odd signal progression

[agentsteel53]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

am I just failing to think of something?

[jeffandnicole]

I've seen this in NJ's 4-head configured (basically, there's no red arrow, but the red ball counts as the same thing).

The only thing I can figure is some sort of limitation or programming in the light controller.  On the NJ state road intersections, generally the green arrow will stay lit on a red bulb until the thru-traffic light goes green.  In Gloucester County, NJ though, the progression is generally how you state it.  Slightly annoying!

[DaBigE]

The only thing I can think of is to prevent regular drivers from always expecting the green to follow. This way, they can vary the intersection timing in more ways without violating driver expectancy.

[Mr_Northside]

What kind of intersection?
Was there pedestrian crossing signals?  If there were, that would be my guess; They want traffic to stop while a conflicting pedestrian movement has the "Walk" signal. 
If there are no ped crossing signals at this intersection, I can't explain it. 

[jeffandnicole]

What kind of intersection?
Was there pedestrian crossing signals?  If there were, that would be my guess; They want traffic to stop while a conflicting pedestrian movement has the "Walk" signal. 
If there are no ped crossing signals at this intersection, I can't explain it. 

If it's what I'm thinking, the progression leaves an all red phase for only a second or two, not 20+ seconds which would be required for a ped crossing.

[NWI_Irish96]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

am I just failing to think of something?

There is an intersection like this right by my house.  It is a 4-way intersection where the primary traffic flow is between the south and west branches of the intersection.  The northbound traffic has a very long time where the light is green for both left and thru/right traffic.  During this time the eastbound traffic has a green arrow for traffic turning right.

This is followed by a very brief time where the light is green for northbound and southbound thru/right traffic, and the eastbound traffic will have a red arrow for turning right.  The next sequence in the light is a brief period where the eastbound and westbound traffic have a green light. 

So, for the eastbound traffic turning right, their sequence would be as you described above.  As an aside, this is a very dangerous intersection because the green right arrow lasts so long for the eastbound traffic that many cars assume they ALWAYS have that arrow and make right turns on red right in front of cars (namely me) that are going southbound thru the intersection and have to slam on the brakes to not hit them.

[catch22]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

am I just failing to think of something?

There are a few of these around here (western Wayne County, MI), most installed over the last couple of years.  I noticed that the right green-arrow, yellow-arrow, red-arrow sequence precisely matches the cross street's left-arrow sequence.  Could it be they just went for the cheap and use the same signal line for both?

[Brandon]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

am I just failing to think of something?

Not as many like this around here.  The various agencies (DOT, counties, municipalities) tend to use five lamp towers for a right turn signal like this with the following progression:

1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) green ball

[Revive 755]

For a right turn arrow around Chicagoland?  At least for Illinois portion of Chicagoland, excluding city of Chicago signals, most of the signals have the right turn after the through traffic since they overlap with the left turns on the cross street - the overlapping part has something to do with the signal controller.  This gives a sequence of:

1) Green ball
2) Yellow ball
3) Red ball
4) Red ball + Green right turn arrow (cross street has Green left turn arrow)
5) Red ball + Yellow right turn arrow (cross street has Yellow left turn arrow)
6) Red ball

For some of the older signals, the Green right turn arrow will appear on steps 2 and 3, but I'm told this is no longer allowed in the MUTCD.

[roadfro]

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

It's technically not necessary to pause the right turning traffic. However, it does make sense operationally. If there is a pedestrian phase that will accompany the circular green, it makes sense to bring turning traffic to a stop before initiating the walk phase (wherein right turning traffic would need to yield to pedestrians legally in the crosswalk before turning) so as to not transition directly from protected to "permitted" without a clearance interval.

Most FYAs typically follow this pattern as well, showing a brief red arrow before the flashing yellow arrow comes on (where protected phase proceeds permitted). It is a similar phasing principle.

Going briefly to a short red interval also helps reinforce that a protected phase does not always lead into a permitted phase.

For some of the older signals, the Green right turn arrow will appear on steps 2 and 3, but I'm told this is no longer allowed in the MUTCD.

I don't think that is expressly prohibited by the MUTCD, and could conceivably be a reasonable signal phase overlap as long as there are no conflicting phases.

[realjd]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

why is it necessary to pause the right-turning traffic, if they are going to get the green anyway?  I was approaching the light as this progression was taking place, and I came to a stop before my right turn - anticipating that I'd get traffic from my left, or ahead of me turning left, to yield to.  But this was not the case, so I was forced to make what I thought was an unnecessary stop.

am I just failing to think of something?

