AARoads Forum

National Boards => General Highway Talk => Traffic Control => Topic started by: Bryant5493 on November 03, 2010, 08:14:13 PM

Title: Flashing Red/Flashing Yellow
Post by: Bryant5493 on November 03, 2010, 08:14:13 PM
When a traffic light is out -- flashing red on one street and flashing yellow on another -- is all traffic to treat the intersection as an all-way stop? Or does the all-way stop occur when a signal's blacked-out on all segments? I try to go with the flow of traffic, so as not to get killed. :happy: I know that flashing yellow means slow down and watch for traffic; while the flashing red means stop. So...


Be well,

Bryant
Title: Re: Flashing Red/Flashing Yellow
Post by: KEK Inc. on November 03, 2010, 08:17:13 PM
To answer your question, no.  The flashing yellow has automatic right-of-way.  When the light is down, they usually default to flashing red in all directions, unless it's a major intersection, in which they may do the flashing yellow and flashing red.  (Not all areas do this.) 

If the signal is off without gaffer or caution tape blocking the lenses, then it's a stop sign. 
Title: Re: Flashing Red/Flashing Yellow
Post by: Duke87 on November 03, 2010, 08:19:25 PM
Only flashing red means stop. Flashing yellow in this case pretty much just means "caution: intersection" (though in some other contexts it can mean yield).

A completely dark signal, by the book, is supposed to be treated as an all-way stop. However, in cases where there is a clear major main street and minor side street, drivers will typically treat it like a stop for the side street only (which makes sense).
Title: Re: Flashing Red/Flashing Yellow
Post by: US71 on November 03, 2010, 10:06:26 PM
Quote from: Duke87 on November 03, 2010, 08:19:25 PM
Only flashing red means stop. Flashing yellow in this case pretty much just means "caution: intersection" (though in some other contexts it can mean yield).


In Arkansas it means: "dangerous intersection with many fatalities, but AHTD is too cheap for a real traffic signal"    X-(
Title: Re: Flashing Red/Flashing Yellow
Post by: roadfro on November 04, 2010, 04:10:52 AM
I've never heard of a traffic signal that has flashing red for one street and flashing yellow on another street when there's a problem with the signal. Most controller cabinets are designed and wired in such a way that if there is a controller problem, the conflict monitor makes the signal heads default to flashing red in all directions--this is done as an all-way red flash (treated as an all-way stop) is typically the best fail-safe option for safety reasons.

Flashing red/Flashing yellow is used in low-volume situations (typically at night) that wouldn't warrant full stop-and-go signal modes. Only the approaches with flashing red are required to come to a complete stop.
Title: Re: Flashing Red/Flashing Yellow
Post by: realjd on November 04, 2010, 08:43:38 AM
Quote from: roadfro on November 04, 2010, 04:10:52 AM
I've never heard of a traffic signal that has flashing red for one street and flashing yellow on another street when there's a problem with the signal. Most controller cabinets are designed and wired in such a way that if there is a controller problem, the conflict monitor makes the signal heads default to flashing red in all directions--this is done as an all-way red flash (treated as an all-way stop) is typically the best fail-safe option for safety reasons.

Around here, many will default to yellow in one direction and red in the other. It's usually intersections with a well defined major and a well defined minor road though. Think parking lots, neighborhoods entrances, and other similar types of situations.
Title: Re: Flashing Red/Flashing Yellow
Post by: Bryant5493 on November 04, 2010, 08:46:03 AM
@roadfro:

Most of the signals that I've encountered in the Atlanta area default to flashing red/flashing yellow when they malfunction, when they should default to the flashing red in all directions (and these are major intersections).


