Horizontal Traffic Lights

[jeffandnicole]

There's one on US 13/40 at the intersection with DE 273 near an airport.
Why DelDOT decided to use them there is beyond me.

Perhaps because it's near an airport?

He's referring to this setup.  The only thing I see is that spanwire is lower than the others, so horizontal lights don't need as much height.  Even though the air traffic pattern takes planes directly over this intersection at a low altitude (note the metal standard rising from the traffic island which holds the air traffic guiding lights), there is nothing else unique regarding the traffic lights themselves. In fact, these specific horizontal lights wouldn't even be in an aircraft's line of sight.  The ones facing 13/40 North/East would be much more visible to aircraft.

[jakeroot]

Here is an example of the R-Y-G-Y-R horizontal signal I was talking about.  As far as I know this is the only one that still exists in the Sacramento area http://goo.gl/maps/0mOUV

The agencies in the Sacramento area hate putting a decent number of signal heads over the road so much they will instead take the chances with liability for nonstandard designs?  Interesting.

I don't think anything is wrong here. The second signal head is California-standard pole-mounted to the right. The double-red is not unheard of. Plenty of signals have them (albeit on top of each other). The double-amber is not something I've seen before, and you could make an argument that a liability arises, but for all we know, this intersection might have a problem with people jumping the red/speeding up on amber and they want a higher amount of "exposure" to motorists.

Also, what in California is standard? 

[roadfro]

Here is an example of the R-Y-G-Y-R horizontal signal I was talking about.  As far as I know this is the only one that still exists in the Sacramento area http://goo.gl/maps/0mOUV

The agencies in the Sacramento area hate putting a decent number of signal heads over the road so much they will instead take the chances with liability for nonstandard designs?  Interesting.

I don't think anything is wrong here. The second signal head is California-standard pole-mounted to the right. The double-red is not unheard of. Plenty of signals have them (albeit on top of each other). The double-amber is not something I've seen before, and you could make an argument that a liability arises, but for all we know, this intersection might have a problem with people jumping the red/speeding up on amber and they want a higher amount of "exposure" to motorists.

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

If there is an issue with jumping the red, they could use a standard R-R-Y-G display instead. To me, they should just slap a standard 3-section display up there and call it a day.

[DaBigE]

Here is an example of the R-Y-G-Y-R horizontal signal I was talking about.  As far as I know this is the only one that still exists in the Sacramento area http://goo.gl/maps/0mOUV

The agencies in the Sacramento area hate putting a decent number of signal heads over the road so much they will instead take the chances with liability for nonstandard designs?  Interesting.

I don't think anything is wrong here. The second signal head is California-standard pole-mounted to the right. The double-red is not unheard of. Plenty of signals have them (albeit on top of each other). The double-amber is not something I've seen before, and you could make an argument that a liability arises, but for all we know, this intersection might have a problem with people jumping the red/speeding up on amber and they want a higher amount of "exposure" to motorists.

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Madison, WI has a rare mounting of a red on both ends of the horizontal, but that is tied into the railroad crossing signals (installed before the cantilevered signals were erected). Until the mid-2000s, the traffic signals doubled as railroad crossing signals, with the pedestal mounted signals going into a flashing red phase during a train event. You can still see the original crossbucks on the pole for the horizontal signals.

[roadfro]

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Say a red/green colorblind driver is new to the area and unfamiliar with this particular signal. The colorblind driver knows that a standard horizontally-mounted signal head always has circular red on the far left position and circular green in the far right position of the head. When this driver pulls up to this signal and it is red, simultaneously displaying a lighted circular indication in both the far left and far right sections of the signal head (where red and green, respectively, should be placed) what are they supposed to think? It will look like a conflict.

[jakeroot]

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Say a red/green colorblind driver is new to the area and unfamiliar with this particular signal. The colorblind driver knows that a standard horizontally-mounted signal head always has circular red on the far left position and circular green in the far right position of the head. When this driver pulls up to this signal and it is red, simultaneously displaying a lighted circular indication in both the far left and far right sections of the signal head (where red and green, respectively, should be placed) what are they supposed to think? It will look like a conflict.

My rough guess is that they'll be momentarily confused, then will look around to see what other cars are doing. This isn't a life-or-death situation here. Confusion doesn't immediately lead to huge traffic collision. I would assume color-blind individuals have trained themselves to look at more than just the traffic signal head.

