Flashing yellow light in San Francisco

[mrsman]

As depicted in this GSV image, there is a flashing yellow light instead of a green light at the corner of Haight and Octavia in SF.

http://goo.gl/maps/LdF22

Can anyone tell me why this was done?

[jeffandnicole]

Maybe it's their way of getting your attention so you don't go straight into the opposing one-way street?

[citrus]

That, and I believe traffic WB on Haight turning SB on Octavia (towards the freeway) has a green arrow and therefore right-of-way.

That street view pic is already out of date. There's now a red bus-only lane heading EB there (it literally opened today: http://hoodline.com/2014/10/new-haight-street-muni-lane-opens-today). I have no idea how that affected traffic signals! The Market/Haight/Gough intersection 1 block east had been under construction for months, presumably for signal work there.

[AndyMax25]

We will soon be doing a similar treatment in Santa Monica where 2 one-way streets intersect into a 2-way road.  The 2 one-ways are both going towards the intersection.

A flashing yellow indicates to proceed thru the intersection with caution while making all legal movements. This is used since a green ball would indicate that thru movement is possible and green arrows would conflict with ped movements and would only work if a 3rd phase is added, which is not needed in this case due to low volumes.

LADOT prefers the flashing red.  This operation may be confusing since a flashing red signifies a 4-way stop condition which is not what is happening at the intersection.


iPhone

[florida]

There is also the same setup at 8th and Brannan.

The one-way direction receives priority over the two-way direction.

[Indyroads]

LADOT prefers the flashing red.  This operation may be confusing since a flashing red signifies a 4-way stop condition which is not what is happening at the intersection.


iPhone

Flashing Red does not always denote a all way stop. many intersections here in Indiana have flashing yellow for one road and and flashing red for the crossing road. This is also very common in California also.

[mrsman]

That, and I believe traffic WB on Haight turning SB on Octavia (towards the freeway) has a green arrow and therefore right-of-way.

That street view pic is already out of date. There's now a red bus-only lane heading EB there (it literally opened today: http://hoodline.com/2014/10/new-haight-street-muni-lane-opens-today). I have no idea how that affected traffic signals! The Market/Haight/Gough intersection 1 block east had been under construction for months, presumably for signal work there.

Indeed, that is what led me to do GSV in this area.  I read streetsblog LA (hate the politics and anti-car attitude, but at least they let you know what's going on with street changes) and there was a link to a streestsblog SF article about the bus lanes.

Flashing yellow is very interesting.  I guess it signifies that these people would never get the right of way, yet the safest time to turn would be if they only had to contend with opposing traffic (and turns are prohibited when Octavia gets the green).

But I'm not familiar with using it in this context.  Usually, I see it in a flashing red/flashing yellow intersection.

And usually where two one-ways meet in an opposing faction, they both have green lights.  One has to be aware not to go straight through, but essentially left turners should yield to peds and opposing right turners.

The only area that I'm familiar with (and hate) that has anything similar is Dupont Circle in D.C. with flashing yellow right arrows.  The only time you are allowed to turn into the circle from New Hampshire Avenue is a flashing yellow (because no turn on red) and you still have to watch out for pedestrians and traffic whipping around the circle.  Terribly unsafe.

[mrsman]

LADOT prefers the flashing red.  This operation may be confusing since a flashing red signifies a 4-way stop condition which is not what is happening at the intersection.


iPhone

Flashing Red does not always denote a all way stop. many intersections here in Indiana have flashing yellow for one road and and flashing red for the crossing road. This is also very common in California also.

I've never understood the practice of flashing red in this situation, even though I grew up with it.

