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Traffic signal

Started by Tom89t, January 14, 2012, 01:01:45 AM

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roadfro

Quote from: jakeroot on July 16, 2018, 01:35:36 PM
Do you guys think this signal approach is MUTCD-compliant?

According to a Seattle city traffic engineer, this signal is compliant because the primary movement is the slight right at this intersection. However, the MUTCD indicates that two primary signal faces are required for any through movement. My interpretation of "through movement" is not the same as "major movement" (hence why I believe that term was ultimately removed in 2009 -- compare ~4D.15 in the 2003 edition, to 4D.11 in the 2009 edition). AFAIK, a "through movement" is anything that isn't a left or right movement. Even if that means slight right, such as here, that would disqualify it from being considered a "through" movement.

https://i.imgur.com/GQHWwJp.png

Late to the party here, but I agree with your assessment. If installed under 2009 MUTCD, this signal is not compliant with the minimum requirement of two signal heads for the through movement.

I also agree with what SignBridge said about having two signal heads for each signalized movement, especially for redundancy purposes. It's something Nevada does right.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.


ErmineNotyours

Quote from: jakeroot on July 16, 2018, 03:00:35 PM
The only previous time that I contacted a city (Renton, WA) about a missing through signal, they added one about a month later. I quoted the exact same section from the MUTCD.

Before -- After



Wow, you did that?  This used to be on my daily bus commute.  This intersection was reconfigured when Rainier Avenue was widened to add a BAT lane in the northbound direction.  An existing lane was taken away for this in the southbound direction.  This involved rebuilding a railroad overpass, so it was no small feat, but this was to provide a whopping three blocks of "exclusive" transit lane for the new Rapid Ride F line, the only exclusive footage on the whole line.  Initially, there were two through lanes on that part of the intersection, and thus two through lights.  The middle lane also turned left, so left and through traffic must happen simultaneously.  They untangled that by making the middle lane turn left only, but I noticed it was odd that there was now only one light for through traffic.  I hadn't noticed when the additional light came on.

Once they allowed for simultaneous through movements on 7th, the traffic backups for left turns got worse, especially when pedestrians want to cross on the crosswalk that the left turn crosses.  Bus rapid transit is supposed to include signal prioritization for buses, but this bus always waits at this light.  Metro's version of bus rapid transit is so skimpy and barely qualifies for the requirements.  Stop skipping is minimal, and off-board payments happen at only about half the stops.  Last week at a time of the day when the schedule was on 15 minute headways, my bus was at the lead of a four bus bunch right before it reached the end of the line.  I wanted to get a picture of all four buses crowded at the last stop, but the driver refused to go around the corner to enter the last stop, forcing all passengers to get off early.  Another bus did the same, and only two coaches reached the end.

If Renton is this responsive to traffic signal issues, perhaps I should tell them of a signal I walk by every day that has a left signal that erroneously turns green even when no cars are there.

jeffandnicole

Quote from: ErmineNotyours on July 18, 2018, 10:24:30 AM
If Renton is this responsive to traffic signal issues, perhaps I should tell them of a signal I walk by every day that has a left signal that erroneously turns green even when no cars are there.

It could easily be a bad sensor.  While their transportation crews may drive around every day, it can sometimes be a chance encounter that they notice or don't notice something.

Definitely give them a call or email!

jakeroot

#1853
Quote from: roadfro on July 18, 2018, 10:03:21 AM
Quote from: jakeroot on July 16, 2018, 01:35:36 PM
Do you guys think this signal approach is MUTCD-compliant?
...

https://i.imgur.com/GQHWwJp.png

Late to the party here, but I agree with your assessment. If installed under 2009 MUTCD, this signal is not compliant with the minimum requirement of two signal heads for the through movement.

