Red left turn signals -- red ball or red arrow?

[jeffandnicole]

The Alabama DOT 1st Division has been retrofitting existing signals with red arrows, but they have not (yet) taken down the "LEFT TURN SIGNAL" signs.

I don't think that's all that unusual.  I see plenty of Left Turn/Right Turn arrows with the "Left Turn Signal"/"Right Turn Signal" sign.  Similiarly, I'll see "No Turn On Red" next to a Right Turn Arrow as well, which as well discussed, isn't needed in some states.

[Mdcastle]

Then you have the city of Chicago, which chooses to deliberately violate the MUTCD by having neither red arrow or red balls, instead having signs "left turn on green arrow only".

[codyg1985]

Then you have the city of Chicago, which chooses to deliberately violate the MUTCD by having neither red arrow or red balls, instead having signs "left turn on green arrow only".

So what would typically be a permissive signal (like a doghouse or tower) is treated like a protected-only left turn signal?

[Brandon]

Then you have the city of Chicago, which chooses to deliberately violate the MUTCD by having neither red arrow or red balls, instead having signs "left turn on green arrow only".

So what would typically be a permissive signal (like a doghouse or tower) is treated like a protected-only left turn signal?

You got it!  CDOT (Chicago Department of Transportation) likes to use five lamp towers and place the signs by them (which, by the way, is in violation of IDOT standards) instead of using a dedicated left turn signal with the signs.  CDOT has its own way of doing things which can be very different from the IDOT or ISTHA ways of doing things.

[Central Avenue]

The Alabama DOT 1st Division has been retrofitting existing signals with red arrows, but they have not (yet) taken down the "LEFT TURN SIGNAL" signs.

I don't think that's all that unusual.  I see plenty of Left Turn/Right Turn arrows with the "Left Turn Signal"/"Right Turn Signal" sign.  Similiarly, I'll see "No Turn On Red" next to a Right Turn Arrow as well, which as well discussed, isn't needed in some states.

It makes sense to me, at least in the case of a retrofitted arrow. People who are used to the red ball expect to see the LEFT TURN SIGNAL sign, and it doesn't cost anything to leave an existing sign in place for the remainder of its service life, so why not leave it there until people get used to the red arrow?

[kj3400]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

[kphoger]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

Granted.  But imagine someone who's used to seeing a red ball with a LEFT sign above it, approaching an intersection where the left arrow (no LEFT sign above it) has burnt out.  Does he go by the signals over the through lanes, or does he assume the indication for his movement might be different?

[Brandon]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

No time at all as it means the same thing.  In this state, Illinois, it still requires the use of "LEFT TURN SIGNAL" or "LEFT TURN ON GREEN ARROW ONLY" signs.

[kj3400]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

Granted.  But imagine someone who's used to seeing a red ball with a LEFT sign above it, approaching an intersection where the left arrow (no LEFT sign above it) has burnt out.  Does he go by the signals over the through lanes, or does he assume the indication for his movement might be different?

Fair point. But in that case, wouldn't there have been another signal with an arrow on it? I might be assuming things, since in Maryland, either there are two signals, or one signal with two red arrows.

[codyg1985]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

Granted.  But imagine someone who's used to seeing a red ball with a LEFT sign above it, approaching an intersection where the left arrow (no LEFT sign above it) has burnt out.  Does he go by the signals over the through lanes, or does he assume the indication for his movement might be different?

Fair point. But in that case, wouldn't there have been another signal with an arrow on it? I might be assuming things, since in Maryland, either there are two signals, or one signal with two red arrows.

That's not the case in a lot of places, such as Alabama, Mississippi, or Tennessee (outside of Memphis/Shelby County).

[mrsman]

Then you have the city of Chicago, which chooses to deliberately violate the MUTCD by having neither red arrow or red balls, instead having signs "left turn on green arrow only".

So what would typically be a permissive signal (like a doghouse or tower) is treated like a protected-only left turn signal?

You got it!  CDOT (Chicago Department of Transportation) likes to use five lamp towers and place the signs by them (which, by the way, is in violation of IDOT standards) instead of using a dedicated left turn signal with the signs.  CDOT has its own way of doing things which can be very different from the IDOT or ISTHA ways of doing things.

This discussion of Chicago practice reminds me of a situation that existed about 20 years ago in Los Angeles at the intersection of Beverly and La Cienega.  The original configuration had left turns from Beverly to La Cienega as a permissive left turn: doghouse on the mastarm and an 8-8-8-12-12 on the left pole.

There was then a project to restripe Beverly to allow for a dual left turn, and in California dual left turns are protective only.  They put in signs that said left turn on arrow only.  The doghouse operated in the style that you described above, but the signal on the left pole operated like a RA-YA-GA light, except that they still used the old hardware.  So 8 red-8 covered-8 covered-12 yellow arrow-12 green arrow.  It was very weird looking, but otherwise operated in the expected manner for protective lefts.

This was temporary though, about a month later, they changed the signal faces on and the mastarm and the left pole to the more common RA-YA-GA that we see at most protective only left turns.

[froggie]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

Granted.  But imagine someone who's used to seeing a red ball with a LEFT sign above it, approaching an intersection where the left arrow (no LEFT sign above it) has burnt out.  Does he go by the signals over the through lanes, or does he assume the indication for his movement might be different?

Fair point. But in that case, wouldn't there have been another signal with an arrow on it? I might be assuming things, since in Maryland, either there are two signals, or one signal with two red arrows.

That's not the case in a lot of places, such as Alabama, Mississippi, or Tennessee (outside of Memphis/Shelby County).