Is phase 3 long? I see this often where phase 2 corresponds to the cross street having a green left turn phase, followed by phase 3 corresponding to the cross streets all green phase.

[agentsteel53]

It's technically not necessary to pause the right turning traffic. However, it does make sense operationally. If there is a pedestrian phase that will accompany the circular green, it makes sense to bring turning traffic to a stop before initiating the walk phase (wherein right turning traffic would need to yield to pedestrians legally in the crosswalk before turning) so as to not transition directly from protected to "permitted" without a clearance interval.

Most FYAs typically follow this pattern as well, showing a brief red arrow before the flashing yellow arrow comes on (where protected phase proceeds permitted). It is a similar phasing principle.

Going briefly to a short red interval also helps reinforce that a protected phase does not always lead into a permitted phase.

got it.

in this case, there was no pedestrian phase, but I can see the controller implementing the short red briefly in all situations, regardless of whether or not the pedestrian phase was upcoming.

[thenetwork]

There are at least two intersections in Grand Junction, CO in which one set of left turn lanes gets a protected green arrow at both the beginning AND at the end of a cycle before the intersecting street gets their green. 

[roadman65]

On Lee Road in Winter Park, FL the eastbound left turn signal for I-4 EB Ramp gets a before and after left turn phase.

What is annoying that Orange County, FL changes the left turn phase depending on the time of day, and it can get confusing at times.  There are some that are not consistent, where at random the controller decides when the left turn phase should be as some lights where yesterday at the same time, same location, both days weekdays; where it was before the main phase was at that time post main phase.  I am guessing the controller is programed to make its own decisions in some applications based on data gathered from the detector loops.

[Kacie Jane]

I have seen this signal progression before - infrequently, but in many locations across the US.  does anyone have an explanation for why this is the case?

the progression is:
1) red ball, green right turn arrow
2) red ball, yellow right turn arrow
3) red ball, red right turn arrow
4) green ball

I think roadfro nailed the answer to this question.  However, that doesn't apply to a similar situation where I live: Samish Way & Lincoln Street. (If you can't make it out, even panning forward, there are three lanes: left only, straight only, and right only.  And there are two signal heads, each with four aspects, the left with a left arrow under the three balls, and the right with a right arrow.)

This morning, I approached from the north on Lincoln Street just as the light was turning red.  I believe oncoming traffic had a green at the time as well, so it was a permissive left, and the progression was as you might expect:

1) green balls, green right arrow
2) yellow balls, yellow right arrow
3) red balls (arrow unlit)

But as in Jake's example, #3 lasted only a second or two.  The next phase was protected lefts for cross traffic (coming from the east it's called Elwood Av, from the west, it's Samish Way).  So once those left turns got green arrows, so did the right turn from Lincoln onto Samish that had just turned red!  (This was the maneuver I was making, so I had to slow as I approached the intersection -- not knowing for certain what the next phase was even though I drive through the intersection almost daily -- but did not stop as the arrow turned green again well before I got to the stop line.)

Any logical explanation for this one?

To clarify:
1) green balls, green right arrow
2) yellow balls, yellow right arrow
3) red balls (arrow unlit) -- couple of seconds at most
4) red balls, green right arrow

[roadfro]

But as in Jake's example, #3 lasted only a second or two.  The next phase was protected lefts for cross traffic (coming from the east it's called Elwood Av, from the west, it's Samish Way).  So once those left turns got green arrows, so did the right turn from Lincoln onto Samish that had just turned red!  (This was the maneuver I was making, so I had to slow as I approached the intersection -- not knowing for certain what the next phase was even though I drive through the intersection almost daily -- but did not stop as the arrow turned green again well before I got to the stop line.)

Any logical explanation for this one?

To clarify:
1) green balls, green right arrow
2) yellow balls, yellow right arrow
3) red balls (arrow unlit) -- couple of seconds at most
4) red balls, green right arrow

As I'm understanding it, you're describing a signal head with standard circular red/yellow/green sections and a bi-modal green/yellow arrow underneath. If I recall correctly, such arrangements aren't exactly a common standard (I don't think it appears in the MUTCD).

Similar to the previous situation, this could be phased to overlap the southbound through with the eastbound/westbound turns. It could be a limitation in the signal controller with the overlap, but might also be related to the signal head itself and how that operates with the controller.