Traffic signal

[roadfro]

After watching this video about Connecticut traffic lights, I see that Connecticut is still installing new 8-inch (203 mm) signal heads...

Federal Rd, Old New Milford Rd and Junction Rd in Brookfield CT

The old intersection used to use 12-inch (305 mm) heads for this leg... is it possible that section 4D.07.02 and 03 in the 2009 MUTCD permit this configuration, as well as the proximity of the two intersections?

Standard:

02 Except as provided in Paragraph 3 below, 12-inch signal indications shall be used for all signal sections in all new signal faces.

Option:
03 Eight-inch circular signal indications may be used in new signal faces only for:

B. The circular indications in signal faces controlling the approach to the downstream location where two adjacent signalized locations are close to each other and it is not practical because of factors such as high approach speeds, horizontal or vertical curves, or other geometric factors to install visibility-limited signal faces for the downstream approach;

C. The circular indications in a signal face that is located less than 120 feet from the stop line on a roadway with a posted or statutory speed limit of 30 mph or less.

Yeah, the 8" signals are fine here. Personally, I don't like them when other options could be deployed.

What confuses me more about this installation (and the adjacent intersection), is that there were perfectly fine signal installations with fixed mast arm mountings and then they were replaced with span wire installations. That doesn't make sense to me...

[jeffandnicole]

I've noticed it too, that Connecticut is not one of the smarter states when it comes to traffic light installations. Massachusetts notably does far better at least in more recent installations.

In what way?  In regards to the 8 inch lights mentioned above, they were installed in full compliance with the MUTCD.  If anything, it's the states which install 12" lights too close together that are more of an issue!

[Big John]

^^ The minimum distance is 8 feet apart regardless of signal size.

[kj3400]

Lord knows this isn't 8 feet...

[jeffandnicole]

^^ The minimum distance is 8 feet apart regardless of signal size.

In those examples? They all appear to be at least 8 feet apart.

Kj's wxample...yeah...um...No!!!

[silveradoman298]

I miss these old 12in/8in combination traffic lights manufactured by Eagle and Marbelite.

https://www.google.com/maps/@42.5600244,-83.0098989,3a,38.4y,352.39h,89.3t/data=!3m6!1e1!3m4!1sDsOz3gtC1d81qMr_6WLs5w!2e0!7i13312!8i6656

https://www.google.com/maps/@42.5601929,-83.0101225,3a,50.9y,91.15h,93.5t/data=!3m6!1e1!3m4!1s3gIdvduJVkSGQC80K_UmZQ!2e0!7i13312!8i6656

[SignBridge]

Just a technical point-of-information, the rule requiring the two thru signals to be eight feet apart is measured from center-of-lens to center-of-lens, in case anyone wondered.

And that rule only applies to the two thru circular-green signals. Not to any supplemental heads or turn-signal heads. 

[silveradoman298]

Vernier At I-94 by Silveradoman298, on Flickr

Vernier At I-94 (2) by Silveradoman298, on Flickr

Somehow this interesting 3M arrangement has stood the test of time. Another Michigan rarity.

[jakeroot]

Does anyone have any idea what's going on at this off-ramp signal from northbound I-25 in Castle Rock, CO?

https://goo.gl/maps/HNUHWDzHnWeQp5p46

[plain]

Does anyone have any idea what's going on at this off-ramp signal from northbound I-25 in Castle Rock, CO?

https://goo.gl/maps/HNUHWDzHnWeQp5p46

Very strange signals. Seems to me neither 4-section needs red arrows (especially in conjunction with red orbs on the same signal!!). A red orb, yellow orb, and left & right green arrows would've been fine.

Crazy how the red arrows on the mast-arm mounted and side mounted signals clash with each other there..

[fwydriver405]

One late night driving around Bangor, I noticed some very interesting and odd flash mode sequencing:

1. The pedestrian signals are not supposed to flash at all when in flash mode, correct? If illegal, what section of the MUTCD does that violate?

