Traffic signal

[BamaZeus]

When I was a kid, I remember my father taking us into the city on a Sunday for a day-trip.  I think we went down to Grand Central on Park Avenue and did the loop-around there.  From there we waited for a fresh green light and went 100-something blocks with green lights on the timers at 35mph or so, until we exited to cross over into the Bronx.

I have no idea if they still have all the lights timed like that or not, but at least it existed circa 1985

[SignBridge]

NYC's signal timing goes all the way back to the 1960's when they changed from 2-color to 3-color signals. They had a legendary smart traffic engineer/Commissioner back then named Henry Barnes who started it all. And it's not just in Manhattan. I've had similar experiences driving the length of Queens Blvd. where I've gotten as many as 9 greens in a row before hitting a red light. Unfortunately the opposite is also true. If you hit it wrong, you end up stopping for a red light at every corner for a while. I remember my Dad commenting on that when the system began back in the 1960's.

BTW, I'm surprised to hear that NYC has no loop detectors. Roadman, are you sure about that? The entire city runs on timed signals? 

[agentsteel53]

When I was a kid, I remember my father taking us into the city on a Sunday for a day-trip.  I think we went down to Grand Central on Park Avenue and did the loop-around there.  From there we waited for a fresh green light and went 100-something blocks with green lights on the timers at 35mph or so, until we exited to cross over into the Bronx.

I have no idea if they still have all the lights timed like that or not, but at least it existed circa 1985

the last time I caught a green wave like that was in 2003 or so in Brooklyn.  at least 20-30 lights before we reached our intended destination.

other times I've driven in the city, I have not taken a single boulevard for a long distance, instead choosing to explore various side streets.  I do recall a run down Queens Blvd in 2008 for about 6-7 greens before it was my time to turn.

[iwishiwascanadian]

I remember going down Columbus Avenue for around 20 blocks without stopping, I never thought that I would experience a free-flow of traffic volume in Manhattan!

[SidS1045]

NYC's signal timing goes all the way back to the 1960's when they changed from 2-color to 3-color signals.

This conversion was still ongoing when I lived in Manhattan briefly in the 1970s.  (I used to work nights and the noise of the equipment woke me up out of a sound sleep promptly at 8AM.)  Supposedly there are still a few two-color signals left in some outlying areas of the city.

The way it was explained to me:  The city speed limit is 30mph unless otherwise posted.  The signals on the (approximately) north-south one-way avenues in Manhattan are set to sequence for a vehicle traveling at 28mph.  If you maintain that speed, you'll make every light.

[1995hoo]

NYC's signal timing goes all the way back to the 1960's when they changed from 2-color to 3-color signals.

This conversion was still ongoing when I lived in Manhattan briefly in the 1970s.  (I used to work nights and the noise of the equipment woke me up out of a sound sleep promptly at 8AM.)  Supposedly there are still a few two-color signals left in some outlying areas of the city.

....

I recall there being some two-color signals in Far Rockaway; the one that most readily comes to mind was where Seagirt Boulevard passes under the elevated A train structure and crosses Rockaway Freeway. My father's mother lived in the "Wavecrest Gardens" apartments at the intersection of Seagirt and Crest Road (though her unit overlooked Watjean Court and Fernside Place) and we used to take Beach Channel Drive to Seagirt Boulevard to go visit. I have not been there since she died (except in conjunction with the funeral Mass) and I see on Google Street View that there are now three-color signals at that particular intersection. I know they've been trying to make Rockaway Freeway less dangerous and I wonder if the traffic signal replacement might be part of that under the theory that the yellow light is needed for people blasting down Rockaway Freeway. I remember people always went WAY too fast on there.... (indeed after the first few trips when our grandmother moved out there, our father refused to use that road anymore and opted for Beach Channel Drive instead because it felt safer to him).

Funny thing is that for as long as I can remember (going back to the 1970s) the two traffic lights in Breezy Point were always three-color signals. From a practical standpoint I'd think that a private neighborhood would be one of the last ones to have the lights replaced, even if Rockaway Point Boulevard is a public road.



The guy who would probably know how many two-color signals are left, and where they are, is the webmaster of http://www.forgotten-ny.com.

[agentsteel53]

The way it was explained to me:  The city speed limit is 30mph unless otherwise posted.  The signals on the (approximately) north-south one-way avenues in Manhattan are set to sequence for a vehicle traveling at 28mph.  If you maintain that speed, you'll make every light.

in Klamath Falls, OR, the speed limit on the downtown main drag (business US-97/OR-39) is 25.  at each intersection, there is a sign that says "lights timed for 23 mph".

[1995hoo]

The way it was explained to me:  The city speed limit is 30mph unless otherwise posted.  The signals on the (approximately) north-south one-way avenues in Manhattan are set to sequence for a vehicle traveling at 28mph.  If you maintain that speed, you'll make every light.

in Klamath Falls, OR, the speed limit on the downtown main drag (business US-97/OR-39) is 25.  at each intersection, there is a sign that says "lights timed for 23 mph".

I've seen similar signs in many places, usually a white-on-green sign that says "Signals Set for [xy] MPH."

There's an unusual twist on the signals being set for a specific speed on Taylor Run Parkway in Alexandria, Virginia. That's a Street View link; the item of interest is the yellow sign to the right that says "Signals Turn Red When Speeding." The light in question can be seen if you move ahead a short distance; it's an annoying mid-block light that presumably they'd say is intended to ease pedestrian access to the park on the east side of the street but is almost certainly there to discourage cut-through traffic and speeding. First time I went through there I saw the yellow sign and said, "OK, whatever," and kept going at 30 mph in the 25-mph zone. Bam, the light turned red. Tried exceeding 25 two more times and the light turned every time. When I went 25 mph, it stayed green.

