I would like to know, does anyone know what cities use bimodal green arrows/yellow arrows (not FYA)?
I noticed there are lots of them in Scottsdale. I wonder if it may have anything to do with the fact that Scottsdale mostly uses lagging left turn phasing. Gilbert and Goodyear also mostly use lagging left turn phasing but do not use bimodal heads. For signals that allow permissive left turns, Gilbert mostly used 5-section towers (although there are a few doghouses), while Goodyear mostly uses "crooked" doghouses (Goodyear uses modular poles, which have a separate two-head signal with arrows next to a regular three head signal with circular indications).
Cities shouldn't use them, for what it's worth, but in my area:
- mostly in place of doghouses for protected rights (most cases)
- In and around Tacoma, Washington (particularly downtown), there's quite a few bimodal arrows for left turns
- Milton/Edgewood, Washington (small town south of Seattle) did a recent street upgrade where most/all of the signals are of the bimodal type
- Tukwila, Washington (larger city south of Seattle) has quite a few along major arterials
- I don't see very many new installations given the recent preference for the FYA
Given my experience with Canada, I'd love to try an experiment with the bimodal arrows whereby the green arrow flashed, indicating a protected turn, then stopped flashing on an amber arrow, then disappeared (this should help distinguish between the two for color-blind individuals).
Quote from: jakeroot on March 13, 2015, 11:17:46 PM
Given my experience with Canada, I'd love to try an experiment with the bimodal arrows whereby the green arrow flashed, indicating a protected turn, then stopped flashing on an amber arrow, then disappeared (this should help distinguish between the two for color-blind individuals).
Of course, that may cause confusion with some Mexican drivers, as a flashing green indication in Mexico indicates that the green phase is about to end.
Quote from: Pink Jazz on March 13, 2015, 11:37:17 PM
Quote from: jakeroot on March 13, 2015, 11:17:46 PM
Given my experience with Canada, I'd love to try an experiment with the bimodal arrows whereby the green arrow flashed, indicating a protected turn, then stopped flashing on an amber arrow, then disappeared (this should help distinguish between the two for color-blind individuals).
Of course, that may cause confusion with some Mexican drivers, as a flashing green indication in Mexico indicates that the green phase is about to end.
Well, I guess that's a geographical thing, since I've never actually seen a car with Mexico plates outside of San Diego. I'm more used to seeing Canadian plates.
Quote from: jakeroot on March 13, 2015, 11:49:10 PM
Well, I guess that's a geographical thing, since I've never actually seen a car with Mexico plates outside of San Diego. I'm more used to seeing Canadian plates.
I have seen several Mexican plates in Arizona and New Mexico. However, both are border states.
Quote from: Pink Jazz on March 13, 2015, 10:43:23 PM
I would like to know, does anyone know what cities use bimodal green arrows/yellow arrows (not FYA)?
Rockford, Illinois still has a ton of them.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi837.photobucket.com%2Falbums%2Fzz298%2Fmidamcrossrds%2F100_3218_zps51b76e57.jpg&hash=2d5ca169920671cdc56e69d3197e75ca23b7c349) (http://s837.photobucket.com/user/midamcrossrds/media/100_3218_zps51b76e57.jpg.html)
Some IDOT districts used to use them as recently as a few years ago, but many have been phased out recently.
Bi-modal signals are unheard of in New York City and will likely not appear in the future; however, a lot of towns and cities here in New Jersey use them. Doghouses (traditional setup) are in use, too, but they are not common.
Helena, MT has several, as does Oro Valley, AZ.
They're fairly common in Johnson County, Kansas (suburban KC), also in Enid, Oklahoma.
Quote from: M3019C LPS20 on March 14, 2015, 01:14:33 AM
...however, a lot of towns and cities here in New Jersey use them. Doghouses (traditional setup) are in use, too, but they are not common.
Technically, almost all of NJ uses bimodals, and in NJ the bimodal G/Y is the traditional setup, not the doghouse. A few counties may use doghouses as their primary install, but that's against the norm. There's a rare NJDOT doghouse or tower as well. It's not really up to the towns, as it's installed by NJDOT or the county, regardless of the town.
Dublin, Ohio uses them, mostly for traffic turning right.
They're not MUTCD compliant - for sure
Quote from: SSOWorld on March 14, 2015, 11:43:12 PM
They're not MUTCD compliant - for sure
They are compliant.
