Traffic signal

[mrsman]

So then the final choice is to have what is presented above, protected only left in the option lane.  These are usually lagging lefts.

My example was a leading left if that changes anything.

It would make it worse for straight drivers in the option lane, since they know that if a left turner is ahead, there is no way that they are going to go until the next full signal cycle.

This type of signalization is never a great option, but it may be the only feasible option because widening the street is impractical and both straight and left need two lanes to handle demand.

[jakeroot]

One reasonable way to improve the intersection (Mexico at Jungermann, St Charles, MO) is a dynamic lane-use sign. The middle lane is either straight or left depending on the time of day. There would be four signals: one far left turn signal, an overhead left turn signal, and overhead through signal, and a right-side through signal.

During the straight-only time of day, you could even set the left turn to use permissive phasing. Then protected-only during the double-left time of day. During overnight hours, you might even be able to experiment with a permissive double left.

If the option lane is a must-keep, I would also advise lagging phasing. This would reduce the number of drivers trying to make sudden lane changes to pass a waiting vehicle, and might improve upon the possibly-risky setup they have here.

[SkyPesos]

I looked at Hong Kong's traffic signals on GSV for the past few minutes, and combined with what I saw in person on various trips there, found ZERO overhead traffic signals. I'm not sure if that's a good thing or not with having side signals only, though it looks like that it's possible to miss a signal, combined with all the buildings around in a city like HK. On the flipside, there's no overhead clutter.

[SkyPesos]

One reasonable way to improve the intersection (Mexico at Jungermann, St Charles, MO) is a dynamic lane-use sign. The middle lane is either straight or left depending on the time of day. There would be four signals: one far left turn signal, an overhead left turn signal, and overhead through signal, and a right-side through signal.

During the straight-only time of day, you could even set the left turn to use permissive phasing. Then protected-only during the double-left time of day. During overnight hours, you might even be able to experiment with a permissive double left.

If the option lane is a must-keep, I would also advise lagging phasing. This would reduce the number of drivers trying to make sudden lane changes to pass a waiting vehicle, and might improve upon the possibly-risky setup they have here.

It got improved by widening the road to allow for 2 separate left turn and straight lanes each already, though what you have seem like a good solution if the option lane was still there. Another option I could think of is to have separate phases for each direction on Mexico Rd with lights for all directions green at the same time. This is done at the Muegge Rd and Mexico Rd intersection just to the east already, which also have a option left/straight lane.

[kphoger]

For what it's worth, my Gainesville example had second-lane left turns added as an option.  The middle lane used to be straight-only.

[Mr Kite]

I looked at Hong Kong's traffic signals on GSV for the past few minutes, and combined with what I saw in person on various trips there, found ZERO overhead traffic signals. I'm not sure if that's a good thing or not with having side signals only, though it looks like that it's possible to miss a signal, combined with all the buildings around in a city like HK. On the flipside, there's no overhead clutter.

Hong Kong follows UK practice and so mast arms are fairly uncommon. There are a few examples though. Here, for example...

Nathan Rd
https://maps.app.goo.gl/LxaVbu8SHF4i7MRg6

[roadman65]

I see San Francisco is installing straight mast arms along Van Ness Avenue instead of usual California curved arms as part of that busway project. 

[jakeroot]

I looked at Hong Kong's traffic signals on GSV for the past few minutes, and combined with what I saw in person on various trips there, found ZERO overhead traffic signals. I'm not sure if that's a good thing or not with having side signals only, though it looks like that it's possible to miss a signal, combined with all the buildings around in a city like HK. On the flipside, there's no overhead clutter.

Hong Kong follows UK practice and so mast arms are fairly uncommon. There are a few examples though. Here, for example...

Nathan Rd
https://maps.app.goo.gl/LxaVbu8SHF4i7MRg6

I would also like to extend on the comment and highlight that mainland China is arguably worse in providing only overhead signals. Hong Kong-style has several post mounted signals at several different locations to the point where at least one is usually visible. Tall trucks and buses easily block the overhead signals on the mainland, as they do in many US states as well.

Ultimately, the best practice is likely that Nathan Rd example above: several signals at various corners of the intersection, and at least one overhead signal.

[SkyPesos]

I looked at Hong Kong's traffic signals on GSV for the past few minutes, and combined with what I saw in person on various trips there, found ZERO overhead traffic signals. I'm not sure if that's a good thing or not with having side signals only, though it looks like that it's possible to miss a signal, combined with all the buildings around in a city like HK. On the flipside, there's no overhead clutter.

Hong Kong follows UK practice and so mast arms are fairly uncommon. There are a few examples though. Here, for example...

Nathan Rd
https://maps.app.goo.gl/LxaVbu8SHF4i7MRg6

I would also like to extend on the comment and highlight that mainland China is arguably worse in providing only overhead signals. Hong Kong-style has several post mounted signals at several different locations to the point where at least one is usually visible. Tall trucks and buses easily block the overhead signals on the mainland, as they do in many US states as well.

Ultimately, the best practice is likely that Nathan Rd example above: several signals at various corners of the intersection, and at least one overhead signal.

