two long strings tied to the control box...

so he can sit in his car and do it like a marionette

9/21/2007 7:33:07 AM

well honestly it's only the one light timing in fuquay they fucked up and the lake wheeler/hilltop needmore light timing that's fucked up

my other problems are they need to give northbound traffic at the lake wheeler/penny rd intersection like 10-20 seconds of green before they give the southbound people a green so the annoying fuckers that turn left onto penny can not hold up traffic for a mile+

also, the idiots added a completely worthless right turn lane at the lake wheeler/tryon intersection when it's the left turn people who back that shit up all the way back to goddamn penny road

it's just a complete and utter clusterfuck that could be solved if one of those fucking engineers spent an hour at peak times at those fucking lights

9/21/2007 7:44:03 AM

when and if i get my video equipment, i want make a documentary about the traffic lights in raleigh

9/21/2007 8:31:22 AM

^Rent that shit from DH Hill

9/21/2007 9:13:48 AM

apart from synchronization issues, the other issue I think needs to be addressed is green-time and arrow priority. In most of Cary, for example, driving around Maynard or Cary Parkway, synchronization is not an issue because the lights are spaced pretty far apart. The issue with several of those lights is the amount of red vs. green time and how the turn lanes and arrows are used.

two examples:
the intersection of Maynard and Chapel Hill. Both streets, I would estimate, carry the same volume of traffic, even though Maynard is 2 lanes each way and Chapel Hill is 1 lane. To compensate for this, the light on Chapel Hill stays green much longer than the light on Maynard. So if you're on Maynard trying to go straight, the light will stay green literally for seconds, allowing only a few cars though. Then it will stay green for a minute or more on Chapel Hill. Even worse is if you want to use one of the turning lanes off of Maynard onto Chapel Hill, both of which use only arrows. One, the lanes are too short and they get backed up into the main traffic, and two, the arrows stay green for even less time than the main lights. I drive through that intersection for lunch a lot, and usually only 3-4 cars get though on a green arrow, when there are 15+ waiting behind them.

Second, the intersection of Cary Parkway and High House. I think they might have fixed this, but I used to avoid this one like the plague during high traffic times (morning, lunch, after work). Both roads are 4 lane and very busy. Both lights would get roughly the same amount of green-time, but the cycles were just way too short. I'm sure traffic engineers study how long it takes traffic to get up to speed and flow naturally, and I'm sure they find that a lot of time is wasted when people go from a stop to normal speed, and vice versa. So for a light with lots of traffic, it's the worst thing to go green, then just as soon as traffic through the light reaches a normal speed, go red again. This just sends waves back through the line. On Cary Parkway/High House, I believe they have lengthened the cycle time by a lot, so even though the red-lights are longer, when the light is green, the whole line of traffic gets up to speed and more people get though.

9/21/2007 9:44:50 AM

CE 305 With Bob Foyle FTW

9/21/2007 1:43:47 PM

Quote :

"One, the lanes are too short and they get backed up into the main traffic"

That sucks, but sometime you can really extend the left turn holding lane because of whatever reason(mainly lack of space).

Seriously though, email the city planners/city engineers about some of these problems in a professional manner. They like the input and will have a better time trying to solve problems if they know where problems are.

9/21/2007 1:49:39 PM

[Edited on September 21, 2007 at 1:51 PM. Reason : ]

9/21/2007 1:50:25 PM

Quote :

"some roads are congested so bad priority goes to the 'needs of the many', not the 'needs of the few"

MLK blvd > blount st



...guess which one has red more often?

9/21/2007 1:50:30 PM

Quote :

"One, the lanes are too short and they get backed up into the main traffic"

What makes this worse is that in Cary there are a lot of lights that follow an alternate cycle than the rest of the entire USA. Traffic that is going straight gets the light first, then they stop and traffic taking a left at an intersection get the light. So if the left hand lane is backed up into main traffic no one goes.

Seriously, what's up with the reverse cycle? There's been a few times when I've waited on a green arrow, the main traffic got the green, and I'm sitting there thinking that the light just didn't turn green for me during that cycle. Nope, it just saves me for the end.

[Edited on September 21, 2007 at 1:55 PM. Reason : -]

9/21/2007 1:53:25 PM

they have to get paid extra to fuck up intersections, there's no way that fuck-ups of this magnitude and quantity are the results of simple poor planning

10/25/2007 8:17:41 AM

WHAT CRITICS

10/25/2007 8:44:08 AM