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One-aspect traffic lights (aka "perpetual green light")

Started by KCRoadFan, February 13, 2022, 11:45:37 PM

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Bitmapped

Quote from: 1995hoo on February 19, 2022, 09:03:42 AM
Quote from: Dirt Roads on February 18, 2022, 12:14:37 PM
These were common in Charleston, West Virginia, back in the 1960s and 1970s.  Both the upriver lanes of Southside Expressway (southbound WV-61) and Kanawha Boulevard (sometimes Alt US-60, eastbound lanes) were equipped with full signals in the left lane and thru perpetual green signals on the right lanes (with Bots Dots between the lanes) at most of the signalized intersections.  It was funny to see out-of-towners pass on the left only to get snagged by the traffic signal, whereas locals just doodled in the right lane but kept moving.  There were so many in a row on The Boulevard that during rush hour, it effectively created a single lane eastbound with a dedicated turn lane.  By the mid-1970s, so many businesses were moving out of the West End that there was hardly any need for left turns off the Boulevard during the morning rush hour.

As of 2017, there was at least one such signal remaining at the corner of Kanawha and Greenbrier near the State Capitol. I had never been to Charleston before and we made a left from Greenbrier onto southbound Kanawha and as I completed my turn someone came FLYING through in the other lane going extremely fast (easily 60 mph or more). Startled the shit out of me because I wasn't aware of the configuration and the guy appeared out of nowhere very quickly. At least there were plastic bollards between the lanes (exactly what some comments up the thread have suggested are necessary in these situations).

There may be other such setups remaining in Charleston, but that's the only one I remember encountering.

Most of the Kanawha Boulevard ones in Charleston were removed a couple years ago to improve pedestrian access to the river. There are still some along MacCorkle Avenue (WV 61). There's also one on US 60 just east of the WV Turnpike at Campbells Creek Drive.

There are some other instances throughout the state, including one about a mile from my house in Morgantown at WV 7 and I-68.




Dirt Roads

#27
Quote from: Dirt Roads on February 18, 2022, 12:14:37 PM
These were common in Charleston, West Virginia, back in the 1960s and 1970s.  Both the upriver lanes of Southside Expressway (southbound WV-61) and Kanawha Boulevard (sometimes Alt US-60, eastbound lanes) were equipped with full signals in the left lane and thru perpetual green signals on the right lanes (with Bots Dots between the lanes) at most of the signalized intersections.  It was funny to see out-of-towners pass on the left only to get snagged by the traffic signal, whereas locals just doodled in the right lane but kept moving.  There were so many in a row on The Boulevard that during rush hour, it effectively created a single lane eastbound with a dedicated turn lane.  By the mid-1970s, so many businesses were moving out of the West End that there was hardly any need for left turns off the Boulevard during the morning rush hour.

Quote from: 1995hoo on February 19, 2022, 09:03:42 AM
As of 2017, there was at least one such signal remaining at the corner of Kanawha and Greenbrier near the State Capitol. I had never been to Charleston before and we made a left from Greenbrier onto southbound Kanawha and as I completed my turn someone came FLYING through in the other lane going extremely fast (easily 60 mph or more). Startled the shit out of me because I wasn't aware of the configuration and the guy appeared out of nowhere very quickly. At least there were plastic bollards between the lanes (exactly what some comments up the thread have suggested are necessary in these situations).

There may be other such setups remaining in Charleston, but that's the only one I remember encountering.

Quote from: Bitmapped on February 19, 2022, 06:31:56 PM
Most of the Kanawha Boulevard ones in Charleston were removed a couple years ago to improve pedestrian access to the river. There are still some along MacCorkle Avenue (WV 61). There's also one on US 60 just east of the WV Turnpike at Campbells Creek Drive.

There are some other instances throughout the state, including one about a mile from my house in Morgantown at WV 7 and I-68.

And speaking of MacCorkle Avenue (a.k.a. the Southside Expressway), I forgot about the two downriver (northbound WV-61) locations:  one at the Thayer Street loopback around the Amtrak station for the South Side Bridge, and the other nextdoor at the north end of Oakwood Road (US-119 Connector).  The latter one is unusual, as it is the official end of Corridor G rather than making a straightline connection to I-64/US-119 northbound.

interstatefan990

Multi-lane roundabouts are an abomination to mankind.

rellis97


Big John


US 89

Quote from: US 89 on February 17, 2022, 08:22:34 AM
Quote from: ran4sh on February 17, 2022, 01:13:19 AM
Quote from: US 89 on February 13, 2022, 11:55:57 PM
I know there is a one-aspect green ball somewhere in the Atlanta metro area, but I cannot for the life of me remember where it is.