Also, does red-green color blindness switch red and green? Not actually sure how that works. Wouldn't they just know that if either side was green, that actually meant they were red? I seriously have no idea what red-green color-blindness means.

[DaBigE]

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Say a red/green colorblind driver is new to the area and unfamiliar with this particular signal. The colorblind driver knows that a standard horizontally-mounted signal head always has circular red on the far left position and circular green in the far right position of the head. When this driver pulls up to this signal and it is red, simultaneously displaying a lighted circular indication in both the far left and far right sections of the signal head (where red and green, respectively, should be placed) what are they supposed to think? It will look like a conflict.

They should treat it with the fail-safe assumption in a potential conflict: that it is red and only red. No different than coming up to a darkened signal in a power outage. You treat it as a stop sign.

Color-deficiency aside, what would you do if you were approaching an intersection that you weren't exactly sure of the traffic control signal? Blast right through it? I doubt it.

Not quite the same case, but a couple years ago a lady received a ticket for running a red light. She tried to use the excuse that she couldn't see any of the signals, (a moist, blowing snowfall had occurred earlier and had coated some of the signal lenses such that they could not be easily seen). The LEO informed her she was supposed to treat it as a red light, stop, then look for clues as to what the light actually is (these types of snowstorms are usually very directional, so it is rare for more than one direction to have this problem at the same time). Her ticket held up in court.

[roadfro]

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Say a red/green colorblind driver is new to the area and unfamiliar with this particular signal. The colorblind driver knows that a standard horizontally-mounted signal head always has circular red on the far left position and circular green in the far right position of the head. When this driver pulls up to this signal and it is red, simultaneously displaying a lighted circular indication in both the far left and far right sections of the signal head (where red and green, respectively, should be placed) what are they supposed to think? It will look like a conflict.

My rough guess is that they'll be momentarily confused, then will look around to see what other cars are doing. This isn't a life-or-death situation here. Confusion doesn't immediately lead to huge traffic collision. I would assume color-blind individuals have trained themselves to look at more than just the traffic signal head.

Yes, they would likely need to rely on other context clues to figure out what is going on. However, in a country where there are standard signal patterns and conventions that remove any ambiguity, it seems reasonable to remove any such uncertainties like this.

Also, does red-green color blindness switch red and green? Not actually sure how that works. Wouldn't they just know that if either side was green, that actually meant they were red? I seriously have no idea what red-green color-blindness means.

My understanding of color blindness is that people who have it may have difficulty discerning the different color hues due to deformities in the parts of the eyes (cones?) that process color patterns. So it is not a true switch of the two colors, but more seeing a color and not being able to tell if it is one or the other.

Red-green I believe is one of the most common types of color blindness. Blue-yellow is another.

[jakeroot]

Red-green I believe is one of the most common types of color blindness. Blue-yellow is another.

Well, how convenient for us! 

[DaBigE]

The problem with that signal is that the standard for horizontal signals has circular red on the far left and green to the right. A driver with red/green color blindness (a common color blindness combination) could get confused by the layout of the signal heads--especially with the reds being on the outer ends where one can reasonably expect a red and a green to appear.

Except, unless the signal is malfunctioning (or possibly some kind of emergency preemption display), the red and green ball would never be lit at the same time. So in theory, colorblindness shouldn't be much of an issue.

Say a red/green colorblind driver is new to the area and unfamiliar with this particular signal. The colorblind driver knows that a standard horizontally-mounted signal head always has circular red on the far left position and circular green in the far right position of the head. When this driver pulls up to this signal and it is red, simultaneously displaying a lighted circular indication in both the far left and far right sections of the signal head (where red and green, respectively, should be placed) what are they supposed to think? It will look like a conflict.

My rough guess is that they'll be momentarily confused, then will look around to see what other cars are doing. This isn't a life-or-death situation here. Confusion doesn't immediately lead to huge traffic collision. I would assume color-blind individuals have trained themselves to look at more than just the traffic signal head.

Yes, they would likely need to rely on other context clues to figure out what is going on. However, in a country where there are standard signal patterns and conventions that remove any ambiguity, it seems reasonable to remove any such uncertainties like this.