Be well,

Bryant
Title: Re: Flashing Red/Flashing Yellow
Post by: US71 on November 04, 2010, 08:52:57 AM
Another example of the 4-Way Red is in Van Buren, AR: Fayetteville Rd/8th St crosses Main St at the Arkansas-Missouri Railroad. The signals switch to 4-Way Flashing Red when there is a train.

http://maps.google.com/maps?q=van+buren,+ar&hl=en&client=opera&ie=UTF8&hq=&hnear=Van+Buren,+Crawford,+Arkansas&gl=us&ei=uavSTPn0MIPGlQeEy5XvDQ&ved=0CBkQ8gEwAA&ll=35.43674,-94.352582&spn=0.005219,0.008229&z=17&layer=c&cbll=35.436773,-94.352436&panoid=HKuv1W4kQdU_Uax5t5M9OA&cbp=12,298.71,,0,5
Title: Re: Flashing Red/Flashing Yellow
Post by: Dr Frankenstein on November 04, 2010, 12:01:06 PM
There's only one signal around here that I know of that defaults to a 2 way stop... and it was installed two months ago.
Title: Re: Flashing Red/Flashing Yellow
Post by: kj3400 on November 04, 2010, 12:54:20 PM
Coincidentally enough, the light at the nearest corner from my house defaulted to flashing yellow/red this morning. But a traffic cop was there so the traffic followed his orders. Interestingly too, he tried to follow the signal's original sequence (Wb traffic has a doghouse signal and they get a protected green).
Title: Re: Flashing Red/Flashing Yellow
Post by: hm insulators on November 09, 2010, 12:40:38 PM
Quote from: roadfro on November 04, 2010, 04:10:52 AM
I've never heard of a traffic signal that has flashing red for one street and flashing yellow on another street when there's a problem with the signal.

I've never heard of that, either. Everywhere I've driven (primarily Hawaii, California, Arizona), if a traffic signal goes kaplooie, then it automatically switches to four-way flashing red.
Title: Re: Flashing Red/Flashing Yellow
Post by: mightyace on November 09, 2010, 12:56:18 PM
It's a moot point here in Middle Tennessee as the main cause of signal problems is power outages, usually due to a storm.

In that case, all signals are dark.  :colorful:
Title: Re: Flashing Red/Flashing Yellow
Post by: Bryant5493 on November 09, 2010, 08:01:26 PM
Also, with the flashing red/yellow set-up, what doesn't help is that traffic reporters say treat these type of intersections as four-way stops (on a malfunction and they're flashing red/yellow).


Be well,

Bryant
Title: Re: Flashing Red/Flashing Yellow
Post by: realjd on November 10, 2010, 08:20:40 AM
Quote from: Bryant5493 on November 09, 2010, 08:01:26 PM
Also, with the flashing red/yellow set-up, what doesn't help is that traffic reporters say treat these type of intersections as four-way stops (on a malfunction and they're flashing red/yellow).

I've never once heard that for a light that's flashing yellow, only for lights that are out completely. How is a light that goes into a fail-safe state of yellow/red any different than a light that switches to yellow/red at night?
Title: Re: Flashing Red/Flashing Yellow
Post by: Bryant5493 on November 10, 2010, 08:54:15 AM
^^

That's agreeable, but yeah...


Be well,

Bryant
Title: Re: Flashing Red/Flashing Yellow
Post by: agentsteel53 on November 10, 2010, 10:35:38 AM
Quote from: realjd on November 10, 2010, 08:20:40 AM

I've never once heard that for a light that's flashing yellow, only for lights that are out completely. How is a light that goes into a fail-safe state of yellow/red any different than a light that switches to yellow/red at night?

traffic level in at the time of fail-safe may not warrant the red/yellow.  Side street traffic may get stuck because there are no openings for them to even turn right.  Red/yellow works because at the time of that mode of operation, traffic levels are sufficiently low (say, one car a minute or fewer) that the side street traffic can safely and conveniently make right turn, left turn, and straight through.
Title: Re: Flashing Red/Flashing Yellow
Post by: roadfro on November 13, 2010, 12:12:43 AM
Quote from: realjd on November 10, 2010, 08:20:40 AM
How is a light that goes into a fail-safe state of yellow/red any different than a light that switches to yellow/red at night?

Legally speaking, it's not any different.

Operationally speaking, if a signal goes into a fail-safe red/yellow flash mode during a peak travel period, there will be far less opportunity for a vehicle on the side street to clear the intersection. This is a disadvantage, as agentsteel alluded to, especially if the "side street" isn't a minor approach that would experience significant delays in a two-way stop scenario.