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Author Topic: OTM Book 12 "Standard/Highway" Signals  (Read 9026 times)

MisterSG1

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #25 on: July 25, 2016, 12:50:07 PM »

What would be the advantage of using an FYA in this situation over green arrows? Is it to give pedestrians the opportunity to cross?

The question is, how else can you do this safely. So let's again use the previous example I mentioned. A 4 way regular intersection where there are no turning restrictions. For the record, we shall decide to give NB an "extended green" or a "lagging left" to clear left turning traffic after the end of the through phase. (An "advanced green" or "leading left" does the opposite, it clears left turning traffic before the main through phase)

Now for the left turning traffic facing NB, we could use Signal Type 2 in this situation currently. This is a fully protected left turn, and with this comes the obvious disadvantage of potentially facing a total lack of oncoming traffic and not being allowed to turn. So using Signal Type 2, the NB-SB phase would run like this, if NB gets an extended green:

NB Left Signal    NB Main Signal    SB Main Signal
Red BallRed BallRed Ball
Red BallGreen BallGreen Ball
Red BallGreen BallYellow Ball
Red BallGreen BallRed Ball
Green ArrowGreen BallRed Ball
Yellow BallYellow BallRed Ball
Red BallRed BallRed Ball

As you can see, a lagging left can be created here. But as this a fully protected left turn signal, traffic won't be allowed to turn left AT ALL until the green arrow appears, which won't happen until the traffic facing SB gets a red (and some time for red clearance to protect left turners against red light runners).

So watch what happens if we try to use singal Type 9 or 10, in other words the protected-permissive signal, in this example, what appears in the table for "NB Left Signal" will be what appears in the arrow signal head at the bottom:

NB Left Signal    NB Main Signal    SB Main Signal
Red BallRed Ball
Green BallGreen Ball
Green BallYellow Ball YELLOW TRAP!!
Green BallRed Ball
Green ArrowGreen BallRed Ball
Yellow ArrowYellow BallRed Ball
Red BallRed Ball

As we can see, as NB has the extended green, traffic turning left facing SB will get an early yellow while NB still faces a green. Causing what we all know as the yellow trap. A driver stuck in the intersection waiting to make a turn will not know the status of the oncoming through light, and thus it could be a good 15 seconds or more before the oncoming signal gets a yellow. There is also the more obvious issue of drivers not being aware that one side faces an extended green and thus a driver turning left assumes the car coming towards him is stopping when it isn't and this could lead to a jarring collision.

When we introduce FYA, we can do this safely, and here is how, the real disadvantage is that SB, although it gets no protected movements in this case will have to get a FYA signal as well.

NB Left Signal    NB Main Signal    SB Main Signal    SB Left Signal
Red ArrowRed BallRed BallRed Arrow
FLASHING Yellow ArrowGreen BallGreen BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallYellow BallSOLID Yellow Arrow
FLASHING Yellow ArrowGreen BallRed BallRed Arrow
Green ArrowGreen BallRed BallRed Arrow
SOLID Yellow ArrowYellow BallRed BallRed Arrow
Red ArrowRed BallRed BallRed Arrow

And there we have it. In this case, NB turns can be made through the entire sequence as this is now a PPLT situation. SB traffic turning left WILL NOT get caught in a yellow trap now. Of course you can see the ambiguity I discussed on my other thread at play here, the solid yellow arrow, before all solid yellow arrows were protected, now in this case, SB's solid yellow arrow is actually a non protected yellow. That is the only real issue I have with the FYA signal myself.

EDIT!!

There is a yellow trap I missed in the first example involving SB traffic. It's getting late now and I'll correct it sometime tomorrow.

I'll ignore the first table for now since it still appears to have a yellow trap ;)

For the FYA, do drivers have to stay behind the stop line, or can they inch into the intersection like you would for a regular green light? I'm guessing you have to stay back, because otherwise it would appear to be another yellow trap.

Ok, in the first example, the only way I could eliminate the trap there would be to introduce a fully protected left turn for traffic facing the SB light. This fully protected signal could run concurrently with the NB left turn signal (in essence creating a simultaneous lagging turn) or a lead-lag protected turn situation, here SB gets their left turn at the beginning of the sequence, and NB gets their left turn at the end.

The first example is not really important for the issue at hand.

The yellow trap is a situation where suppose you are turning left, and you are in the intersection, you wait for a gap to make the turn, your light turns yellow, so you usually assume that oncoming traffic will come to a stop, but since oncoming traffic faces a green, they won't stop.