There are several in the Atlanta area, the typical use case is at a partial diamond interchange where there is sufficient left-turn demand onto the onramp for a signal, in which case the single-aspect green lights are mounted over the straight-thru lanes. Examples: Sidney Marcus at SR 400 (https://goo.gl/maps/BCSYDgfB3j9JyuKz8), Peachtree-Dunwoody at I-285, Glenridge Dr at I-285, etc.

The SR 141 (Peachtree Industrial) and I-285 interchange has them too (https://goo.gl/maps/J3gMNPhTQpGqJhaLA)

Yeah, I knew about most of those, especially the one on Peachtree Industrial which I drive through fairly often - but those are all one-aspect green arrows. I’m almost positive there is at least one single circular green ball indication somewhere in the north half of the metro, and I feel like it’s at some sort of free right type movement.

Update: I found what I'm pretty sure I was remembering. It is in fact not in the Atlanta area, but on US 80 at Islands Expressway in Savannah:


MASTERNC

Quote from: 1995hoo on February 19, 2022, 09:03:42 AM
Quote from: Dirt Roads on February 18, 2022, 12:14:37 PM
These were common in Charleston, West Virginia, back in the 1960s and 1970s.  Both the upriver lanes of Southside Expressway (southbound WV-61) and Kanawha Boulevard (sometimes Alt US-60, eastbound lanes) were equipped with full signals in the left lane and thru perpetual green signals on the right lanes (with Bots Dots between the lanes) at most of the signalized intersections.  It was funny to see out-of-towners pass on the left only to get snagged by the traffic signal, whereas locals just doodled in the right lane but kept moving.  There were so many in a row on The Boulevard that during rush hour, it effectively created a single lane eastbound with a dedicated turn lane.  By the mid-1970s, so many businesses were moving out of the West End that there was hardly any need for left turns off the Boulevard during the morning rush hour.

As of 2017, there was at least one such signal remaining at the corner of Kanawha and Greenbrier near the State Capitol. I had never been to Charleston before and we made a left from Greenbrier onto southbound Kanawha and as I completed my turn someone came FLYING through in the other lane going extremely fast (easily 60 mph or more). Startled the shit out of me because I wasn't aware of the configuration and the guy appeared out of nowhere very quickly. At least there were plastic bollards between the lanes (exactly what some comments up the thread have suggested are necessary in these situations).

There may be other such setups remaining in Charleston, but that's the only one I remember encountering.

The Greenbriar ones are up and down a mountain.  Downhill traffic splits where the left lane goes through the signalized intersection (along with a left turn lane) while the right lane is free flowing with a green arrow.

https://goo.gl/maps/qjwsUg5SqZ1sVKBJ9

I know of one example in Plymouth Meeting, PA.  As shown in GSV, there is a sign telling thru traffic to keep moving, while there is no signal for them ahead (just for the left turn).

https://goo.gl/maps/wHD3dpXzrTY7nrm46

A close second is a light on US 202 around the King of Prussia Mall where mall traffic can only turn right onto 202.  However, there is a pedestrian signal, so this light is not perpetually green (albeit it rarely turns red for NB traffic).

https://goo.gl/maps/2na8gyLUfX9av4kt9

JoePCool14

Here's another perpetual turn arrow in Des Plaines, Illinois:
https://goo.gl/maps/QqNUBTJFYKrqxHUM8

One of the arrows is out, and there's only one left. So if that one goes, I guess it won't be perpetual anymore.

Also in Illinois, up in Libertyville on IL-176:
https://goo.gl/maps/vLxbwfva8n72pRjQ7

I question why this one even needs to exist at all. The protected-only left is overkill here.

:) Needs more... :sombrero: Not quite... :bigass: Perfect.
JDOT: We make the world a better place to drive.
Travel Mapping | 60+ Clinches | 260+ Traveled | 8000+ Miles Logged

kphoger

Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

abefroman329

If the goal is to keep traffic moving, then they certainly do better at that than the KEEP MOVING signs that are (were?) all over the place in GA

roadfro

Quote from: kphoger on March 16, 2022, 12:04:38 PM
While we're talking about Illinois...

I-90 @ US-20 (Hampshire)

I question why this one even needs to exist at all. It appears that the green aspects aren't even fully visible until you're already within the pork chop area, where it should be painfully obvious that it's a dedicated turn...and by the time you see them, the geometry seems fairly obvious that you have an added lane and need not stop...
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

kphoger

Quote from: roadfro on March 16, 2022, 04:14:11 PM

Quote from: kphoger on March 16, 2022, 12:04:38 PM
While we're talking about Illinois...

