Traffic signal

[6a]

I guess I just don't get why there is a need for both a ball and an arrow in these cases. Are these not all for turn only lanes? Why wouldn't an arrow along be enough?

[jakeroot]

Fife, Washington  ///  GSV is from Aug 2012 but the signal is still this way, at least as of 30 minutes ago.

Not quite sure why one right turn lane needs two arrows, but whatever.

If there was a sole arrow, and that light bulb burned out, one would never know when they have the right of way for the right turn.  It's always good to have 2 traffic lights serving the same purpose in case one has a malfunction of any sorts (including burned out bulbs).

I completely agree with the concept of emphasis, but this is a right turn. Worst case scenario, the traffic will stop on red, then follow through with the turn. If the arrow burned out, which isn't really a big deal because it would be replaced almost immediately, the turning traffic would just follow the left/straight signal, which would eventually display a green orb above a green left arrow. Wait, there's only one green orb ... these signals are really confusing me.

I guess I just don't get why there is a need for both a ball and an arrow in these cases. Are these not all for turn only lanes? Why wouldn't an arrow along be enough?

My guess is emphasis for the mainline (i.e. straight-through) traffic that it needs to stop.

[wisvishr0]

Fife, Washington  ///  GSV is from Aug 2012 but the signal is still this way, at least as of 30 minutes ago.

Not quite sure why one right turn lane needs two arrows, but whatever.

If there was a sole arrow, and that light bulb burned out, one would never know when they have the right of way for the right turn.  It's always good to have 2 traffic lights serving the same purpose in case one has a malfunction of any sorts (including burned out bulbs).

I completely agree with the concept of emphasis, but this is a right turn. Worst case scenario, the traffic will stop on red, then follow through with the turn. If the arrow burned out, which isn't really a big deal because it would be replaced almost immediately, the turning traffic would just follow the left/straight signal, which would eventually display a green orb above a green left arrow. Wait, there's only one green orb ... these signals are really confusing me.

I guess I just don't get why there is a need for both a ball and an arrow in these cases. Are these not all for turn only lanes? Why wouldn't an arrow along be enough?

My guess is emphasis for the mainline (i.e. straight-through) traffic that it needs to stop.

Yeah, most right turn doghouses don't have any redundancy measures here in Maryland (while left-turn doghouses do).

On a tangent, the redundant left turn "doghouses" actually become "dog towers" in many intersections in Maryland, as they enlarge and emphasize the left-turn indications.

[jeffandnicole]

Fife, Washington  ///  GSV is from Aug 2012 but the signal is still this way, at least as of 30 minutes ago.

Not quite sure why one right turn lane needs two arrows, but whatever.

If there was a sole arrow, and that light bulb burned out, one would never know when they have the right of way for the right turn.  It's always good to have 2 traffic lights serving the same purpose in case one has a malfunction of any sorts (including burned out bulbs).

I completely agree with the concept of emphasis, but this is a right turn. Worst case scenario, the traffic will stop on red, then follow through with the turn. If the arrow burned out, which isn't really a big deal because it would be replaced almost immediately, the turning traffic would just follow the left/straight signal, which would eventually display a green orb above a green left arrow. Wait, there's only one green orb ... these signals are really confusing me.

Don't be so sure about that.  There are people that will refuse to turn right on red no matter what.  And they wouldn't turn on a thru green ball because the right turn signal still stays red.  They will eventually go, I'm sure, after some irritating horn honking.

[Big John]

On a tangent, the redundant left turn "doghouses" actually become "dog towers" in many intersections in Maryland, as they enlarge and emphasize the left-turn indications.

MD decided that 8" lenses were appropriate for the near-side supplemental signal.  The arrows have to be on 12" lenses per MUTCD.

[jakeroot]

Fife, Washington  ///  GSV is from Aug 2012 but the signal is still this way, at least as of 30 minutes ago.

Not quite sure why one right turn lane needs two arrows, but whatever.

If there was a sole arrow, and that light bulb burned out, one would never know when they have the right of way for the right turn.  It's always good to have 2 traffic lights serving the same purpose in case one has a malfunction of any sorts (including burned out bulbs).

I completely agree with the concept of emphasis, but this is a right turn. Worst case scenario, the traffic will stop on red, then follow through with the turn. If the arrow burned out, which isn't really a big deal because it would be replaced almost immediately, the turning traffic would just follow the left/straight signal, which would eventually display a green orb above a green left arrow. Wait, there's only one green orb ... these signals are really confusing me.