That's an issue in a lot of US states that uses span wire signals too. Like here in Ohio, side signals are rare, especially in span wire installations.

And for China, although most cities don't do post mounted signals, something I'll give credit to Fuzhou for is installing traffic signals on the back side of mast arms, so at least there's a second traffic signal for each direction in case the one in the front gets blocked by tall vehicles.

[Mr Kite]

I would also like to extend on the comment and highlight that mainland China is arguably worse in providing only overhead signals. Hong Kong-style has several post mounted signals at several different locations to the point where at least one is usually visible. Tall trucks and buses easily block the overhead signals on the mainland, as they do in many US states as well.

Ultimately, the best practice is likely that Nathan Rd example above: several signals at various corners of the intersection, and at least one overhead signal.

I would say that California comes pretty close to best practice when there's a signal at the stop line. Sacramento is one municipality which always puts a signal at the line. Basically, a signal at the line, one on each far corner and one overhead on the far side.

[SignBridge]

I agree with Mr Kite. California's standard signal practices are the best. A reasonable combination of side-post mounts and overheads makes for good signal visibility all around.  I too like the practice of having a near-right corner supplemental head.

[Big John]

I agree with Mr Kite. California's standard signal practices are the best. A reasonable combination of side-post mounts and overheads makes for good signal visibility all around.  I too like the practice of having a near-right corner supplemental head.

Almost all Wisconsin's signals have those too.

[SignBridge]

Big John, I know that was standard on Wisconsin's older signals. Is it still their standard in new installations?

[Big John]

Big John, I know that was standard on Wisconsin's older signals. Is it still their standard in new installations?

Newer installations have more overhead signals, but they mostly have the supplemental signals including the near right (except for Eau Claire).

[SkyPesos]

With side mount signals in other Asian countries, it's something that Japan lacks too. Signal visibility isn't the best here imo (side question, any reason why Japan crams all lane movements onto one traffic signal, instead of using multiple?)
Taiwan have a similar issue as Japan, though they place the front overhead over the lanes that need them, instead of the opposite side unlike my Fuzhou example above and Japan. Also, is this one a protected or permissive left turn?
I think Singapore have the best signal layout of the Asian countries I've been too, with qualities Jakeroot described above. No overhead in this SPUI interchange though.

[roadman65]

https://www.flickr.com/photos/54480415@N08/51314006384/in/photostream
What is the X for in front of the future signal head lenses?

[jakeroot]

https://www.flickr.com/photos/54480415@N08/51314006384/in/photostream
What is the X for in front of the future signal head lenses?

It's just to indicate that it's not in service. It's an extra step above bagging the signals, which from a distance can sometimes make the signals appear as though they've just lost power. Only until you're close can you see the bags.

[tolbs17]

https://www.flickr.com/photos/54480415@N08/51314006384/in/photostream
What is the X for in front of the future signal head lenses?

It's just to indicate that it's not in service. It's an extra step above bagging the signals, which from a distance can sometimes make the signals appear as though they've just lost power. Only until you're close can you see the bags.

Never seen those here. I see the signals wrapped up normally or the pedestrian one saying "OUT OF SERVICE".

[jakeroot]

https://www.flickr.com/photos/54480415@N08/51314006384/in/photostream
What is the X for in front of the future signal head lenses?

It's just to indicate that it's not in service. It's an extra step above bagging the signals, which from a distance can sometimes make the signals appear as though they've just lost power. Only until you're close can you see the bags.

Never seen those here. I see the signals wrapped up normally or the pedestrian one saying "OUT OF SERVICE".

As I stated, it's an extra step. I've only seen it in California. Pretty much everywhere either gift wraps each signal face, or the entire signal head. The "X" design seems unique to California.

[roadman65]

I like the little two sections for transit vehicles here that not only California does but other cities in other states.



https://live.staticflickr.com/65535/51316663168_2fa6f82280_k.jpg

[SkyPesos]

Found a 4-section "green ball" protected-permissive signal in KC (check other views for the green ball). Not sure how common this is, as I've only seen doghouses (or 5-sections if placed on a vertical pole) in Missouri before. Also, which section would the yellow arrow use?

[Big John]

Found a 4-section "green ball" protected-permissive signal in KC (check other views for the green ball). Not sure how common this is, as I've only seen doghouses (or 5-sections if placed on a vertical pole) in Missouri before. Also, which section would the yellow arrow use?

Could it be a bi-modal arrow?

[Mr Kite]

It doesn't seem to be. Moving about on Streetview shows the arrow turned off during the main green. The arrow shows during the red in a "back-to-back" left turn stage with the opposite flow. How it terminates the protected mode is not clear.

[Mr Kite]

What's this all about?..

1 N Providence Rd
https://maps.app.goo.gl/s59AJSnjsPTY3NZ97

[Big John]

What's this all about?..

1 N Providence Rd
https://maps.app.goo.gl/s59AJSnjsPTY3NZ97

Or this similar signal in De Pere WI: https://goo.gl/maps/y6csZwTD26Z3Ucem9