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National Boards => General Highway Talk => Topic started by: kurumi on February 01, 2019, 11:52:16 AM

Title: If you "just miss" a green light, are you more likely to catch up later?
Post by: kurumi on February 01, 2019, 11:52:16 AM
The answer probably varies based on traffic light synchronization, distribution, etc.

Suppose there are 15 signals on your trip, and you "just miss" the first green by a few seconds.

Are you more likely to catch up at a future red as traffic is stopped, or would you be more likely to miss another one and fall further behind?
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: US71 on February 01, 2019, 11:59:14 AM
Quote from: kurumi on February 01, 2019, 11:52:16 AM
The answer probably varies based on traffic light synchronization, distribution, etc.

Suppose there are 15 signals on your trip, and you "just miss" the first green by a few seconds.

Are you more likely to catch up at a future red as traffic is stopped, or would you be more likely to miss another one and fall further behind?

Fort Smith says they are going to synchronize their signals this year, which will mean fewer redlights for drivers. Currently, it's a roll of the dice if you'll catch the succeeding greens or not. So overall it depends, as you said, on synchronization and distribution.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: kphoger on February 01, 2019, 01:39:50 PM
tradephoric would be the man to answer this question.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: Brandon on February 01, 2019, 01:53:45 PM
In Illinois, it's typically a crapshoot with the way they love actuated signals here.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 01, 2019, 03:32:44 PM
Along a perfect coordinated stretch of road (like Woodward Avenue in Detroit), if you "just miss" a green light it means you will never be able to catch up to that green wave you just lost. In light traffic conditions i like traveling near the end of the green wave because i can cruise a little over the speed limit and slowly catch up to the start of the green wave over several miles.  However, once you get closer to the start of the green wave, you really have to watch your speed and travel at the exact speed the signals are timed for (ie. usually the posted speed limit).

(https://i.imgur.com/bvb8y20.jpg)
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: johndoe on February 01, 2019, 03:36:34 PM
Of course it depends what those 15 signals look like: are the ones with most cross traffic on the ends of the corridor, in the middle, how far apart are they spaced, are they spaced equally, the speed limit, whether the engineer is trying to progress traffic in mainly one direction or both, or do any of the sidestreets require nice coordination too?  In real life there are compromises that have to be made (and too darn many people driving  :D)

In my experience it's a fun challenge and to an extent more "art" than "science" (how one engineer prefers things vs another).
I think you'd like to look up "time space diagrams"
http://ideasillustrated.com/blog/wp-content/uploads/2011/04/Traffic_Signal_Timing_Seq.jpg

Some more reading you may find interesting:
https://ops.fhwa.dot.gov/publications/fhwahop15038/app_a.htm
https://atspm.cflsmartroads.com/ATSPM/Images/ATSPM_Reporting_Details.pdf
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 01, 2019, 07:48:41 PM

Woodward Avenue is the birthplace of the modern traffic signal.  The first 4-way traffic signal tower in the world was installed at the corner of Woodward and Michigan Avenue in October, 1920.  By December 1920, additional signals were added along Woodward at Grand River, State, Fort, and Congress.  These additional signals were all connected to the main signal tower at Woodward and Michigan Avenue and manually controlled by a police officer sitting in the tower.  This was essentially the first inter-connected traffic signal corridor in the world. 

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Flarge.stanford.edu%2Fcourses%2F2011%2Fph240%2Fmiller1%2Fdocs%2Fmoyer%2Fimages%2Fmichigan-woodward.jpg&hash=a6bbf89d818d0461fbad95d98d420acaa798d204)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.kbrhorse.net%2Fsigpics2%2Fpotts_signal_intersection.jpg&hash=9412bfd61a00569dbc0f8bb64818ecfd323e2bab)

Mr. 'Trafficlight'
By Sheldon Moyer
Motor News, March 1947
http://large.stanford.edu/courses/2011/ph240/miller1/docs/moyer/

Nearly 100 years later they have definitely kept good signal progression along Woodward avenue.  Usually innovation is improved upon, but the first ever corridor with connected traffic signals still appears to be the best in regards to signal progression.  Drive for 40 miles, hit 124 consecutive green lights, and not get stopped.