Thanks. His dismissal is alarming. Any traffic engineer should be able to read that MUTCD section, and understand it as requiring two green orbs at any intersection with a straight movement. Even non-engineers would agree that having only one signal for a movement is a risky proposition. It wouldn't surprise me if he dismissed me because he doesn't want to fix it, or his head is stuck in the past. The old signal had three green orbs: https://goo.gl/TN5Xxe (summer 2008 GSV). This setup, minus the far left 4-section head and 8-inch heads, is identical to what the new signal should have looked like. I believe the current signal was installed in 2010. A while ago, but recently enough to require that extra signal head for the through movement.

Sorry if I sound kind of butthurt. Seattle has had some serious signal issues lately (too closely spaced, poorly placed relative to other intersection objects, not enough altogether, removing pole-mounted signals when switching to overhead signals (why not keep both?), etc); I want to help them fix these shortcomings to the best of my ability, by at least alerting them to basic MUTCD regulations. But for them to just weasel their way around the rule is just...annoying.

Quote from: roadfro on July 18, 2018, 10:03:21 AM
I also agree with what SignBridge said about having two signal heads for each signalized movement, especially for redundancy purposes. It's something Nevada does right.

I definitely agree. Redundancy is key. You never know when a signal might go out, and if common sense has taught us one thing, it's to not trust drivers at a burned-out light. Many Washington cities have started installing extra signals over the last ten years; it's quite encouraging. Even the DOT has been hopping on the bandwagon with some projects. Here's hoping the state might change our MUTCD to require additional redundancy at some point.




Quote from: ErmineNotyours on July 18, 2018, 10:24:30 AM
Quote from: jakeroot on July 16, 2018, 03:00:35 PM
The only previous time that I contacted a city (Renton, WA) about a missing through signal, they added one about a month later. I quoted the exact same section from the MUTCD.

Before -- After

Wow, you did that?  This used to be on my daily bus commute.

Yep, that were me. One of my lasting legacies! Lol. My mother used to work in Renton before moving to DC, so I spent a fair amount of time driving around the city. One day, while driving together to get lunch, we drove eastbound through that intersection (after it was reconfigured), and I knew something was wrong. So I emailed them, and they fixed it right up impressively fast. A great lasting impression, especially since they listened to my recommendation of placing the new signal on the mast, and not overhead.

jakeroot

#1854
This pole-mounted signal in Fife, WA is placed quite low to the ground, due to the pole being mounted slightly below ground level. The intersection is slightly elevated, but this signal pole doesn't seem to be. Oddly, the opposite direction's pole-mounted signal is mounted a bit higher than normal. Spin the GSV around a bit.

https://goo.gl/YpyDBM (Valley Ave @ Freeman Road)


roadfro

Quote from: jakeroot on July 19, 2018, 02:46:38 AM
This pole-mounted signal in Fife, WA is placed quite low to the ground, due to the pole being mounted slightly below ground level. The intersection is slightly elevated, but this signal pole doesn't seem to be. Oddly, the opposite direction's pole-mounted signal is mounted a bit higher than normal. Spin the GSV around a bit.

https://goo.gl/YpyDBM (Valley Ave @ Freeman Road)



It doesn't seem that low to me. But it might not be mounted at the minimum of 8 feet from sidewalk (or the pavement grade at the center of the roadway if there is no sidewalk) to bottom of signal housing [See MUTCD 4D.15]. The other pole/mast mounted signals at that intersection seem abnormally high... 

Come to think of it, I've seen that high mast mount in a few other examples you've posted. Must be a Washington thing...? NDOT's standard plans call for a side-mounted 3-section head to be 12 feet (on center) from the bottom of the mast (note the mast arm connects at 18.5 feet on center, so the signal is about 2/3 the way up the mast). And I'm fairly certain all the local agencies use NDOT's standard plans for their signal installations.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

Roadsguy

Seems PennDOT, who mostly (except in the Philly area) used full red circles alongside green and yellow arrows for dedicated turn signals, has been transitioning toward red arrows within the past three years or so. Most of the newest signal installations I see have them, for example here: https://goo.gl/maps/jHeReRx9Wmt
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traffic light guy