I-90 @ US-20 (Hampshire)

I question why this one even needs to exist at all. It appears that the green aspects aren't even fully visible until you're already within the pork chop area, where it should be painfully obvious that it's a dedicated turn...and by the time you see them, the geometry seems fairly obvious that you have an added lane and need not stop...

I think, legally, one would still be required to stop for the main signal without those constant arrows.

Incidentally, this location was the first time I had ever seen a single-aspect stoplight–back in 2003 or so.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

andrepoiy

#38
Here's a strange one that I found in Ontario, I don't think I've ever seen such a configuration anywhere else.

It's a permissive green that sometimes gets a protected arrow, but the green balls are eternal. Notice that there also isn't a signal mounted on the right side. Strange.




Here's a perpetual green, with permissive/protected left, but with normal signal configs


jakeroot

Quote from: kphoger on March 16, 2022, 04:17:13 PM

Quote from: roadfro on March 16, 2022, 04:14:11 PM

Quote from: kphoger on March 16, 2022, 12:04:38 PM
While we're talking about Illinois...

I-90 @ US-20 (Hampshire)

I question why this one even needs to exist at all. It appears that the green aspects aren't even fully visible until you're already within the pork chop area, where it should be painfully obvious that it's a dedicated turn...and by the time you see them, the geometry seems fairly obvious that you have an added lane and need not stop...

I think, legally, one would still be required to stop for the main signal without those constant arrows.

Definitely not, it's a simple right turn slip lane, and just like every other one that doesn't explicitly have a stop line and signal pointed at it, it is controlled separately from the signal. In this case, to ensure drivers keep moving, they've added green arrows. As it is more often common than not for slip lanes to have a yield sign, or in the case of Illinois, a signal, apparently they decided that a constant burning green arrow would be the best way to keep drivers moving; many states use regulatory signage ("right turn does not stop", "right turn keep moving", etc). I personally think what Illinois has done here is actually a lot cleaner than using a sign.

kphoger

Quote from: jakeroot on March 16, 2022, 05:47:21 PM
it's a simple right turn slip lane, and just like every other one that doesn't explicitly have a stop line and signal pointed at it, it is controlled separately from the signal. In this case, to ensure drivers keep moving, they've added green arrows. As it is more often common than not for slip lanes to have a yield sign, or in the case of Illinois, a signal, apparently they decided that a constant burning green arrow would be the best way to keep drivers moving

The bolded phrase is what I had in mind.  I don't think I've ever seen a slip lane without some form of traffic control device in the state of Illinois.  This leads me to think the slip lane is actually considered part of the intersection there.

More generally, though, I haven't ever looked into the vehicle code to see how slip lanes are legally treated, and it wouldn't surprise me at all if there's no specific carve-out that exempts them from stop-on-red requirements.  That is to say, I find it entirely likely that, legally speaking, slip lanes are not actually "controlled separately from the signal".  Not saying it's definitely the case, but I haven't explored that detail of the legal code.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

US 89

US 280 at Cherokee Rd in the Birmingham suburbs also has a full set of perma-green balls


jay8g

Lynnwood has a ramp meter with perpetual green for the HOV lanes (when the ramp meters are on).

Aberdeen has a perpetual green right turn arrow at a non-signalized intersection (essentially a "stop except right turns" situation, but without any signage).

jakeroot

Quote from: jay8g on March 27, 2022, 02:24:25 AM
Aberdeen has a perpetual green right turn arrow at a non-signalized intersection (essentially a "stop except right turns" situation, but without any signage).

Now that is cool. There's no way that's MUTCD compliant, but still very cool. Really only works without crosswalks, though, which is less than ideal.

JoePCool14

Quote from: jakeroot on March 27, 2022, 03:37:39 AM
Quote from: jay8g on March 27, 2022, 02:24:25 AM
Aberdeen has a perpetual green right turn arrow at a non-signalized intersection (essentially a "stop except right turns" situation, but without any signage).

Now that is cool. There's no way that's MUTCD compliant, but still very cool. Really only works without crosswalks, though, which is less than ideal.

Doesn't Michigan sometimes use that setup, except that the arrow is flashing and yellow?

:) Needs more... :sombrero: Not quite... :bigass: Perfect.
JDOT: We make the world a better place to drive.
Travel Mapping | 60+ Clinches | 260+ Traveled | 8000+ Miles Logged

Bitmapped

Quote from: jakeroot on March 27, 2022, 03:37:39 AM
Quote from: jay8g on March 27, 2022, 02:24:25 AM
Aberdeen has a perpetual green right turn arrow at a non-signalized intersection (essentially a "stop except right turns" situation, but without any signage).