The 2009 MUTCD refers to them in sections 4D.09 & 4D.10, Standard 04. The text from 4D.09:
Quote
If a dual-arrow signal section (capable of alternating between the display of a GREEN ARROW and a YELLOW ARROW signal indication) is used in a vertically-arranged signal face, the dual-arrow signal section shall occupy the same position relative to the other sections as the signal section that displays the GREEN ARROW signal indication in a vertically-arranged signal face would occupy.
Haven't seen any of these in Huntsville or anywhere in Alabama for that matter.
Quote from: jakeroot on March 13, 2015, 11:17:46 PM
Given my experience with Canada, I'd love to try an experiment with the bimodal arrows whereby the green arrow flashed, indicating a protected turn, then stopped flashing on an amber arrow, then disappeared (this should help distinguish between the two for color-blind individuals).
I would rather see flashing green arrows used for situations where a turning movement has the right of way, but other vehicles that could conflict with said turn do not have a red ball or arrow. Best example would be a right turn movement that does not have a parallel crosswalk, but the opposing left turn has a FYA. The way the MUTCD currently seems to read is that this right turn should use a FYA if it is not using a green ball in a shared signal face. Using a FYA for the right turn in this case does not see appropriate, since the right turn has nothing to yield to.
Quote from: Brandon on March 14, 2015, 12:05:47 AM
Some IDOT districts used to use them as recently as a few years ago, but many have been phased out recently.
They are forbidden in the Chicago District.
I think colorblind people can see yellow. So even if they couldn't see the exact color of the green arrow, they would know when it is yellow.
Quote from: jeffandnicole on March 15, 2015, 02:26:12 PM
I think colorblind people can see yellow. So even if they couldn't see the exact color of the green arrow, they would know when it is yellow.
Many but not all; there are many kinds of color-blindness. There are those who see the world only in shades of grey.
Maybe I'm being pre-historic, but what's the big deal if they can't tell the difference between green and yellow? Most people blow through yellow anyways.
Quote from: jakeroot on March 15, 2015, 03:19:37 PM
Maybe I'm being pre-historic, but what's the big deal if they can't tell the difference between green and yellow? Most people blow through yellow anyways.
I was thinking the same thing - many years ago there was only a green arrow, then it turned dark - no yellow interval.
But then again, we didn't need a FYA because people understood to yield on green before making a left turn...
Quote from: jeffandnicole on March 15, 2015, 03:21:31 PM
Quote from: jakeroot on March 15, 2015, 03:19:37 PM
Maybe I'm being pre-historic, but what's the big deal if they can't tell the difference between green and yellow? Most people blow through yellow anyways.
I was thinking the same thing - many years ago there was only a green arrow, then it turned dark - no yellow interval.
Perhaps it would help solidify the fact that if a doghouse signal is green, and the arrow goes from green to yellow to blank, yellow doesn't mean slam on the brakes and wait behind the stop line ... it means keep going because you still have a green light and they haven't been able to move off yet. At least that's how I think about it. If you just did away with yellow altogether, there wouldn't be a "I see yellow therefore I stop" group of people ruining things for everyone.
Quote from: jeffandnicole on March 15, 2015, 03:21:31 PM
But then again, we didn't need a FYA because people understood to yield on green before making a left turn...
FYAs do have advantages over traditonal 5-section housings, but I see your point.
Quote from: Revive 755 on March 15, 2015, 01:44:42 PM
Quote from: jakeroot on March 13, 2015, 11:17:46 PM
Given my experience with Canada, I'd love to try an experiment with the bimodal arrows whereby the green arrow flashed, indicating a protected turn, then stopped flashing on an amber arrow, then disappeared (this should help distinguish between the two for color-blind individuals).
I would rather see flashing green arrows used for situations where a turning movement has the right of way, but other vehicles that could conflict with said turn do not have a red ball or arrow. Best example would be a right turn movement that does not have a parallel crosswalk, but the opposing left turn has a FYA. The way the MUTCD currently seems to read is that this right turn should use a FYA if it is not using a green ball in a shared signal face. Using a FYA for the right turn in this case does not see appropriate, since the right turn has nothing to yield to.
[/quote]
For the instance of a dedicated right turn lane with no parallel/conflicting crosswalk, an FYA would not be appropriate. A circular green or green arrow (depending on geometry) would be the appropriate signal display. If this right turn has a dedicated phase with a green arrow, the opposing left turn would not have a FYA active at the same time due to the turning conflict.
Quote from: US81 on March 15, 2015, 02:34:47 PM
Quote from: jeffandnicole on March 15, 2015, 02:26:12 PM
I think colorblind people can see yellow. So even if they couldn't see the exact color of the green arrow, they would know when it is yellow.