https://www.youtube.com/watch?v=mb2R2fPB1nE
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 01, 2019, 07:59:17 PM
Quote from: tradephoric on February 01, 2019, 07:48:41 PM
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.kbrhorse.net%2Fsigpics2%2Fpotts_signal_intersection.jpg&hash=9412bfd61a00569dbc0f8bb64818ecfd323e2bab)

Little known fact....  that is my great, great grandfather in that picture :-D
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: hotdogPi on February 01, 2019, 08:04:51 PM
Quote from: tradephoric on February 01, 2019, 07:59:17 PM
Quote from: tradephoric on February 01, 2019, 07:48:41 PM
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.kbrhorse.net%2Fsigpics2%2Fpotts_signal_intersection.jpg&hash=9412bfd61a00569dbc0f8bb64818ecfd323e2bab)

Little known fact....  that is my great, great grandfather in that picture :-D

I must be missing the joke, unless what you're saying is actually true.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 01, 2019, 08:09:22 PM
^Just that I'm obviously into coordination and signals.  Guy's standing there holding up a stop/go paddle sign in 1920 along the first ever coordinated stretch of roadway.... kind of kindred spirits you could say.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: 1995hoo on February 02, 2019, 10:15:37 AM
Quote from: kurumi on February 01, 2019, 11:52:16 AM
The answer probably varies based on traffic light synchronization, distribution, etc.

Suppose there are 15 signals on your trip, and you "just miss" the first green by a few seconds.

Are you more likely to catch up at a future red as traffic is stopped, or would you be more likely to miss another one and fall further behind?

I think your first sentence answers the question, and another factor I'd add is that the time of day can make a difference if the light timing varies.  I can think of some lights in DC where at night (say, after hockey games) you can get through them right at the end of the cycle but during the day you can seemingly get through them only at the beginning of the cycle.

Of course, I think the biggest factor is other drivers. All it takes is one person in the way going the wrong speed and, if there is traffic in the other lanes preventing you from getting over, you get stuck.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jeffandnicole on February 02, 2019, 10:50:25 AM
I swear the elevator system in my building is hooked up to the traffic light outside. Cause everyone I leave and go outside, the direction I need to cross the street turns red!!
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 02, 2019, 10:57:38 AM
Signal progression along a corridor can change on a cycle by cycle basis, even as the underlying timing of each individual signal remains constant.  This is because there can be breaks in coordination along a corridor (due to geometry change, speed limit changes, traffic demands, etc.).  So while Woodward Avenue definitely has great signal progression, there is in fact only 2 or 3 cycles per hour where you could replicate that drive i posted above.... and to do so you need to be able to predict the Signal Phase and Time along the corridor (SPAT data).  Here's a quick and dirty graph showing SPAT data along Woodward Avenue.  If you leave the 'wrong cycle', you may get stopped as many as 5 times during that 40 mile stretch (still not bad).  But if you leave during one of those few perfect cycles, then you can cruise 40 miles without stopping.  But only if drivers are given this SPAT data will they know if their run is going to be good or not.

(https://i.imgur.com/m81pkSl.png)
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: Flint1979 on February 02, 2019, 11:02:50 AM
Quote from: tradephoric on February 02, 2019, 10:57:38 AM
Signal progression along a corridor can change on a cycle by cycle basis, even as the underlying timing of each individual signal remains constant.  This is because there can be breaks in coordination along a corridor (due to geometry change, speed limit changes, traffic demands, etc.).  So while Woodward Avenue definitely has great signal progression, there is in fact only 2 or 3 cycles per hour where you could replicate that drive i posted above.... and to do so you need to be able to predict the Signal Phase and Time along the corridor (SPAT data).  Here's a quick and dirty graph showing SPAT data along Woodward Avenue.  If you leave the 'wrong cycle', you may get stopped as many as 5 times during that 40 mile stretch (still not bad).  But if you leave during one of those few perfect cycles, then you can cruise 40 miles without stopping.  But only if drivers are given this SPAT data will they know if their run is going to be good or not.