Quote from: Roadsguy on July 19, 2018, 10:22:08 AM
Seems PennDOT, who mostly (except in the Philly area) used full red circles alongside green and yellow arrows for dedicated turn signals, has been transitioning toward red arrows within the past three years or so. Most of the newest signal installations I see have them, for example here: https://goo.gl/maps/jHeReRx9Wmt

No, not true, some of Philly's suburbs use the red circle, only the city of Philadelphia uses the red arrow. However, since 2013, the suburbs have been using the arrow for newer installations.

roadman65

Quote from: jakeroot on July 18, 2018, 01:43:56 AM
Quote from: roadman65 on July 17, 2018, 07:10:55 PM
What is up with Ontario?  Not only does the province use two mast arms to do the job of one (as always is like NJ was with some and there with two arms on opposite side across from each other to mount both heads), but the backplates are all painted yellow.

Also they use 8 inch yellows and green lenses instead of all 12 like most states do.  Though the 12-8-8 is not bad as NJ used to have them around in many areas when I was growing up as well as Virginia they were very popular and some intersections in NYC use them as well.

Though the extra arm and all yellow backplates seem odd.

All yellow backplates are extremely common all across Canada. Black backplates are definitely in the minority. I think they're only found in the Prairies. No examples in BC that I know of.

I believe Ontario has switched over to all 300mm (12-inch) signals. BC seems to be the only province that still uses 200mm signals, using them for all (RYG) orbs, depending on location (overhead or pole, nearside or farside, etc). Red Deer, Alberta uses 200-200-200 right-side secondary signals at many intersections, but not sure if that's still normal.

Why double mast arms? No idea. Maybe wind load?




Quote from: MNHighwayMan on July 17, 2018, 07:23:55 PM
First, the yellow backplates, which are quite rare in Minnesota. (Maybe starting to become a thing? Not sure.)

Around here, they just popped up everywhere in the span of like two months. Only the city of Bellevue, WA still installs backplates without yellow tape.
Does Canada still use the fast flashing green for permissive left turns?  I remember that was common in Hamilton in 1984 and saw one in Niagara Falls in 1995 also.  So I assume it was a Canada (or a provincial thing).
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

NoGoodNamesAvailable

Quote from: roadman65 on July 20, 2018, 11:26:36 PM
Does Canada still use the fast flashing green for permissive left turns?  I remember that was common in Hamilton in 1984 and saw one in Niagara Falls in 1995 also.  So I assume it was a Canada (or a provincial thing).

Parts of Québec still use it. Montréal extensively, and I've seen it recently in Gatineau as well.

The other most noticeable difference from North American signing conventions is that Québec will usually post signs showing the obligatory movements at an intersection instead of the prohibited ones. (Green circle around a movement) means that a movement is obligatory. So instead of posting a (red cross through left turn) sign, Québec usually posts a (green circle around straight/right arrow) sign.

jakeroot

Quote from: roadman65 on July 20, 2018, 11:26:36 PM
Does Canada still use the fast flashing green for permissive left turns?  I remember that was common in Hamilton in 1984 and saw one in Niagara Falls in 1995 also.  So I assume it was a Canada (or a provincial thing).

BC and Alberta use flashing green protected arrows (BC only when the left turn has a permissive phase). Always a bi-modal 4-section setup. Except for a few 5-section "towers" in Alberta.

I believe Ontario uses solid green arrows for all circumstances; BC uses solid green arrows but only when the left turn doesn't have a permissive phase.

roadman65

Quote from: NoGoodNamesAvailable on July 20, 2018, 11:44:48 PM
Quote from: roadman65 on July 20, 2018, 11:26:36 PM
Does Canada still use the fast flashing green for permissive left turns?  I remember that was common in Hamilton in 1984 and saw one in Niagara Falls in 1995 also.  So I assume it was a Canada (or a provincial thing).

Parts of Québec still use it. Montréal extensively, and I've seen it recently in Gatineau as well.