Don't be so sure about that.  There are people that will refuse to turn right on red no matter what.  And they wouldn't turn on a thru green ball because the right turn signal still stays red.  They will eventually go, I'm sure, after some irritating horn honking.

The right turn signals are in line with the far left signal house. If the far left signal house displays a green arrow/green ball, the right two signals are green arrows. IF the arrows are burned out (both of them, god forbid), those two signals will simply be blank. Some of the more law-abiding citizens might opt to stop and then proceed as if following standard power-cut procedures, but most citizens probably won't notice them at all.

I'll go film the intersection later to give you an idea of what we are dealing with. I'll add a new post with a previous quote of yours to make sure you see it. Sound good?

[cl94]

On a tangent, the redundant left turn "doghouses" actually become "dog towers" in many intersections in Maryland, as they enlarge and emphasize the left-turn indications.

MD decided that 8" lenses were appropriate for the near-side supplemental signal.  The arrows have to be on 12" lenses per MUTCD.

NY Region 10 loves doing the "separate doghouse", except all lenses are 12". Never figured that one out.

[jakeroot]

On a tangent, the redundant left turn "doghouses" actually become "dog towers" in many intersections in Maryland, as they enlarge and emphasize the left-turn indications.

Those remind me of the Australian signal housings:



Granted, ours don't have the red arrow, but the concept is still fairly comparable.

That reminds me, why don't we use a red arrow that can just "disappear" when not needed (i.e. when there aren't pedestrians present)?

[M3019C LPS20]

Until the early 1970s, 1st generation neon pedestrian signals from Winko-Matic were still installed in New York City. They first appeared in the mid 1950s, and incandescent pedestrian signals took their place by the mid 1960s.

What were installed in later years appeared to be N.O.S. and were still dark olive green. Though all would eventually be repainted yellow.

[M3019C LPS20]

An early set-up from downtown Brooklyn in New York. 1950s. The first three-section traffic signals of the time were painted dark olive green, and a plumbizer arm was used to suspend a cluster of traffic signals. It would be in use for a short period of time until the traditional hanger would replace it sometime in the late 1950s.

[mrsman]

Fife, Washington  ///  GSV is from Aug 2012 but the signal is still this way, at least as of 30 minutes ago.

Not quite sure why one right turn lane needs two arrows, but whatever.

If there was a sole arrow, and that light bulb burned out, one would never know when they have the right of way for the right turn.  It's always good to have 2 traffic lights serving the same purpose in case one has a malfunction of any sorts (including burned out bulbs).

I completely agree with the concept of emphasis, but this is a right turn. Worst case scenario, the traffic will stop on red, then follow through with the turn. If the arrow burned out, which isn't really a big deal because it would be replaced almost immediately, the turning traffic would just follow the left/straight signal, which would eventually display a green orb above a green left arrow. Wait, there's only one green orb ... these signals are really confusing me.

Don't be so sure about that.  There are people that will refuse to turn right on red no matter what.  And they wouldn't turn on a thru green ball because the right turn signal still stays red.  They will eventually go, I'm sure, after some irritating horn honking.

You rarely see these in So. California.  Here is an example at the corner of Santa Monica and Wilshire in Beverly Hills:

http://goo.gl/maps/xC1ZJ


I'm not a fan of these types of signals either.  I beleive the MUTCD should be amended to require that on a three aspect signal head, all aspects should control  for the same direction and consequently no two aspects would ever be shown at the same time. 

So we should not see both a red light and a green arrow (left or right) on a three aspect signal turned on at the same time.  This should either be a doghouse, or a five aspect tower signal.

[PColumbus73]

I actually don't have a problem with the 3-section signal showing a red ball and green arrow simultaneously. I can understand a red ball with a green arrow on a doghouse, why is the 3-section red ball with a green arrow any different?

[mrsman]

I think the confusion is that at least from far away the signal appears to be showing conflicting directions.  In truth, there is no conflict, but it leads to the appearance.

[Revive 755]

^ But if the second head is for redundancy, IMHO it should be mounted on the support post for the mast arm, or a signal head should be provided on the near side of the intersection.

Supposedly, the signals at an intersection go into all-red flash if a movement has only one indication and that indication burns out.

You rarely see these in So. California.  Here is an example at the corner of Santa Monica and Wilshire in Beverly Hills:

http://goo.gl/maps/xC1ZJ


I'm not a fan of these types of signals either.  I beleive the MUTCD should be amended to require that on a three aspect signal head, all aspects should control  for the same direction and consequently no two aspects would ever be shown at the same time. 