(https://i.imgur.com/m81pkSl.png)
Well the only thing with that is that Woodward is not 40 miles long and the green wave on Woodward is between 9 Mile and Pontiac. Woodward is only about 25 miles long btw.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: Duke87 on February 03, 2019, 02:53:38 PM
I have observed in the past that if you stop at a red light heading southbound at this intersection (https://www.google.com/maps/@41.1256921,-73.5445007,3a,53.3y,172.75h,77.46t/data=!3m6!1e1!3m4!1soYfolYpMvgdg70pm_rOwFw!2e0!7i13312!8i6656) (CT 137/High Ridge Rd and Interlaken Rd), you are pretty much guaranteed to also stop at a red light at the following intersection (https://www.google.com/maps/@41.1231545,-73.5445818,3a,34.1y,188.02h,88.2t/data=!3m6!1e1!3m4!1sbxzkkBuzqFH0Dm7IEsdOXg!2e0!7i13312!8i6656) with Scofieldtown Rd (see? It even happened to the Street View car!).

I don't know why those lights are timed like this - maybe ConnDOT made no effort to deliberately coordinate them and it just worked out that way... or maybe they were supposed to be coordinated but the timing of one of the signals got skewed and it's never been corrected.

I do know the signal at Interlaken has only been there for about 20 years (it was a flasher prior to that); the signal at Scofieldtown is older.

Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: abefroman329 on February 03, 2019, 08:52:51 PM
Quote from: Brandon on February 01, 2019, 01:53:45 PM
In Illinois, it's typically a crapshoot with the way they love actuated signals here.
Not nearly as much as they love them in GA.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: RobbieL2415 on February 04, 2019, 04:28:55 PM
Usually it's a crapshoot what phase you're going to get next.  Every signal in my area has a pre-emption system and their cycles change depending on time of day.  The only timed-only signals left near here are in Hartford.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: hotdogPi on February 04, 2019, 04:34:12 PM
Here, they're all on sensors.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: RobbieL2415 on February 05, 2019, 12:07:20 AM
Quote from: 1 on February 04, 2019, 04:34:12 PM
Here, they're all on sensors.
Some towns are dodos birds and stick with timers.  Mainly towns with old installations.  Lots of setups on the Cape are timers only, for example.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: tradephoric on February 05, 2019, 11:09:37 AM
Quote from: RobbieL2415 on February 05, 2019, 12:07:20 AM
Quote from: 1 on February 04, 2019, 04:34:12 PM
Here, they're all on sensors.
Some towns are dodos birds and stick with timers.  Mainly towns with old installations.  Lots of setups on the Cape are timers only, for example.

There are no sensors along Woodward Avenue and it just runs fixed time.  You don't need state of the art adaptive signals if you have good geometry.  Much of Woodward Avenue runs 90 second cycles all day and night... a cycle that achieves near perfect dual progression along the corridor.  And it's a long enough cycle to maximize capacity during rush hour along the 2-phase signals yet short enough where people at 2AM aren't complaining about long reds.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: roadfro on February 06, 2019, 11:12:09 AM
Quote from: RobbieL2415 on February 04, 2019, 04:28:55 PM
Usually it's a crapshoot what phase you're going to get next.  Every signal in my area has a pre-emption system and their cycles change depending on time of day.  The only timed-only signals left near here are in Hartford.

Note that "preemption" is common on many traffic signals and has nothing to do with the signal timing or phasing. Preemption is what happens when a signal's normal operating cycle is overridden by some other event, such as changing to green for the direction of an emergency vehicle, or changing to all-way red flash due to a train coming on an adjacent railroad track.

You might be thinking of "detection" instead, which senses when vehicles are coming and (depending on the signal controller's programming) changes the signal phases to accommodate.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jakeroot on February 06, 2019, 04:17:13 PM
Your chances of making the next green light go down considerably (perhaps down to zero, as trade indicates). So, to answer the OP, not likely.