2. At 0:35 in the video, notice how there are three yellow balls flashing, but the signal to the furthest right is flashing red ball. Does that require a RIGHT TURN SIGNAL sign, or at least have that signal flash yellow like the other lights as well? The signal to the furthest right acts as a right turn overlap.

3. The same could be said at 0:15 in, but the left and rightmost signal heads in normal operation hold turning traffic with red balls to allow peds to cross... very strange seeing red balls for the turning movement* and yellow balls for the thru movements...

4. Are the turning movements and thru signals supposed to flash in unison or alternate?

*Yes, I do know that some states like Pennsylvania use red balls for protected only left-turn signals. So in that case, for signals that flash overnight, that would not be an unusual thing to see. However, in Maine, NH and MA, red left-turn arrows are common for protected only phasing (and FYA signals as well), and red balls for an exclusive left (right) turn signals are rare around here...

[Big John]

1. The pedestrian signals are not supposed to flash at all when in flash mode, correct? If illegal, what section of the MUTCD does that violate?

Section 4E.06 Pedestrian Intervals and Signal Phases

Standard:
01 At intersections equipped with pedestrian signal heads, the pedestrian signal indications shall be displayed except when the vehicular traffic control signal is being operated in the flashing mode. At those times, the pedestrian signal indications shall not be displayed.

[roadfro]

2. At 0:35 in the video, notice how there are three yellow balls flashing, but the signal to the furthest right is flashing red ball. Does that require a RIGHT TURN SIGNAL sign, or at least have that signal flash yellow like the other lights as well? The signal to the furthest right acts as a right turn overlap.

3. The same could be said at 0:15 in, but the left and rightmost signal heads in normal operation hold turning traffic with red balls to allow peds to cross... very strange seeing red balls for the turning movement* and yellow balls for the thru movements...

4. Are the turning movements and thru signals supposed to flash in unison or alternate?

For 2 & 3: It seems like a "Right turn signal" or "Left turn signal" sign is needed for flash mode and regular operation as well if there's a circular red indication controlling the turning movement there. If a red arrow had been used, then these would not need such a sign. 2009 MUTCD 4D.30p08 standard says that all signals flashed on an approach must flash the same color, except for turn signal faces which may flash red arrows when adjacent through faces flash circular yellow.

4: The MUTCD does not specify that all signal heads on an approach flash in unison or alternate. I've actually wondered about this previously when encountering an all-way red flash–most signals around the Las Vegas, NV area flash all signal heads on an approach simultaneously, whereas many signals around Reno, NV area have the left turn signals and through signals flash red alternately.

[SignBridge]

Re: signals flashing in unison or alternately in the same direction. I've seen both configurations in the Northeast. 

[fwydriver405]

Anyone have a clue when and why the traffic signals near the SB O'Neil Tunnel entrance (and Southeast Expressway, with the lane control signals) were removed?

My guess as to the "why" would be because that's not a valid use of standard RYG traffic signals, which are meant to convey stop/go and not lane control information. For those, they need to use the ×/down arrow signals.

I think I may have found the answer to the traffic signals around the Central Artery / I-90 tunnels. After stumbling across this document ("RAMP METERING STATUS IN NORTH AMERICA. 1995 UPDATE") by the FHWA, three mainline meters were supposed to be activated as part of the Central Artery Project, all at entrances to tunnels. Not sure where those meters were supposed to be placed, but according to the document:

As part of the Central Artery project, 3 locations will have mainline metering. All three locations are at portals to control flow through tunnels. Ramp metering is also being considered at 12 locations. Further studies will be done to insure the feasibility of the meters. Earliest activation would be near the year 2000.

Were the traffic signals at the entrances to the Central Artery tunnels supposed to be ramp meters at some point, before being abandoned and eventually removed? I wonder if MA will get ramp meters in the future...

[silveradoman298]

Here's a few odd signal combinations I came across in Detroit, MI.

