I'm hoping to get some more photos and videos up, but I wanted to write a bit about Japanese traffic signal operations.
First, I want to talk about the design. Japan primarily uses horizontal signals outside of two situations: (1) snowy areas, or (2) signals placed in tight spots for additional visibility. Otherwise, signals are always horizontal. Because Japan drives on the left, the horizontal signals are opposite from what you'd see in the right-hand traffic countries. So, red is on the far right, closest to the inside of the road, with green on the outside. Arrows are also used, and are placed below the main lenses at horizontal signals, and to the right at vertical signals. The arrows are always green, no yellow arrows to be found here. Most four way intersections will have a right-facing green arrow, some with left turn lanes also have a left turn filter signal. T intersections never have green arrows, the protected phase has oncoming traffic stop on red, but there is no indication of this to turning traffic; Japanese law does not seem to allow a green arrow and green orb to be lit simultaneously. The signals themselves are either grey or dark brown. There have been three design "ages": incandescent signals, then LED signals with visors, and (presently) LED signals without a visor. The non-visor signals are single units, rather than individual signal faces.
Next, I want to talk about operations. Japan is...not the most creative when it comes to signal phasing. The standard phasing is very simple: through traffic and pedestrians have green simultaneous, turning traffic yields; this is followed by a green arrow for right turning traffic. The right turn green arrows always come on at the same time, for both directions, no matter what. Most four-way intersections with turn lanes will have this operation, though some do not have any protected phase (example here with a double right turn). Three-way intersections, for traffic turning right off the top of the T, also typically get a protected phase, but as mentioned above, there is no green arrow; traffic has to deduce that it's their turn based on oncoming traffic having stopped. Regardless of the number of turn lanes, these operations described above are the same (double left turns, double right turns, everything is always a yield). Advanced left turns are exceedingly rare. I have only seen one, and it is shown with a green right, up, and left arrows and a red orb (example on my Flickr). Green phases of any kind always end with the yellow orb, even green arrows (so the main three-section signal will go from red to yellow if a green arrow phase is ending, kind of confusing if you only look for a split second).
Importantly: all traffic signals are timed. There are no actuated signals in Japan, that I've seen at least. I think they have time of day phasing, but that may be it. Pedestrian walk signals always activate with through traffic. Left on red is prohibited except on military installations.
I don't know if anyone here cares about Japan, or were curious. Hopefully this sums things up pretty well. Eventually I'll get some videos, since I know some of what I'm describing is pretty unusual.
Since you wrote a detailed traffic light article about Japan, I guess I'll also write a detailed traffic light article about Russia, because why not?
Regarding the design, most signals are vertically-arranged, although the standards permit horizontally-arranged signals. And indeed a few signals in my city are horizontal.
https://www.google.co.uk/maps/@55.988959,92.9070634,3a,42.6y,274.77h,99.22t/data=!3m6!1e1!3m4!1sUXhf9tuzWwFtJ9CJVp9BUw!2e0!7i13312!8i6656Regarding the operation, there are a few differences in the sequence from how it is in America.
Most traffic lights display "red+yellow" for 1 to 2 seconds before green, although the standards also permit "red straight to green" if the intersection is not coordinated with other intersections. The latter sequence is common in and around Moscow, and in a few cities such as Perm and Yekaterinburg.
Most traffic lights also flash green for 3 seconds before changing to yellow, although the standards merely recommend this. The yellow light is always 3 seconds long. Many intersections omit the "all-red" clearance period, and instead change at the same time. On that note, I've never seen any accidents caused by that.
These "red+yellow" and "flashing green" aspects are actually only recent additions; in the Soviet Union the traffic lights used to cycle "red->yellow->green->yellow".
Traffic lights often have "additional sections" on the side of the main green light, which are generally used to control turning movements, but some T-intersections may have straight additional sections.
https://www.google.com/maps/@56.0452431,92.7755264,3a,15y,343.09h,91.28t/data=!3m6!1e1!3m4!1sNVsoI4_chSf86JEey4w0Pw!2e0!7i16384!8i8192 The main green light will have an arrow outline on top, indicating the directions in which it applies, while the additional sections are full arrows.
If the traffic light is green, and the additional section is off, you must wait for the additional section to come on to proceed in it's direction. Some intersections display a red ring when the additional section is off to emphasise this. Most protected left turns are signalled in this way.
If the traffic light is red, and the additional section is on, you must give way to other road users before proceeding in it's direction. This is often used to permit "right turn on red".
There's also an experimental "yield to everyone before turning right" sign permitting right turns on red, that some cities have installed at intersections with low pedestrian volumes, in order to save costs on additional sections.
https://www.google.com/maps/@56.0629359,92.682687,3a,15y,66.29h,91.67t/data=!3m6!1e1!3m4!1szj4OOLwRWdT1PkBvXQTIeg!2e0!7i16384!8i8192Some traffic lights may use arrows instead of circles, this means that they only apply in the direction the arrows point. Generally this will be where you can't proceed in any other direction, other than in the direction of the arrows.
Historically, the traffic lights have been fixed-time, with traffic cops manually controlling the lights at busy intersections, for which they had special huts. However, the latter is not practiced anymore.
Today, most traffic lights are still fixed-time, with some intersections having different plans for different times of day, and different days.
To reduce delays, at night many traffic lights flash yellow in all directions, meaning that road users must obey the priority signs posted alongside the traffic lights, or yield to the right if there aren't any. However, this practice is slowly falling out of favour, as research at the Moscow Road Traffic Organisation Centre had shown that keeping the lights on at night reduced accidents by up to 38%. My city got rid of flashing yellow at night as early as 2013.
Countdown timers have been introduced in some cities (mine included) about 15 years ago, initially being a separate signal section on top of the red light. With the advent of LED traffic lights, the countdown timer is now commonly incorporated into the yellow light section, with the colour of the numbers either being white, or according to the colour of the traffic light. Countdown timers are also often incorporated into pedestrian signals. If the number is too big to be displayed, two dashes "--" will instead flash until the number gets down to 99. The countdown timers may also display two dashes at the end of the countdown, if for some reason the phase is continued.
Although fixed-time is the predominant form of control, things are moving, and in 2017, the first actuated traffic light was installed in the city of Zelenograd, at the intersection of Panfilovsky and Generala Alekseyeva avenues. Since then, all traffic lights in Zelenograd have been upgraded to be actuated. An interesting detail is that due to the Russian climate, with the roads needing to be resurfaced every year, the inductive loops are buried much deeper (15-17 m) than in most of the world (5-8 m).
This technology is locally known as a "smart intersection", and belongs to a company called "SpetsDorProject". On that note, they have a YouTube channel where they show off these traffic lights, and their installation, if anyone is interested. They also have a website with a cool map of all the "smart intersections" in Russia.
https://www.youtube.com/c/%D0%A1%D0%BF%D0%B5%D1%86%D0%94%D0%BE%D1%80%D0%9F%D1%80%D0%BE%D0%B5%D0%BA%D1%82/videoshttps://xn--e1aakgahhmflcmnd6jpe.xn--p1ai/For obvious reasons, actuated traffic lights do not display countdowns. However, some intersections run fixed-time plans at certain times of day (to allow coordination I suppose), and are actuated at other times of day. During these times, it instead displays "АУ", which stands for "Адаптивное Управление/Actuated Control". This is most common in St Petersburg and Belgorod, where this is often used for transit priority.