Even in non-timed environments, where signals use detection, it helps to drive as part of a pack, as a line of cars will keep a light green until an unknown maximum green time is reached. One of my pet-peeves is when drivers fall behind, creating a gap just large enough for the signal to "time"-out.

Because of this, as a driver, I always consider it my job to keep up with traffic, regardless of the limit.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: roadfro on February 09, 2019, 12:56:11 PM
Quote from: jakeroot on February 06, 2019, 04:17:13 PM
Even in non-timed environments, where signals use detection, it helps to drive as part of a pack, as a line of cars will keep a light green until an unknown maximum green time is reached. One of my pet-peeves is when drivers fall behind, creating a gap just large enough for the signal to "time"-out.

The signal controller setting for this is the "Passage Gap", which is a countdown timer tied to the upstream vehicle detectors–after the initial green time, the passage gap timer starts counting down, but resets every time a vehicle is detected upstream. If the passage gap timer reaches zero prior to the maximum green time, the signal turns yellow early–this is often referred to by signal engineers as "gap out" or "gapping out".
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jakeroot on February 09, 2019, 02:29:13 PM
Quote from: roadfro on February 09, 2019, 12:56:11 PM
Quote from: jakeroot on February 06, 2019, 04:17:13 PM
Even in non-timed environments, where signals use detection, it helps to drive as part of a pack, as a line of cars will keep a light green until an unknown maximum green time is reached. One of my pet-peeves is when drivers fall behind, creating a gap just large enough for the signal to "time"-out.

The signal controller setting for this is the "Passage Gap", which is a countdown timer tied to the upstream vehicle detectors–after the initial green time, the passage gap timer starts counting down, but resets every time a vehicle is detected upstream. If the passage gap timer reaches zero prior to the maximum green time, the signal turns yellow early–this is often referred to by signal engineers as "gap out" or "gapping out".

Thanks for the explanation. Never knew how that worked. The timer seems to be set around 1.5 to 2 seconds at most lights in my area (with the initial green time at most signals around 3 seconds).
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: roadfro on February 09, 2019, 05:26:29 PM
Quote from: jakeroot on February 09, 2019, 02:29:13 PM
Quote from: roadfro on February 09, 2019, 12:56:11 PM
Quote from: jakeroot on February 06, 2019, 04:17:13 PM
Even in non-timed environments, where signals use detection, it helps to drive as part of a pack, as a line of cars will keep a light green until an unknown maximum green time is reached. One of my pet-peeves is when drivers fall behind, creating a gap just large enough for the signal to "time"-out.

The signal controller setting for this is the "Passage Gap", which is a countdown timer tied to the upstream vehicle detectors–after the initial green time, the passage gap timer starts counting down, but resets every time a vehicle is detected upstream. If the passage gap timer reaches zero prior to the maximum green time, the signal turns yellow early–this is often referred to by signal engineers as "gap out" or "gapping out".

Thanks for the explanation. Never knew how that worked. The timer seems to be set around 1.5 to 2 seconds at most lights in my area (with the initial green time at most signals around 3 seconds).
It varies depending on upstream detector placement and assumed roadway speed/speed limit, but I believe 2 seconds is a pretty common value for passage gap.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jakeroot on February 09, 2019, 08:51:16 PM
Quote from: roadfro on February 09, 2019, 05:26:29 PM
Quote from: jakeroot on February 09, 2019, 02:29:13 PM
Quote from: roadfro on February 09, 2019, 12:56:11 PM
Quote from: jakeroot on February 06, 2019, 04:17:13 PM
Even in non-timed environments, where signals use detection, it helps to drive as part of a pack, as a line of cars will keep a light green until an unknown maximum green time is reached. One of my pet-peeves is when drivers fall behind, creating a gap just large enough for the signal to "time"-out.
The signal controller setting for this is the "Passage Gap", which is a countdown timer tied to the upstream vehicle detectors–after the initial green time, the passage gap timer starts counting down, but resets every time a vehicle is detected upstream. If the passage gap timer reaches zero prior to the maximum green time, the signal turns yellow early–this is often referred to by signal engineers as "gap out" or "gapping out".
Thanks for the explanation. Never knew how that worked. The timer seems to be set around 1.5 to 2 seconds at most lights in my area (with the initial green time at most signals around 3 seconds).
It varies depending on upstream detector placement and assumed roadway speed/speed limit, but I believe 2 seconds is a pretty common value for passage gap.