Greenfield at I-94 Exit (2019) by Silveradoman298, on Flickr

Greenfield at I-94 Exit (2011) by Silveradoman298, on Flickr

John Kronk at Lonyo (2009)(2)(3M) by Silveradoman298, on Flickr

John Kronk at Lonyo (2019)(3)(3M) by Silveradoman298, on Flickr

[jakeroot]

Here's a few odd signal combinations I came across in Detroit, MI.

Greenfield at I-94 Exit (2019) by Silveradoman298, on Flickr

Greenfield at I-94 Exit (2011) by Silveradoman298, on Flickr

Nearside-left placement. Bit unusual! I like it.

Must say, all things considered, Michigan has surprisingly good signal placement for as old fashioned as things appear.

[ErmineNotyours]

Here's a few odd signal combinations I came across in Detroit, MI.

John Kronk at Lonyo (2009)(2)(3M) by Silveradoman298, on Flickr

John Kronk at Lonyo (2019)(3)(3M) by Silveradoman298, on Flickr

Ugh.  3M louvered on a span wire?  Do they not get the concept?  Maybe there's no wind there.

[thenetwork]

Here's a few odd signal combinations I came across in Detroit, MI.

John Kronk at Lonyo (2009)(2)(3M) by Silveradoman298, on Flickr

John Kronk at Lonyo (2019)(3)(3M) by Silveradoman298, on Flickr

Ugh.  3M louvered on a span wire?  Do they not get the concept?  Maybe there's no wind there.

Looks like its a set of signals next to a railroad crossing.  Likely the 3Ms may operate independently of the signals before the railroad crossing, and are really only for the traffic between the railroad and cross-street.

[jakeroot]

Looks like its a set of signals next to a railroad crossing.  Likely the 3Ms may operate independently of the signals before the railroad crossing, and are really only for the traffic between the railroad and cross-street.

It's not that 3Ms aren't required, but that they're mounted on span wire. All things considered, that's a rare combo, least from what I've seen.

[CJResotko]

Here's an interesting setup in Farmington Hills, MI, at the intersection of Grand River Ave. - Halsted Rd./Freedom Rd:
https://www.google.com/maps/@42.4688266,-83.4156965,3a,31.8y,171.83h,98.66t/data=!3m7!1e1!3m5!1slPzaPj3Aq9LxVYn92TIInQ!2e0!5s20161001T000000!7i13312!8i6656

At the southbound approach, there are two 4-section signals. The bottom two lights on them are green arrows. The bottom one turns on when EB Grand River Ave has a protected left turn, and the other one turns on when Halsted Road has the green light.

The one at exit 13 at M-5 is very similar: https://www.google.com/maps/@42.4680325,-83.418529,3a,75y,325.68h,100.27t/data=!3m7!1e1!3m5!1sHdSueltmkgd-QcAPC-g2Cw!2e0!5s20181101T000000!7i16384!8i8192

[jakeroot]

Here's an interesting setup in Farmington Hills, MI, at the intersection of Grand River Ave. - Halsted Rd./Freedom Rd:
https://www.google.com/maps/@42.4688266,-83.4156965,3a,31.8y,171.83h,98.66t/data=!3m7!1e1!3m5!1slPzaPj3Aq9LxVYn92TIInQ!2e0!5s20161001T000000!7i13312!8i6656

At the southbound approach, there a two 4-section signals. The bottom two lights on them are green arrows. The bottom one turns on when EB Grand River Ave has a protected left turn, and the other one turns on when Halsted Road has the green light.

So there's two green arrows? "Interesting" is an understatement.

[Big John]

^^ Looking at the road, were straight movements once allowed? meaning where the upper arrow is now then controlled the through movement and when that was disallowed all they did was to replace the lens with a green arrow.

[UnumProvident101]

This intersection in Chattanooga, TN has traffic lights like these and there is 4 of them

and so does this other one

[hotdogPi]

This intersection in Chattanooga, TN has traffic lights like these and there is 4 of them

and so does this other one

What am I supposed to be looking for here?