[agentsteel53]

30 in a 25 isn't even all that dangerous!

I looked at the road on Street View and it looks like the correct speed limit is either 25 or 30.  to enforce the speed limit like that is asinine.

[1995hoo]

30 in a 25 isn't even all that dangerous!

I looked at the road on Street View and it looks like the correct speed limit is either 25 or 30.  to enforce the speed limit like that is asinine.

It's 25. If you go back a short distance before the yellow sign to which I was referring, you'll see the Speed Limit 25 sign mounted on one of the telephone poles on the same side of the street.

This discussion is giving me the idea of driving down that street with my Valentine One turned on to try to find out what the signal uses to determine your speed–though I'd first have to make another pass through to ensure there's no cop around, as it's illegal to use a radar detector in Virginia.

[agentsteel53]

It's 25. If you go back a short distance before the yellow sign to which I was referring, you'll see the Speed Limit 25 sign mounted on one of the telephone poles on the same side of the street.

it is.  I meant that, from the perspective of what the road looks like, I wouldn't raise an eyebrow if it were signed 30.

[1995hoo]

It's 25. If you go back a short distance before the yellow sign to which I was referring, you'll see the Speed Limit 25 sign mounted on one of the telephone poles on the same side of the street.

it is.  I meant that, from the perspective of what the road looks like, I wouldn't raise an eyebrow if it were signed 30.

Ah, I misunderstood your meaning.

[agentsteel53]

indeed, I was driving some very similar residential streets today as part of avoiding a busy arterial, and the roads were almost all 30, with a few 35s where it opened up a bit, and a handful of 25s which were all (as far as I can tell) near schools and playgrounds.

[kphoger]

An example (three blocks from my house) of why I think all intersections should have post-mounted signals in addition to whatever overhead signals there are:


Is the light red or green?  Who knows!  Imagine sitting in a line of vehicles at a red light, and you're twelfth in line.  With that many cars having made it through a green light, there's a really good chance it'll turn red before you get there.  You might be able to see the red just before getting to the intersection (as the truck clears your line of vision), but the driver of the pickup in front of you won't see it until he's already made it to the stop line.

[roadman65]

An example (three blocks from my house) of why I think all intersections should have post-mounted signals in addition to whatever overhead signals there are:


Is the light red or green?  Who knows!  Imagine sitting in a line of vehicles at a red light, and you're twelfth in line.  With that many cars having made it through a green light, there's a really good chance it'll turn red before you get there.  You might be able to see the red just before getting to the intersection (as the truck clears your line of vision), but the driver of the pickup in front of you won't see it until he's already made it to the stop line.

That is what I experience in Florida.  Unfortunately, the MUTCD does allow this.  Only CA and NJ, and IL seem to post pole mounted signal heads.  In New Jersey, if there is no side mounted heads, usually the left side signal is placed on the backside of the opposing signal head over the opposite travel lane.

[SignBridge]

You can add Colorado and Wisconsin to that list also. And that photo certainly does make the case.

[deathtopumpkins]

Massachusetts also almost always posts both pole-mounted and overhead signals.

[SignBridge]

That was true on older Massachusetts signals. But I've noticed some new installations in Boston suburbs where they just have the typical 2 overhead signals on the standard tubular mast-arm.

[Big John]

Minnesota also places signals on the pole supporting the mast arm.

[iwishiwascanadian]

It's also done in Maryland, specifically on SHA maintained roads. It's not everywhere but it is quite common to see, especially throughout state routes in Baltimore County. 

[roadfro]

Only CA and NJ, and IL seem to post pole mounted signal heads.  In New Jersey, if there is no side mounted heads, usually the left side signal is placed on the backside of the opposing signal head over the opposite travel lane.

Nevada religiously uses far side post mount signal heads at all new signal installations for the through and left turn movements (this is also typical for most installations after the late 80s, at least in the Vegas area).

The Vegas area will also use an additional left turn signal head on the backside of opposing mast arm and a near side pole mount for through vehicles at wide intersections.

[deathtopumpkins]

That was true on older Massachusetts signals. But I've noticed some new installations in Boston suburbs where they just have the typical 2 overhead signals on the standard tubular mast-arm.

The difference there might be whether they're town- or state-posted signals. I've found all kinds of oddities among town-posted signals, but state seem to be fairly uniform.

Note though that by saying "fairly uniform", I mean "most of the time, but not all the time. I recognize that there are counterexamples but have noticed this as a general trend."

[kphoger]

Kansas is similarly usually good about this.  In fact, the next light to the west has post-mounted signals in addition to the overheads.  Usually just doesn't cut it for me, though, when it comes to stoplight visibility.

[kphoger]

Just last night, I saw a red light that was flickering quickly–not just pulsing in strength, but on-off-on-off-on-off, about as fast as you can say 'on-off-on-off-on-off'.  Kinda funny lookin'.
(Douglas & Woodlawn here in Wichita)

[Alps]

Just last night, I saw a red light that was flickering quickly–not just pulsing in strength, but on-off-on-off-on-off, about as fast as you can say 'on-off-on-off-on-off'.  Kinda funny lookin'.
(Douglas & Woodlawn here in Wichita)

Noticed the same with a green light yesterday. I wonder if that's a downside to LEDs or if it's just something about improper specs/installation.