Which is odd to me, since I believe the WA driving manual suggests four-second following distances at 40 mph. Which is insane, of course, and ignored by everyone for being insane. But thank god for that, otherwise signals would be "gapping out" left and right.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: roadfro on February 12, 2019, 09:36:53 PM


Quote from: jakeroot on February 09, 2019, 08:51:16 PM
Quote from: roadfro on February 09, 2019, 05:26:29 PM
Quote from: jakeroot on February 09, 2019, 02:29:13 PM
Thanks for the explanation. Never knew how that worked. The timer seems to be set around 1.5 to 2 seconds at most lights in my area (with the initial green time at most signals around 3 seconds).
It varies depending on upstream detector placement and assumed roadway speed/speed limit, but I believe 2 seconds is a pretty common value for passage gap.

Which is odd to me, since I believe the WA driving manual suggests four-second following distances at 40 mph. Which is insane, of course, and ignored by everyone for being insane. But thank god for that, otherwise signals would be "gapping out" left and right.

The upstream detectors and passage gap timer are set independently of any assumed vehicle following distance. But I do seem to recall (I'd have to check old textbooks/notes from undergrad) that detectors are supposed to be placed and passage gap set such that a car passing at the 85th percentile speed/speed limit would be able to clear the stop line before the light turns yellow.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jakeroot on February 13, 2019, 12:46:56 AM
Quote from: roadfro on February 12, 2019, 09:36:53 PM
The upstream detectors and passage gap timer are set independently of any assumed vehicle following distance. But I do seem to recall (I'd have to check old textbooks/notes from undergrad) that detectors are supposed to be placed and passage gap set such that a car passing at the 85th percentile speed/speed limit would be able to clear the stop line before the light turns yellow.

I've always been bothered by those who insist on the exact posted limit. Now, I have a scientific reason for it to bother me.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: roadfro on February 13, 2019, 02:45:27 AM
Quote from: jakeroot on February 13, 2019, 12:46:56 AM
Quote from: roadfro on February 12, 2019, 09:36:53 PM
The upstream detectors and passage gap timer are set independently of any assumed vehicle following distance. But I do seem to recall (I'd have to check old textbooks/notes from undergrad) that detectors are supposed to be placed and passage gap set such that a car passing at the 85th percentile speed/speed limit would be able to clear the stop line before the light turns yellow.

I've always been bothered by those who insist on the exact posted limit. Now, I have a scientific reason for it to bother me.

I was incorrect. I think I was confusing the passage gap calculation with the dilemma zone calculation...

The formula for setting passage time takes the maximum allowable headway (following distance) and subtracts another term derived from detector+vehicle lengths over average approach speed (usually posted speed limit is used). Passage gap considers headways between vehicles to determine how long to extend the phase, so the placement of detectors is actually not a critical factor–stop line detectors can be (but are not commonly) used for this–but the detector placement and design still needs to be considered.

BTW: Several factors in traffic signal timing rely on 85th percentile speed or average approach speeds–more often than not, posted speed limits are substituted for this term in calculations, since it is a known value that does not require a speed study to determine a precise value.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: MikieTimT on February 14, 2019, 06:55:54 AM
Other than signals that are managed from a single cabinet over a few too-closely spaced intersections in Arkansas, I've not noticed that signals are timed from one to another period anymore.  It used to be before the advent of cameras/loops that some effort was made to time lights on a given major thoroughfare, but it seems like those days are long gone.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: jakeroot on February 15, 2019, 02:21:32 PM
Quote from: roadfro on February 13, 2019, 02:45:27 AM
BTW: Several factors in traffic signal timing rely on 85th percentile speed or average approach speeds–more often than not, posted speed limits are substituted for this term in calculations, since it is a known value that does not require a speed study to determine a precise value.