THe closest intersection to my parent's old house that had one was at Poinsettia/Sunset in Hollywood.  Poinsettia is "broken" by Sunset and there are essentially two T-intersections both served by traffic lights.  A driveway from the Ralph's Supoermarket was directly across from the southern Poinsettia.  If you left the grocery, you'd see either solid red (when Sunset had green) or flashing red (when Poinsettia had green).  I guess it was to tell you that those leaving the grocery store who wanted to go south on Poinsettia had to yield to traffic on Poinsettia that was turning onto Sunset.

now, it's a traditional r-y-g light on all approaches, so left turns must yield to straight through traffic.

[Revive 755]

As depicted in this GSV image, there is a flashing yellow light instead of a green light at the corner of Haight and Octavia in SF.

http://goo.gl/maps/LdF22

That, and I believe traffic WB on Haight turning SB on Octavia (towards the freeway) has a green arrow and therefore right-of-way.

If it is intended to discourage anyone going straight across the intersection, flashing yellow arrows should be used instead of the flashing yellow balls. 

Also, if WB is supposed to have right-of-way over EB, and unless California has a different MUTCD and laws than elsewhere in the country, the given design is a good way to get someone from elsewhere in the country into an accident.  I would be wrongly assuming flashing yellow means Octavia has a flashing red and any WB left turner would supposed to yield to me if I was heading EB and turning right.

[citrus]

As depicted in this GSV image, there is a flashing yellow light instead of a green light at the corner of Haight and Octavia in SF.

http://goo.gl/maps/LdF22

That, and I believe traffic WB on Haight turning SB on Octavia (towards the freeway) has a green arrow and therefore right-of-way.

If it is intended to discourage anyone going straight across the intersection, flashing yellow arrows should be used instead of the flashing yellow balls. 

Also, if WB is supposed to have right-of-way over EB, and unless California has a different MUTCD and laws than elsewhere in the country, the given design is a good way to get someone from elsewhere in the country into an accident.  I would be wrongly assuming flashing yellow means Octavia has a flashing red and any WB left turner would supposed to yield to me if I was heading EB and turning right.

I was wrong - double checked street view, and WB Haight had no green arrow. By convention, it was generally accepted that EB traffic could turn onto the right lane of SB Octavia, and WB traffic got the left lane. (If you want accident-prone, just head a few blocks north on Octavia to Oak or Fell.)

Coincidentally, I went through that intersection (on a bus, no less!) on Sunday - signals are pretty much the same, except WB Haight now has a "LEFT TURN YIELD ON (green ball)" sign. Now WB left-turners must yield not just to pedestrians (as has always been the case) but also to oncoming bus traffic. Not sure how bikes fit in here. The bus lane worked as intended for me - got to pass a long line of cars on the EB block of Haight leading up to Octavia.

[Alps]

There's a flashing yellow along the Embarcadero facing a driveway between crosswalks. In that case, it's to warn cars exiting that they have to yield to pedestrians. However, a solid green ball should have the same connotation. There is no opposing cross traffic.

[mrsman]

There's a flashing yellow along the Embarcadero facing a driveway between crosswalks. In that case, it's to warn cars exiting that they have to yield to pedestrians. However, a solid green ball should have the same connotation. There is no opposing cross traffic.

Exactly.  A green ball should indicate that cross traffic has a red light and that left turners must yield to opposing traffic (if any) and all turning traffic must yield to pedestrians.  There is no need to come up with a different signal if you want to inform motorists of something that is very common.

In a split phasing situation, where opposing traffic has green at completely separate times, so that at all times you have a green, you also have a green left arrow.  But for this indication to work, pedestrians must not be allowed to cross against a green arrow.

Is there a way to indicate split phasing that a left turning car does not have to yield to opposing traffic (since they have a red) but must still yield to pedestrians?  The only times I've seen this in California were at intersections that have a green ball (no arrow) and a sign saying "3-way signal".  Usually, people turning left start in the middle of the intersection with some hesitation and then only proceed when they realize that opposing traffic has a red.  I believe this occurs at Palm/Beverly/Santa Monica in Beverly Hills (entering the intersection from Palm Dr), but I haven't been at that intersection in ages, so I don't know if they changed the timing.