I think we all can agree that this signaling practice is far from ideal and should be replaced.

My understanding of color blindness is that people who have it may have difficulty discerning the different color hues due to deformities in the parts of the eyes (cones?) that process color patterns. So it is not a true switch of the two colors, but more seeing a color and not being able to tell if it is one or the other.

Red-green I believe is one of the most common types of color blindness. Blue-yellow is another.

It's been nearly a decade since the class I had in college that discussed the implications of color-deficiency in the driving public, (our prof. wouldn't let us use the term color-blind, since it's technically not a "blindness"), so the details are a bit fuzzy. What else I do remember was that problems with the rods and cones in the eyes are the cause. And color-deficient drivers are the reason why all three indications have a bluish tinge to them (e.g., amber instead of a pure yellow).

[Scott5114]

Also, does red-green color blindness switch red and green? Not actually sure how that works. Wouldn't they just know that if either side was green, that actually meant they were red? I seriously have no idea what red-green color-blindness means.

There was a red-green colorblind kid at my high school. He told me that he perceives both red and green as a muddy brown.

There are some tools on the internet designed for testing websites that change a site's colorscheme to how it would be perceived by red-green and blue-yellow colorblind people.

[averill]

I do not know if any study has been done, but they are good for hurricanes and where overpasses generally block the standard type mount. They are even used under bridges where you do not have headroom to hang a traditional signal like under elevated subway lines or in SPUI setups.

Actually, with the Quebec shape coded symbol traffic signal, you only need two different lens housing. The square red obviously needs its own separate one. You would need something like pedestrian signal housing for that. But for the yellow diamond and green "ball", the standard for the green will work for the yellow. The round lenses could simply be coloured yellow or amber and then have the diamond silk screened or stencilled onto the ball lens. This would reduce costs a great deal.

I love these signals and have these lenses in my collection. I also have video of these, which I have filmed in Quebec. I am surprised that associations for the blind haven't pushed these signal lenses in the US for colour-blind drivers under the ADA. I really thought they would take hold in Canada. I know British Columbia was thinking of using them for a while. PEI does use them. They were used in New Brunswick and Nova Scotia, but never made it to wide spread use. They have since been replaced with standard signals in those provinces. In addition, Quebec stopped using them on provincially maintained highways, but is still legal, there. Still maintained in some municipalities. I have these provincial standards. By the way, these signals are placed in the horizontal position, which you show, and, vertical.

[mrfoxboy]

Some examples of a very common newer-style traffic light here in Moncton, NB, and a few variations:
http://goo.gl/maps/pwhCz Standard issue lights here, for protecting left-turns (green bimodal arrow flashes, then goes solid-yellow, then off). Similar cycles to PEI (I'll try to get video).

http://goo.gl/maps/igoqH Variant showing separated roadways. Sometimes there are five heads in the horizontal signal, sometimes four (this only happens on separated roadways.

http://goo.gl/maps/D7y36 Odd variant with an add-on horizontal signal on the left, due to poor sightlines.

http://goo.gl/maps/9P3wX Moncton used to always set up two horizontal signals until as late as the 80's. This is a rare nearly-untouched setup.

http://goo.gl/maps/H5axF Older signal, probably from the 60's or 70's, showing the wonky configurations that Moncton would go to to have the two horizontal signals, while still cheaping out on digging.

http://goo.gl/maps/Xu5kC This is hands-down the busiest intersection in town, despite the no-left-turn on the one side. Also double-left-turn-lanes on one of the legs, the first ones in the area, had such a high incidence of running the straight-only green (as it was the second setup in the city ever) that the city added a segment for a red left-turn arrow.

http://goo.gl/maps/AGbwV This is one of a couple of new super-sized signals. It might have cost more than expected (new signals planned and designed after these were set up like the first one, even on busier streets with double-left-turn lanes.)

http://goo.gl/maps/rCCkR A much older variation on the above. These were set up in 1990 when the separated roadway was built. The left two vertical signals are for left-turn (green and yellow arrows, but oddly a louvered red ball). The horizontal signal, as well as the vertical signal on the right of the divider, only show straight-through.
New Brunswick (specifically the metro Moncton area) definitely does the horizontal, but does the vertical too! 