So we should not see both a red light and a green arrow (left or right) on a three aspect signal turned on at the same time.  This should either be a doghouse, or a five aspect tower signal.

I think they are kind of prohibited already by parts of Section 4D of the MUTCD.  Assuming the green arrow indications are being used properly, the signal head design would fall under MUTCD Section 4D.23.  Paragraph 02, Item A-2 looks applicable:

2.  Steady CIRCULAR RED, steady right-turn YELLOW ARROW, and right-turn GREEN ARROW. Only one of three indications shall be displayed at any given time.

[mrsman]

^ But if the second head is for redundancy, IMHO it should be mounted on the support post for the mast arm, or a signal head should be provided on the near side of the intersection.

Supposedly, the signals at an intersection go into all-red flash if a movement has only one indication and that indication burns out.

You rarely see these in So. California.  Here is an example at the corner of Santa Monica and Wilshire in Beverly Hills:

http://goo.gl/maps/xC1ZJ


I'm not a fan of these types of signals either.  I beleive the MUTCD should be amended to require that on a three aspect signal head, all aspects should control  for the same direction and consequently no two aspects would ever be shown at the same time. 

So we should not see both a red light and a green arrow (left or right) on a three aspect signal turned on at the same time.  This should either be a doghouse, or a five aspect tower signal.

I think they are kind of prohibited already by parts of Section 4D of the MUTCD.  Assuming the green arrow indications are being used properly, the signal head design would fall under MUTCD Section 4D.23.  Paragraph 02, Item A-2 looks applicable:

2.  Steady CIRCULAR RED, steady right-turn YELLOW ARROW, and right-turn GREEN ARROW. Only one of three indications shall be displayed at any given time.

Yes, CIRCLE RED, YELLOW ARROW, GREEN ARROW is the perfect signal at an intersection where the only legal movement is a turn.  And in that case each signal phase would be exclusive and you would not see CIRCLE RED and GREEN ARROW at the same time.

[PColumbus73]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

[cl94]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

[jakeroot]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

As a driver, that signal would drive me crazy. If you are in the centre lane and the car in front of you decides to turn left, you're basically down to one straight lane, which is an unnecessary obstruction of traffic flow. Should just be two-left yield on green.

[cl94]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

As a driver, that signal would drive me crazy. If you are in the centre lane and the car in front of you decides to turn left, you're basically down to one straight lane, which is an unnecessary obstruction of traffic flow. Should just be two-left yield on green.

2 left yield on green is unheard of in New York. Typically, there isn't enough straight traffic at this location to require a second lane (it ends immediately beyond the signal), as it runs into a mountain pretty quickly. NY 254 ends at the signal and town maintenance takes over. Only needed for when school buses are going to/from the schools on the right. It used to be a single left and that was a nightmare during tourist season (the entire year). Typically, if the light is green, through traffic keeps to the right and both lanes are used as turn lanes. As the turn movement is by far the heaviest at this intersection (as in its AADT exceeds the AADT of the entire road west of this intersection by quite a bit) and the side road (SB offramp) is a minor movement (typically handled by Exit 20), there usually isn't much of a problem, with sensors keeping the turn movement going unless there is opposing traffic.

[Revive 755]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

Both of those run afoul of the MUTCD:

A protected only mode left-turn movement that does not begin and terminate at the same time as the adjacent through movement shall not be provided on an approach unless an exclusive left-turn lane exists.

A shared signal face shall not be used for protected only mode left turns unless the CIRCULAR GREEN and left-turn GREEN ARROW signal indications always begin and terminate together.

A protected only mode left-turn movement that does not begin and terminate at the same time as the adjacent through movement shall not be provided on an approach unless an exclusive left-turn lane exists.

A shared signal face shall not be used for protected only mode right turns unless the CIRCULAR GREEN and right-turn GREEN ARROW signal indications always begin and terminate together.

[cl94]

In the case with the example from California, the red w/ green arrow was for a right turn lane and a shared right/through lane. In that case, like the others, I think showing the red ball with the green arrow is just a matter of trying to stay consistent with other signals facing the same direction. If the 4-section signal (in the California example) had the red ball with a green arrow, and the 3-section had only the green arrow, it would look odd.

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

Both of those run afoul of the MUTCD:

A protected only mode left-turn movement that does not begin and terminate at the same time as the adjacent through movement shall not be provided on an approach unless an exclusive left-turn lane exists.

A shared signal face shall not be used for protected only mode left turns unless the CIRCULAR GREEN and left-turn GREEN ARROW signal indications always begin and terminate together.