Now that is cool. There's no way that's MUTCD compliant, but still very cool. Really only works without crosswalks, though, which is less than ideal.

PA sometimes does flashing red signals with a green ball for continuous right turns. I've seen them a couple times but the one that comes to mind is US 62/PA 8 at Franklin: https://goo.gl/maps/ufJ9XV39fpzHKnm56

Buck87


michravera

Quote from: KCRoadFan on February 13, 2022, 11:45:37 PM
Around the Kansas City metro, where I live, I have seen numerous signalized intersections where the cross-street only goes left, and while the left lane has a standard left-turn signal, the right lanes have this weird one-aspect signal that is simply a perpetual green arrow. Here they are, with Street View links:

Metcalf Avenue southbound at Blue Valley Parkway in Overland Park - https://www.google.com/maps/@38.9148542,-94.6688298,3a,37.5y,185.79h,89.21t/data=!3m6!1e1!3m4!1sqbAC7rh3FLrwD-8xa5Uo3g!2e0!7i16384!8i8192

US 56 westbound at Old 56 Highway on the east side of Gardner, near New Century Air Center - https://www.google.com/maps/@38.8132529,-94.9036987,3a,37.5y,220.79h,90.18t/data=!3m6!1e1!3m4!1sWsfIh7IdhAxr18Ovxy07UQ!2e0!7i16384!8i8192

7th Street northbound at the westbound I-70 on-ramp in KCK - https://www.google.com/maps/@39.0953935,-94.6260578,3a,75y,2h,102.44t/data=!3m6!1e1!3m4!1sLM6dTBA3aFYWkvdFBIJ_ZA!2e0!7i16384!8i8192

US 24/40 (State Avenue) westbound at the southbound K-7 on-ramp in Bonner Springs - https://www.google.com/maps/@39.116132,-94.8963941,3a,37.5y,269.06h,96.28t/data=!3m6!1e1!3m4!1sTvai9to8O_YP29YkFJU30g!2e0!7i16384!8i8192

Of note, all four of these signals are on the Kansas side of the metro. Is this a Kansas thing in particular? Also, where else throughout the country have you seen such installations? I'm sure there must be at least a few of them out there somewhere.

Although I have seen an example of what the OP describes near William Land Park (right lane goes through and usually turns right) and several streets in the 30s and 40s that bend at Folsom Blvd (perpetual green light favors through traffic continuing on the jog and thouse turning right onto one of those streets) in Sacramento, my favorite was a near miss at the light at what was then Manlove Rd (today S Watt Ave) crossing Jackson Rd (CASR-16). Later at night when I was going to work an allnight shift, the light would heavily favor and would stay green for Manlove Rd, but, because of high speed and light vehicles and imperfect sensors, the lights would do a "clean up" cycle every couple of minutes to make sure that traffic on CASR-16 eventually got a chance to proceed. I would frequently (because I left for work at alomst the same time every night and traffic was very predictable) see the light on Manlove turn yellow against me and then green when I tripped the (maybe second?) sensor.  The first couple of times I wasn't sure of what I saw, but it happened often enough that I was eventually sure.

Max can probably say whether these same phenomena occur today, since I haven't really been in Sacramento except to visit family or attend a Bridge tournament since 1991.

jakeroot

Quote from: JoePCool14 on March 27, 2022, 10:28:07 AM
Quote from: jakeroot on March 27, 2022, 03:37:39 AM
Quote from: jay8g on March 27, 2022, 02:24:25 AM
Aberdeen has a perpetual green right turn arrow at a non-signalized intersection (essentially a "stop except right turns" situation, but without any signage).

Now that is cool. There's no way that's MUTCD compliant, but still very cool. Really only works without crosswalks, though, which is less than ideal.

Doesn't Michigan sometimes use that setup, except that the arrow is flashing and yellow?
Quote from: Bitmapped on March 27, 2022, 11:20:51 AM
PA sometimes does flashing red signals with a green ball for continuous right turns. I've seen them a couple times but the one that comes to mind is US 62/PA 8 at Franklin: https://goo.gl/maps/ufJ9XV39fpzHKnm56

I guess it doesn't surprise me that it's used on a semi regular basis, although I highly doubt new installations are still popping up, since the whole "no crosswalk" thing is a bit problematic for a neighborhood setting.

Michigan's version with a flashing yellow arrow is pretty cool, if it's a thing. That would actually allow for a crosswalk.

TheHighwayMan3561

self-certified as the dumbest person on this board for 5 years running



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