The other most noticeable difference from North American signing conventions is that Québec will usually post signs showing the obligatory movements at an intersection instead of the prohibited ones. (Green circle around a movement) means that a movement is obligatory. So instead of posting a (red cross through left turn) sign, Québec usually posts a (green circle around straight/right arrow) sign.
Yeah I saw it in Ontario come to think of it.  Another thing that Canada does is leave out Railroad Crossing on the crossbuck but use an orange border and plain white X.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

cl94

A few regions/counties in Ontario still use the flashing green arrow, but not many. Most are solid. As far as 12-8-8 (30-20-20) signals, MTO no longer installs them, but some counties/regions continue to. Since several counties/regions/single-tier municipalities maintain every signal in their jurisdiction, we're still seeing new 12-8-8s, even at exit ramps and on provincially-maintained highways.

New Brunswick is flashing. That caught me by surprise when I was out there in 2016.
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jakeroot

Quote from: cl94 on July 21, 2018, 12:57:35 AM
New Brunswick is flashing. That caught me by surprise when I was out there in 2016.

I want to say that Ontario is the lone user of solid green arrows in bi-modal displays. Unless you've seen it in Quebec? I see (reading above) that the flashing green arrows are pretty common over there.

Pretty sure MB uses the flashing green arrow as well.

cl94

Quote from: jakeroot on July 21, 2018, 01:44:39 AM
Quote from: cl94 on July 21, 2018, 12:57:35 AM
New Brunswick is flashing. That caught me by surprise when I was out there in 2016.

I want to say that Ontario is the lone user of solid green arrows in bi-modal displays. Unless you've seen it in Quebec? I see (reading above) that the flashing green arrows are pretty common over there.

Pretty sure MB uses the flashing green arrow as well.

In Canada? I think so. I haven't seen one elsewhere.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

Travel Mapping (updated weekly)

jakeroot

Quote from: cl94 on July 21, 2018, 02:30:27 AM
Quote from: jakeroot on July 21, 2018, 01:44:39 AM
Quote from: cl94 on July 21, 2018, 12:57:35 AM
New Brunswick is flashing. That caught me by surprise when I was out there in 2016.

I want to say that Ontario is the lone user of solid green arrows in bi-modal displays. Unless you've seen it in Quebec? I see (reading above) that the flashing green arrows are pretty common over there.

Pretty sure MB uses the flashing green arrow as well.

In Canada? I think so. I haven't seen one elsewhere.

Yeah. I've always thought that, if the green and yellow arrows are going to share a single face, one should be differentiated by more than just color. A flashing green arrow, IMO, is brilliant. Surprised that Ontario doesn't utilise it (anymore?). I would love to see the option here in the US. Though, with the advent of the FYA, I doubt any additional research into traditional yield-on-green signals is warranted.

paulthemapguy

Sideways signals done the right way!
The indications of a horizontal 5-section head in Wisconsin or Illinois, in order of appearance:

From a red light...


IL-CWL-01-1 by Paul Drives, on Flickr

The leading left turn arrow appears...


IL-CWL-01-2 by Paul Drives, on Flickr

The yellow arrow appears to signal the end of the left turning phase...


IL-CWL-01-3 by Paul Drives, on Flickr

And the light turns green, in this case slightly before the oncoming traffic gets their green light.


IL-CWL-01-4 by Paul Drives, on Flickr

This is when there's a leading left turn (99.5% of intersections in Illinois do this), and the sections are ordered in the correct sequence from left to right.  If the green ball is still in the center, you're doing it wrong.
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steviep24

Quote from: paulthemapguy on July 21, 2018, 09:43:49 AM
Sideways signals done the right way!
The indications of a horizontal 5-section head in Wisconsin or Illinois, in order of appearance:

From a red light...


IL-CWL-01-1 by Paul Drives, on Flickr

The leading left turn arrow appears...


IL-CWL-01-2 by Paul Drives, on Flickr

The yellow arrow appears to signal the end of the left turning phase...