When FYA is added, the traffic heading SB that wants to turn left, who are yellow trapped normally won't be because there is now a dedicated signal for a left PERMISSIVE turn. Indeed, SB in our intersection never gets a protected phase for left turns.

When the solid yellow appears for SB (in this situation) this will mean that the oncoming traffic will face a yellow as well, and thus a driver won't be yellow trapped here.

Inching out into the intersection, that behavior will not change whatsoever, you would treat a FYA just as you would treat a green in a permissive turn situation, you wait for a gap and then move it.
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MisterSG1

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #26 on: July 25, 2016, 02:25:33 PM »

I just realized, I made a BIG MISTAKE, in my example of the FYA....the yellow trap is still there and I didn't alter the sequence to reflect that, this is what caused your confusion I'm sure

This is what I originally posted for the FYA phasing using an extended green for NB:

NB Left Signal    NB Main Signal    SB Main Signal    SB Left Signal
Red ArrowRed BallRed BallRed Arrow
FLASHING Yellow ArrowGreen BallGreen BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallYellow BallSOLID Yellow Arrow
FLASHING Yellow ArrowGreen BallRed BallRed Arrow
Green ArrowGreen BallRed BallRed Arrow
SOLID Yellow ArrowYellow BallRed BallRed Arrow
Red ArrowRed BallRed BallRed Arrow

Yes, I realized, SB Left will still be yellow trapped in this situation, this is how the sequence would work with FYA:

NB Left Signal    NB Main Signal    SB Main Signal    SB Left Signal
Red ArrowRed BallRed BallRed Arrow
FLASHING Yellow ArrowGreen BallGreen BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallYellow BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallRed BallFLASHING Yellow Arrow
Green ArrowGreen BallRed BallFLASHING Yellow Arrow
SOLID Yellow ArrowYellow BallRed BallSOLID Yellow Arrow
Red ArrowRed BallRed BallRed Arrow

Now the yellow trap has been eliminated 100%. That was an error I made before with cut and paste and not thinking, but this is the correct sequencing now.
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7/8

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #27 on: July 25, 2016, 03:17:25 PM »

I just realized, I made a BIG MISTAKE, in my example of the FYA....the yellow trap is still there and I didn't alter the sequence to reflect that, this is what caused your confusion I'm sure

This is what I originally posted for the FYA phasing using an extended green for NB:

NB Left Signal    NB Main Signal    SB Main Signal    SB Left Signal
Red ArrowRed BallRed BallRed Arrow
FLASHING Yellow ArrowGreen BallGreen BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallYellow BallSOLID Yellow Arrow
FLASHING Yellow ArrowGreen BallRed BallRed Arrow
Green ArrowGreen BallRed BallRed Arrow
SOLID Yellow ArrowYellow BallRed BallRed Arrow
Red ArrowRed BallRed BallRed Arrow

Yes, I realized, SB Left will still be yellow trapped in this situation, this is how the sequence would work with FYA:

NB Left Signal    NB Main Signal    SB Main Signal    SB Left Signal
Red ArrowRed BallRed BallRed Arrow
FLASHING Yellow ArrowGreen BallGreen BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallYellow BallFLASHING Yellow Arrow
FLASHING Yellow ArrowGreen BallRed BallFLASHING Yellow Arrow
Green ArrowGreen BallRed BallFLASHING Yellow Arrow
SOLID Yellow ArrowYellow BallRed BallSOLID Yellow Arrow
Red ArrowRed BallRed BallRed Arrow

Now the yellow trap has been eliminated 100%. That was an error I made before with cut and paste and not thinking, but this is the correct sequencing now.

Awesome, yes that solves my confusion :).

Inching out into the intersection, that behavior will not change whatsoever, you would treat a FYA just as you would treat a green in a permissive turn situation, you wait for a gap and then move it.

I can see from your new table that this makes sense now. I should reread your FYA thread now that I understand this better. Thanks MisterSG1! :)

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #28 on: July 30, 2016, 09:16:01 AM »

If we can go back to the original question at hand in this thread, there's a 20/20/20 signal at Derry and Hull in Mississauga. (incidentally I mentioned this intersection on the 'split phase' thread I made)

https://goo.gl/maps/2x98cwFkTRt
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #29 on: August 02, 2016, 12:13:30 PM »

If we can go back to the original question at hand in this thread, there's a 20/20/20 signal at Derry and Hull in Mississauga. (incidentally I mentioned this intersection on the 'split phase' thread I made)

https://goo.gl/maps/2x98cwFkTRt

^ Good find :)

I was in Meaford yesterday for Civic Holiday and I saw a 20/20/20 signal on Hwy 26 at Trowbridge St (the signal on the right in the GSV below). Also, on GSV, I see there's another one on the opposite side of the intersection! :)


I wish I brought my camera, because the signal on the left in the above photo had no backboard, which was cool. According to page 86 of book 12:

Quote
Backboards are recommended for all primary heads and are preferred on all heads except secondary heads used at very low posted speeds of 50 km/h or less.