I see. I will partially retract my statement, though "keeping up" still seems like the easiest way to game the system. :D

Quote from: MikieTimT on February 14, 2019, 06:55:54 AM
Other than signals that are managed from a single cabinet over a few too-closely spaced intersections in Arkansas, I've not noticed that signals are timed from one to another period anymore.  It used to be before the advent of cameras/loops that some effort was made to time lights on a given major thoroughfare, but it seems like those days are long gone.

It seems to me that, especially in the 50s and 60s, before the wide use of things like protected left turns, signal programming was relatively simple. Each intersection likely had only two phases, and as there were no detection technology, every signal was timed. So they timed them appropriate for through progression, or as best they could assuming no other traffic. Now, with lots more traffic, signals for each movement, crosswalks (egad!), etc, more advanced technology has become necessary. What I see, now, in suburban areas, when lights are spaced around 10+ blocks apart, is for each to run independently, with the lights able to stay green when platoons are detected (using the aforementioned passage gap calculation). There's also lead/lag phasing, which can help TOD operation.

From what I've seen, these advanced signal technologies can handle heavy traffic really well, although they can be a bit maddening during lighter hours when they change, what seems like, every 7 seconds to account for each arriving car. Hell, they sometimes feel like four-way stops in the overnight hours.
Title: Re: If you "just miss" a green light, are you more likely to catch up later?
Post by: MikieTimT on February 17, 2019, 02:16:42 PM
Quote from: jakeroot on February 15, 2019, 02:21:32 PM
Quote from: roadfro on February 13, 2019, 02:45:27 AM
BTW: Several factors in traffic signal timing rely on 85th percentile speed or average approach speeds–more often than not, posted speed limits are substituted for this term in calculations, since it is a known value that does not require a speed study to determine a precise value.

I see. I will partially retract my statement, though "keeping up" still seems like the easiest way to game the system. :D

Quote from: MikieTimT on February 14, 2019, 06:55:54 AM
Other than signals that are managed from a single cabinet over a few too-closely spaced intersections in Arkansas, I've not noticed that signals are timed from one to another period anymore.  It used to be before the advent of cameras/loops that some effort was made to time lights on a given major thoroughfare, but it seems like those days are long gone.

It seems to me that, especially in the 50s and 60s, before the wide use of things like protected left turns, signal programming was relatively simple. Each intersection likely had only two phases, and as there were no detection technology, every signal was timed. So they timed them appropriate for through progression, or as best they could assuming no other traffic. Now, with lots more traffic, signals for each movement, crosswalks (egad!), etc, more advanced technology has become necessary. What I see, now, in suburban areas, when lights are spaced around 10+ blocks apart, is for each to run independently, with the lights able to stay green when platoons are detected (using the aforementioned passage gap calculation). There's also lead/lag phasing, which can help TOD operation.

From what I've seen, these advanced signal technologies can handle heavy traffic really well, although they can be a bit maddening during lighter hours when they change, what seems like, every 7 seconds to account for each arriving car. Hell, they sometimes feel like four-way stops in the overnight hours.

I remember back when I was a kid and we lived out in the boonies 40 miles south of Ft. Smith, AR.  My dad used to take my brother and I to Irish-Made donuts about 6AM on a Saturday to get some freshly made donuts.  The traffic lights on Towson Ave. all used to be flashing yellow on Towson and flashing red on the intersecting streets during nights and weekends.  Made so much more sense back then than the way they do things now.  There is almost always one road that has more traffic than the other road at an intersection that it would make sense to change over to flashing yellow during the lighter times.  Flow through the intersections would be better to allow one road to always have priority in those off times and essentially a flashing red stop light for the intersecting road.  I guarantee that on average those on the intersecting roads would still wait at the intersection less than the sensors can switch their light to green.  Essentially the way things are now, stoplights really do act as stoplights for everyone in lighter traffic.

That same stretch of road was timed on stoplights during their regularly functioning times where driving the speed limit would only catch one of the stoplights, but allow you through the rest of the intersections on green after you'd been held up once.  I can't say that progress has really been made with the changes in traffic light control over the last 2 decades.