Why did doghouses take so long to gain popularity

[traffic light guy]

Most of the signals that provide an exclusive phase for right turning (or left turning one-way to one-way, functionally the same thing) do so as lagging green arrows.  I believe the thinking is that pedestrians are liable to jaywalk and start crossing when they see a break in cross traffic.  They are more liable to jaywalk before the walk phase then keep walking right at the end.

So that's why most right turn signals are lagging yellow arrows.

[jakeroot]

The vast majority of one-way to one-way protected turns are lagging to better avoid conflict with jaywalkers.

This situation, at any rate, still strikes me as unusual given that most municipalities (outside of a few select areas) generally lead their turns, no matter which direction. It just seems to be the case that protected turns over crosswalks from one-way to one-way are almost always lagging. I can understand the jaywalking argument (although I hate that term, especially being someone who does it all the time to the chagrin of no one), but it seems that you could have the same issue at regular intersections. The left green arrow comes up, the car starts to turn, but has to proceed slowly because of someone who started crossing prematurely. I've seen a lot of municipalities around me address this issue by beginning a left turn phase with flashing yellow arrows instead, with the green arrow either at the end or not at all.

But in reality they are very different situations.

The standard left turn from a two-way street, the leading left is predominant.  Leading lefts are generally preferred since they can always be designed without worrying about the yellow trap problem.  This is true when only one side leads, both sides lead, both sides lead but one side has a heavier left turn load, etc.  it is very versatile.

Even though it is more rare, I prefer the lagging lefts, since they seem more efficient with respect to straight moving traffic.  If the traffic load is moderate, and there are good sensors, it is possible that a permissive left can be made during the green orb phase.  It would render the lagging left unnecessary and there won't even be a separate phase for it.  It improves the general signal operation.  For this reason it is preferred in situations where yellow trap is avoided (in situations where the opposing left is prohibited).  It is also useful (assuming yellow trap is avoided) in situations where there is an option lane present.  The lagging left will clear the traffic, where left turners have been blocking the intersection.  But given the problems with yellow trap, it is not used as often as leading lefts.

But the criteria for choosing a leading left in a two-way street is irrelevant for choosing a lagging signal for right turns or one-way to one-way left turns.  Right turns at a regular intersection will largely be dependant on the corresponding left turn and be lit during that period.  But if the right turn light were independent, and the sole reason for providing the right turn arrow is to have dedicated turning time in a heavy pedestrian area, then the criteria is based on how the turning traffic interacts with the pedestrian.

I declare that jaywalking is likely more common in areas with one-way street networks.  The pedestrian will likely look in the direction of the traffic he is crossing, determine that there is no cars and simply cross.  There are fewer turning conflicts in one way networks, plus many are in downtown areas with heavier pedestrian presence.  As it was determined that jaywalking is more common when a pedestrian gets to a corner, sees his light is red, watches cross traffic and crosses when there is a break in traffic even if his light is still red.  We do not want to put a protected arrow at this point in time, because it will be unexpected by the pedestrian*.  It is better at the end of the signal phase, where the pedestrian sees a FDW and runs knowing that his time is up and some conflicting traffic (usually cross traffic, but in this specific case right turning traffic) will likely start once the hand stops flashing.

So where the sole criteria of a protected arrow is the pedestrian interaction, the lagging signal is used.  But it will be leading to the extent that the turning signal interacts with another signal, like a corresponding (lagging) left turn or a bus queuing signal.

* You are correct that a leading left in a two-way intersection may also be a surprise to a jaywalking pedestrian, but the pedestrian interaction is simply not the criteria for choosing to use a left arrow in this instance.  The purpose is to provide protection against cross traffic, not pedestrians.  Also, jaywalking is less common as there are more moving parts to consider when crossing a busy two-way intersection.

I would absolutely agree that jaywalking is common along one-way streets, as there is simply less to look for. But consider how suburban or rural actuated signals may also affect pedestrians. In my area of Tacoma, the signals are largely timed, but there are some key intersections that use actuation with push-buttons. If you don't arrive at the correct time, you could end up waiting through at least a couple signal phases before you get your walk sign. In these situations, it's simply easier to jaywalk, irrespective of the road being two- or one-way. I doubt this is as common as jaywalking across a one-way street downtown, but I do think it's more common in areas without many one-way streets (where people are simply used to looking both ways all the time).

I do wonder, with the advent of the flashing yellow arrow, if the method or process of choosing intersection operation has changed. As you indicate, it was common for decades to reserve lagging green arrows for turns onto one-way streets, or when there are no oncoming left turns, or when there is an option lane, etc, etc. With flashing yellow arrows, we can almost compartmentalise each part of an intersection, something that wasn't really possible with 5-section left turn signals. For example, instead of looking at an intersection as being the crossroads of two major two-way roads, we can look at them as being the intersection of four one-way roads. You can look at the left turns that cross each of these roads, and the intersecting pedestrian or cycle movements, to determine appropriate signal operation. The old way of operating intersections was more about using a signal that controlled both through and turning traffic, but we can now look at very small, individual parts of the intersection to determine whether what happens there is deserving of leading or lagging protection, or any other number of things.

I know it sounds like I'm tripping on oxycontin, but I think there is some logic to this. Cities can look at intersections, and say "this particular crosswalk is a lot busier than the opposing crosswalk". Based on this, they can choose to lag the green arrows that intersect with that path to, as you say, reduce the potential for conflicts (particularly with drivers who "push" the yellow to the point where they end up entering on red, and cause a near-hit with someone whose foot is basically floating off the curb, waiting for that walk sign, and not really looking for cars).

I understand that we were talking about one-way roads, but I was thinking that there was some connection with all streets, in the sense that they all have pedestrians, and they all have turns that conflict with those pedestrians. And since fully protected turns are cool but not at all reasonable given a multitude of other factors*, I think it's important to dig deeper into intersection operation. In particular, how the FYA allows us to compartmentalise like never before.

* I once read a post on twitter where someone argued that allowing drivers to "yield on green" was the equivalent of giving two cross streets green lights at the same time. I get what he was trying to say, but it reminds me that some people cannot handle the concept of "giving way", so it's up to people like us to really be clever! And not piss them or drivers off.

[mrsman]

You are correct that the FYA concept does provide a lot of flexibility and could be looked at as a means for providing safer and more efficient traffic experiences.