A protected only mode left-turn movement that does not begin and terminate at the same time as the adjacent through movement shall not be provided on an approach unless an exclusive left-turn lane exists.

A shared signal face shall not be used for protected only mode right turns unless the CIRCULAR GREEN and right-turn GREEN ARROW signal indications always begin and terminate together.

When were these regulations put in? I say that because Region 1 does not typically go afoul of the MUTCD. That being said, the New York example should probably have the middle lane equipped with electronic lane use signage. The biggest issue is that there's a significant amount of traffic going from NY 254 to Saratoga or Albany when the second through lane is needed. What I would do is have a second dedicated turn lane at all times except 7-10 AM M-F and 7-11 AM Sundays. At these times, there would be a shared lane that follows the MUTCD. Opposing traffic is light enough to limit red times on NY 254. If the school wasn't right there, I'd toss in a loop ramp or flyover to get the turn movement out of the way, but that's just me.

[signalman]

New York, in a couple places, uses a dedicated turn signal, a doghouse, and a straight arrow in that order at double left turns where one lane has the option of turning or going straight. I-87 Exit 19 in Queensbury is an example. As the doghouse is all arrows, there is never a signal with an ambiguous movement. Differs from the standard approach to such an intersection in that the straight movement can occur without the turning movement.

This example reminds me of an example 1995hoo shared in DC.  I don't remember if it was earlier in this thread or another one.  IMO, it has bad idea written all over it.  In practice, locals may keep right to go straight.  But I can envision someone not familiar with the intersection wanting to go straight in the left lane, only to encounter someone waiting to turn left; where the left turning vehicle must wait for a green arrow.  The intersection should be restriped for either one through lane or widened to facilitate two dedicated left turn lanes. 

Someone else mentioned allowing a permissive double left turn.  I don't like that setup personally.  I think it makes someone in the left left turn lane more exposed to an accident due to the driver's lack of visibility.  Especially if the vehicle in the right left turn lane pulled past the stop bar a bit.

[jakeroot]

Someone else mentioned allowing a permissive double left turn.  I don't like that setup personally.  I think it makes someone in the left left turn lane more exposed to an accident due to the driver's lack of visibility.  Especially if the vehicle in the right left turn lane pulled past the stop bar a bit.

I've spent enough time in Edmonton to know that it works much better than you could ever imagine. And in almost all situations, both lines of traffic were well into the intersection waiting to turn. I can assure you that it feels like driving in another continent entirely.

Here's a picture of one of the intersections...there's not very many dual lefts in Edmonton, but I can count on one hand the number of protected-only signals I've ever seen. They are in fact so rare, the city installs "no left turn on red" signs (the symbolic Canadian version) to keep people from turning anyways:

[signalman]

^ I have to admit that sight lines look reasonable.  However, I'm still not sold on it being safe.  I've seen far too many impatient and stupid drivers out there.  While I'm all for weeding out the inept, I do feel bad for a driver going straight in the opposite direction who had the right of way and was guilty of nothing more than being in the wrong place at the wrong time.  Those are the drivers whom I'm looking to protect by making double lefts protected only.  I know one can argue the a left turner doesn't have to turn left during the permissive phase if they feel it's unsafe to do so.  However, if there isn't any protected phase, they may never feel it's safe to turn until after midnight.  I also know that the through vehicles going the opposite way should be in control of their vehicle at all times and be able to slow down to avoid a crash with someone turning left into their path.  However, I am in the group that speed doesn't kill, stupid does.  Unfortunately, we can't fix stupid.

[cl94]

^ I have to admit that sight lines look reasonable.  However, I'm still not sold on it being safe.  I've seen far too many impatient and stupid drivers out there.  While I'm all for weeding out the inept, I do feel bad for a driver going straight in the opposite direction who had the right of way and was guilty of nothing more than being in the wrong place at the wrong time.  Those are the drivers whom I'm looking to protect by making double lefts protected only.  I know one can argue the a left turner doesn't have to turn left during the permissive phase if they feel it's unsafe to do so.  However, if there isn't any protected phase, they may never feel it's safe to turn until after midnight.  I also know that the through vehicles going the opposite way should be in control of their vehicle at all times and be able to slow down to avoid a crash with someone turning left into their path.  However, I am in the group that speed doesn't kill, stupid does.  Unfortunately, we can't fix stupid.

I agree. But then again, how many double lefts are even in Canada? I can't remember any where I've been that weren't at a T intersection.