So I guess this is allowed, but I'm guessing that it's only temporary and that a backboard will be reinstalled soon.
« Last Edit: August 02, 2016, 12:51:33 PM by 7/8 »
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #30 on: September 01, 2016, 09:59:14 AM »

I found another 20/20/20 signal, this time in Pembroke, ON at McKay St and Nelson St.

Unfortunately I didn't get a photo, but here's the location in Google Maps: https://goo.gl/maps/J2JdufxrXBm

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #31 on: September 01, 2016, 11:23:44 PM »

I found yet another 20/20/20 signal, this time in Ottawa at Vanier Pkwy and Donald St. It also doesn't have a backplate. Here's a photo I took today:



I saw a similar one at Wellington St and Metcalfe St, though I don't have a photo.

--------

To change the subject to something more interesting, I find it interesting how Ottawa uses straight green arrows when right turns are channelized. Just one of many examples is heading EB on McArthur St at Vanier Pkwy. But what I find particularly interesting is how the three signals heads are 30/20/30. The OTM Book 12 doesn't show this on the list of signals, but it seems very common place in Ottawa. Instead, the OTM shows Types 1, 2, and 3 with the yellow lights being 30 instead of 20cm.
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cl94

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #32 on: September 01, 2016, 11:51:08 PM »

Now that's an oddity. Even here in the Northeast, it's becoming less and less common to see signals without backplates in rural/suburban areas. I didn't think Canada had any without backplates.
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7/8

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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #33 on: September 01, 2016, 11:55:37 PM »

Now that's an oddity. Even here in the Northeast, it's becoming less and less common to see signals without backplates in rural/suburban areas. I didn't think Canada had any without backplates.

I'm surprised I managed to find 2 in half-a-day in Ottawa. I'll be here for another 2 full days, so I'll have to be on the look out for more!
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #34 on: September 02, 2016, 10:21:04 AM »

Look at Huron Church Road in Windsor... signals without back plates are not exactly a rarity.
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #35 on: September 04, 2016, 08:50:58 PM »

Look at Huron Church Road in Windsor... signals without back plates are not exactly a rarity.

I guess your right. I haven't seen a single one in Waterloo Region*, but Ottawa had them all over the place (at first I was keeping track, but then it got to the point where I realized there's no point). One thing I found interesting is that the 20/20/20 no backplate signals in Ottawa were always on the left side of the intersection, with "regular" signals in the middle and/or right.

UPDATE Sept. 7th: I managed to find one today at King St and Fountain St in Cambridge (photo here).

To change the subject to something more interesting, I find it interesting how Ottawa uses straight green arrows when right turns are channelized. Just one of many examples is heading EB on McArthur St at Vanier Pkwy. But what I find particularly interesting is how the three signals heads are 30/20/30. The OTM Book 12 doesn't show this on the list of signals, but it seems very common place in Ottawa. Instead, the OTM shows Types 1, 2, and 3 with the yellow lights being 30 instead of 20cm.

I ended up taking a photo of one of these signals:



I also want to make it clear that they're used in many situations, not just channelized right turns. In fact, I get the impression that Ottawa tries to use these signals as much as possible.
« Last Edit: September 07, 2016, 04:54:56 PM by 7/8 »
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #36 on: September 04, 2016, 09:27:13 PM »

And if you want to see something interesting with backplates.....go look at the intersections in downtown Richmond Hill, it almost feels as if you are in SoCal......
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #37 on: September 05, 2016, 04:32:33 PM »

And if you want to see something interesting with backplates.....go look at the intersections in downtown Richmond Hill, it almost feels as if you are in SoCal......

I almost want to go to downtown Richmond Hill just to see the black signals :)

----------

The signals at Macdonell St and Arthur St in Guelph, ON are interesting. The green light appears to be farther outward from the backplate than the yellow and red lights. From straight on, the green light almost looks off-centre (see posted GSV link)! Here are two photos taken from the side:




Does anyone have any ideas why this signal is like this?
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Re: OTM Book 12 "Standard/Highway" Signals
« Reply #38 on: September 05, 2016, 04:56:22 PM »

The green is likely a 3M PV converter. Although they never made 8" heads, they did sell 8" converters.
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