IL-CWL-01-3 by Paul Drives, on Flickr

And the light turns green, in this case slightly before the oncoming traffic gets their green light.


IL-CWL-01-4 by Paul Drives, on Flickr

This is when there's a leading left turn (99.5% of intersections in Illinois do this), and the sections are ordered in the correct sequence from left to right.  If the green ball is still in the center, you're doing it wrong.
NY does their horizontal signals this way as well and I've never seen a five section horizontal signal with green ball in the middle.

Big John

Quote from: steviep24 on July 21, 2018, 12:44:41 PM
]NY does their horizontal signals this way as well and I've never seen a five section horizontal signal with green ball in the middle.
A green ball in the middle is appropriate when right turn arrows are used.  R-Y-G-YA-GA, though this arrangement is used a lot less frequently.

jakeroot

Quote from: Big John on July 21, 2018, 01:54:48 PM
Quote from: steviep24 on July 21, 2018, 12:44:41 PM
]NY does their horizontal signals this way as well and I've never seen a five section horizontal signal with green ball in the middle.

A green ball in the middle is appropriate when right turn arrows are used. R-Y-G-YA-GA, though this arrangement is used a lot less frequently.

It's normal in most western states to have the R-Y-G-YA-GA (5-section tower) setup on the right mast for right turn overlap phasing (right turn filters). WA uses many 4-section (bi-modal) signals for the job, but CA, AZ, NV, NM, CO, IL, WI, MN, IA, NE, and SD all use 5-section towers on the right with the green ball in the middle (as you'd expect) for this purpose.

paulthemapguy

I should note, for those who aren't aware:  The reason I posted these signals is because horizontal signal heads are NEVER used in Illinois, except in extremely rare circumstances.  So for Illinoisans, this is a really special case.
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RestrictOnTheHanger

Quote from: steviep24 on July 21, 2018, 12:44:41 PM
NY does their horizontal signals this way as well and I've never seen a five section horizontal signal with green ball in the middle.

Here is an example of a 5 light horizontal signal in NY.

Although this was installed relatively recently as a replacement to an older signal, supposedly it is going away as a reconfiguration of the associated parkway exit

NY-231

https://goo.gl/maps/zHLzMa2Dowp

SignBridge

#1872
I hadn't realized 'til now that the MUTCD spec for horizontal signals is different for heads with left vs. right turn arrows. With left-turn arrows, the green ball is at the right end of the head. But with right-turn arrows it's in the middle. Anyone know why the difference? You'd think it would be the same for both or at least I thought so....

Also that Illinois signal pictured above is probably next to an airport, judging from the low height of the street lamps. Maybe that's the reason for the rare horizontal heads too, though you wouldn't think that would make any difference to low-flying planes. They don't fly that low!

NoGoodNamesAvailable

Quote from: jakeroot on July 21, 2018, 01:44:39 AM
Quote from: cl94 on July 21, 2018, 12:57:35 AM
New Brunswick is flashing. That caught me by surprise when I was out there in 2016.

I want to say that Ontario is the lone user of solid green arrows in bi-modal displays. Unless you've seen it in Quebec? I see (reading above) that the flashing green arrows are pretty common over there.

Pretty sure MB uses the flashing green arrow as well.

I should have elaborated. Older installations in QC actually use a flashing green ball indication on every signal to indicate a protected left. I don't believe installations with arrows generally flash in the province.

Big John

Quote from: SignBridge on July 21, 2018, 09:37:22 PM
I hadn't realized 'til now that the MUTCD spec for horizontal signals is different for heads with left vs. right turn arrows. With left-turn arrows, the green ball is at the right end of the head. But with right-turn arrows it's in the middle. Anyone know why the difference? You'd think it would be the same for both or at least I thought so....
I believe that it is because the left-turning traffic is to the left of through traffic, that the left arrows are to the left of the green ball, anf the right-turning traffic is to the right of through traffic.  Similar the the placement of arrows on a doghouse signal.



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