Many but not all; there are many kinds of color-blindness. There are those who see the world only in shades of grey.
I know with both forms of red-green color blindness (protanopia and deuteranopia), you cannot distinguish between reds, yellows, and greens. With blue-yellow color blindness (tritanopia), however, yellow and green are distinguishable, although yellow doesn't actually appear yellow (looks pinkish) and blues look greenish.
Charlottesville, VA, has them all over town. Last time I was up there, I wanted to know if they still had them and they do. I think that's a really cool way to use just four lamps, and it seems more intuitive than the FYA.
Quite common in Western New York. Region 5 installed them until 3-4 years ago and some of the counties (Erie and Monroe), cities, and towns use them for the majority of PPLTs. Heck, Erie County installed some as recently as last summer.
Quote from: Pink Jazz on March 15, 2015, 08:41:12 PM
Quote from: US81 on March 15, 2015, 02:34:47 PM
Quote from: jeffandnicole on March 15, 2015, 02:26:12 PM
I think colorblind people can see yellow. So even if they couldn't see the exact color of the green arrow, they would know when it is yellow.
Many but not all; there are many kinds of color-blindness. There are those who see the world only in shades of grey.
I know with both forms of red-green color blindness (protanopia and deuteranopia), you cannot distinguish between reds, yellows, and greens. With blue-yellow color blindness (tritanopia), however, yellow and green are distinguishable, although yellow doesn't actually appear yellow (looks pinkish) and blues look greenish.
Achromatopsia (total absence of color in vision) that I alluded to earlier is actually rather rare.
Southeastern PA used to have bimodal G/Y arrow signalheads on many a few of their signalized intersections but most if not all of them have since been replaced with the now-more common 5-head doghouse signalheads
Quote from: PHLBOS on March 16, 2015, 11:37:35 AM
Southeastern PA used to have bimodal G/Y arrow signalheads on many of their signalized intersections but most if not all of them have since been replaced with the now-more common 5-head doghouse signalheads
Wait, really? All the 4-section protected/permissive left turn signals I've seen there have just been R-Y-G-GA signals where the green arrow just goes off after the left turn phase is over.
Quote from: Ian on March 16, 2015, 01:53:02 PM
Quote from: PHLBOS on March 16, 2015, 11:37:35 AM
Southeastern PA used to have bimodal G/Y arrow signalheads on many a few of their signalized intersections but most if not all of them have since been replaced with the now-more common 5-head doghouse signalheads
Wait, really? All the 4-section protected/permissive left turn signals I've seen there have just been R-Y-G-GA signals where the green arrow just goes off after the left turn phase is over.
Many years ago, the signal at the US 13/PA 420 intersection in Prospect Park (facing US 13 southbound) indeed had a 4-section signal head with the bimodal left-arrow at the bottom. I remember that one vividly during the 90s back when I drove to work an a daily basis.
Quote from: PHLBOS on March 16, 2015, 03:19:59 PM
Quote from: Ian on March 16, 2015, 01:53:02 PM
Quote from: PHLBOS on March 16, 2015, 11:37:35 AM
Southeastern PA used to have bimodal G/Y arrow signalheads on many a few of their signalized intersections but most if not all of them have since been replaced with the now-more common 5-head doghouse signalheads
Wait, really? All the 4-section protected/permissive left turn signals I've seen there have just been R-Y-G-GA signals where the green arrow just goes off after the left turn phase is over.
Many years ago, the signal at the US 13/PA 420 intersection in Prospect Park (facing US 13 southbound) indeed had a 4-section signal head with the bimodal left-arrow at the bottom. I remember that one vividly during the 90s back when I drove to work an a daily basis.
Interesting, never knew about that. I wonder why PA didn't use more of them as opposed to just having the green arrow.
Quote from: Ian on March 16, 2015, 08:40:34 PM
Quote from: PHLBOS on March 16, 2015, 03:19:59 PMMany years ago, the signal at the US 13/PA 420 intersection in Prospect Park (facing US 13 southbound) indeed had a 4-section signal head with the bimodal left-arrow at the bottom. I remember that one vividly during the 90s back when I drove to work an a daily basis.
Interesting, never knew about that. I wonder why PA didn't use more of them as opposed to just having the green arrow.
Such was probably done on an experimental basis. IIRC, a couple other examples
were at the PA 420/MacDade Blvd. (signalhead faced westbound MacDade traffic) and along Ridge Pike in Montgomery County (near I-476).