[Quillz]

I'm currently in Santa Fe, NM for a few days, and saw many of the horizontal traffic lights. Only thing I don't like about them is the left arrow is to the right of the red light. Spatially, it threw me off a few times, since I expected the left arrow to be left of the red light. (The first time I saw this, I thought the light had turned green for all lanes for a split-second). Otherwise, I like the consistency (so far) of the traffic light installations throughout the city.

[David Jr.]

I've been on vacation in Pueblo, CO and I am currently in Amarillo, TX.  I went through Dumas, TX earlier today, and they have the horizontal traffic lights there.  However, here in Amarillo, where I am staying for the night, the traffic lights are vertical.

[jakeroot]

I've been on vacation in Pueblo, CO and I am currently in Amarillo, TX.  I went through Dumas, TX earlier today, and they have the horizontal traffic lights there.  However, here in Amarillo, where I am staying for the night, the traffic lights are vertical.

I think most of Texas uses horizontal traffic lights. So, I guess Amarillo is the oddity.

[Brian556]

Quote from Jakeroot:

I think most of Texas uses horizontal traffic lights. So, I guess Amarillo is the oddity.

TxDOT Dist. 2 (Ft Worth) uses vertical signals exclusively.

City of Dallas signals on old-style poles are vertical.
City Of Farmers Branch uses vertical on modern mast arms.

An old photograph shows four-section heads with a red on either end on SH 24 (now US 380) in Denton.

[jakeroot]

TxDOT Dist. 2 (Ft Worth) uses vertical signals exclusively.

City of Dallas signals on old-style poles are vertical.
City Of Farmers Branch uses vertical on modern mast arms.

An old photograph shows four-section heads with a red on either end on SH 24 (now US 380) in Denton.

That's why I said most of Texas, not all (District 2 represents roughly 4% of the state, Farmers Branch accounts for .001% of the state's population, and old signals don't count).

[David Jr.]

The intersection of N. 3rd St. and E. Main St. (OK 7/US. 77) in Davis, Oklahoma has horizontal traffic lights.

[Darkchylde]

Wornall Road, where it meets I-435, has horizontal lights for the movements that have just gone under the overpass, namely due to sight lines that vertical lights wouldn't be safe for.

[paulthemapguy]

Here's one in Joliet, IL.  It was just built a year and a half ago, and you can see why the signal's height was minimized; in the distance, you can see a diagonal airport runway whose flight path ends up right above the intersection.
https://goo.gl/maps/2NWAkHGm3qj

Another signal with sideways heads is at Laraway Road and 80th Av in Frankfort, because of overhead powerlines crossing the intersection diagonally.  Only the northbound approach has the sideways heads- and GSV hasn't been updated recently to show the new signal.  But here's the location- you can kind of tell based on the shadows shown by aerial imagery https://www.google.com/maps/@41.4845905,-87.8093796,103m/data=!3m1!1e3

Also, here's a set of sideways signal heads for a railroad underpass in Bloomington
https://goo.gl/maps/Xc7gxZje2rj

But sideways signal heads in Illinois are nonexistent except for cases like these; when you need to see under an overhead obstruction, or you want to limit a signal's protrusion into the sky.

Can we also add Florida to the list of states with widespread use of sideways signals?

[David Jr.]

These horizontal signals are in front of the Trump Taj Mahal in Atlantic City:

[US 89]

There are two in Utah that I know of. Both are at pedestrian bridges where clearance may be an issue. Otherwise, Utah is all vertical.
https://goo.gl/maps/eT1NzhcWgYR2
https://goo.gl/maps/fcXjT49uFep

[Rothman]

There are two in Utah that I know of. Both are at pedestrian bridges where clearance may be an issue. Otherwise, Utah is all vertical.
https://goo.gl/maps/eT1NzhcWgYR2
https://goo.gl/maps/fcXjT49uFep

Hm.  Although they are vertical now, I am pretty sure the traffic lights at Eagle Gate in SLC were at one point horizontal.

[MNHighwayMan]

Here's a bit of an odd one: these signals were turned horizontal because of the construction of a building immediately behind them. Probably two of very few, if not the only, horizontal signals in Iowa. This is (was? not sure if they're still there–I should probably go check) at 6th Ave and High St in downtown Des Moines. Picture is from January 2015.