Indeed.  Numerous states where there is not a lot (or any) redundancy for left turn signals.  Maryland is the notable exception in that it seems to be statewide policy to have at least two (one on the far mast, one on the near mast).  Most states, when they have more than one, seem to only use it in urban areas or where there are dual left turn lanes.

[Brandon]

But how long does it take to get used to a red arrow? It's rather specific, as opposed to a red ball.

Granted.  But imagine someone who's used to seeing a red ball with a LEFT sign above it, approaching an intersection where the left arrow (no LEFT sign above it) has burnt out.  Does he go by the signals over the through lanes, or does he assume the indication for his movement might be different?

Fair point. But in that case, wouldn't there have been another signal with an arrow on it? I might be assuming things, since in Maryland, either there are two signals, or one signal with two red arrows.

That's not the case in a lot of places, such as Alabama, Mississippi, or Tennessee (outside of Memphis/Shelby County).

Indeed.  Numerous states where there is not a lot (or any) redundancy for left turn signals.  Maryland is the notable exception in that it seems to be statewide policy to have at least two (one on the far mast, one on the near mast).  Most states, when they have more than one, seem to only use it in urban areas or where there are dual left turn lanes.

Illinois is another of these states that require a minimum of two signals for the turning direction.  Quite commonly, one will see two five lamp towers (one on the mastarm, one post-mounted on the far left of the intersection) with one three lamp signal (also on the mastarm with one of the five lamp towers) for a smaller signalized intersection.  Illinois also requires the use of three signals per direction of travel, thus two towers and one three-lamp signal fit the bill quite nicely.  Even in areas where the FYA is used (IDOT District 4, Peoria), there are always two FYAs for the turning movement and two signals for the through and right movements (three lamp signals), accounting for four signals in a direction of travel.

[mrsman]

California also has at least 2 signal faces for left turns as well at each intersection.

[PColumbus73]

I prefer the double red arrow left turn signals that are all over South Carolina, I don't know if any other state uses this set up.

https://maps.google.com/maps?hl=en&ie=UTF8&ll=33.775404,-78.983131&spn=0.000966,0.001206&t=h&z=20&vpsrc=6&cbll=33.775339,-78.983206&panoid=xJEETdIFdCri8GOtSrRyHg&cbp=12,328.86,,0,0&ei=Rko6UpSwOKKGxgHwi4GwAw&pw=2

[MASTERNC]

I prefer the double red arrow left turn signals that are all over South Carolina, I don't know if any other state uses this set up.

https://maps.google.com/maps?hl=en&ie=UTF8&ll=33.775404,-78.983131&spn=0.000966,0.001206&t=h&z=20&vpsrc=6&cbll=33.775339,-78.983206&panoid=xJEETdIFdCri8GOtSrRyHg&cbp=12,328.86,,0,0&ei=Rko6UpSwOKKGxgHwi4GwAw&pw=2

Some counties in Maryland use double red arrows, but orient them vertically instead of horizontally.

[tradephoric]

Not a big fan of the double left turn arrows.  I would much rather see a pole mounted left turn signal head in addition to the overhead left turn signal head.  That way, if you are behind a large truck you can still look towards the pole mount signal to tell what indication is being displayed.

[getemngo]

Ahh yes, Michigan's rare diagonal span with flashing yellow arrow. (MDOT switched to box spans, as in 4 spanwires, for new installations several years before introducing the FYA). Feels like an anachronism. Oakland County, right?

One thing I've been wondering about: In states where the red arrows are just now being adopted (like Ohio and, apparently, Michigan), will existing red balls be replaced when their bulbs are replaced/converted to LED, or only when the intersection is reconfigured?

If it's the former, I'd expect to see a lot of signals with red arrows and redundant LEFT TURN SIGNAL signs (or, in Michigan's case, backlit LEFT boxes) cropping up over the next few years as the red balls are phased out.

It's worse than this. I've seen brand new installations, in both the Grand and Southwest regions, that have the "LEFT" banner above a red left arrow. Good thing these are always protected left turns, so you at least won't see flashing red arrows.

There's also an old style "LEFT" with red ball (again, protected, never flashing) that was installed just last month. I'm pretty sure MDOT contracted that one out, but... they're getting less consistent and making more mistakes now that there's less variety in acceptable signal types. I don't get that one.

I do like how common doghouse right turn signals are becoming in Michigan, though. 

[tradephoric]

Ahh yes, Michigan's rare diagonal span with flashing yellow arrow. (MDOT switched to box spans, as in 4 spanwires, for new installations several years before introducing the FYA). Feels like an anachronism. Oakland County, right?

Macomb County.  It's at 15 Mile & Garfield.

[Henry]

I prefer to see the red arrow. It makes the turn signal consistent with the green and yellow arrows.

[tradephoric]

Publication Number: FHWA-HRT-04-091
Date: August 2004

Application:  Using a 300-mm (12-inch) lens, in particular for the red indication, should improve visibility for the driver, and as such should reduce red light running and associated angle collisions.

Safety Performance:  As part of a safety improvement program conducted in Winston-Salem, NC, 300-mm (12-inch) signal lenses were installed on at least one approach at 58 intersections. The result was a 47-percent drop in right angle collisions and a 10-percent drop in total collisions.(135) A before-and-after study was undertaken to assess the effectiveness of larger (300 mm (12 inches)) and brighter signal head displays in British Columbia. Results from an EB analysis showed the frequency of total crashes was reduced by approximately 24 percent with the proposed signal displays. The results were found to be consistent with previous studies and laboratory tests that showed increased signal visibility results in shorter reaction times by drivers and leads to improved safety.(167)

A red ball has better visibility than a red arrow.  With a red ball, 100% of the 12" lens is illuminated, whereas with the red arrow maybe only 30-50% of the 12" lens is illuminated.  This is one of the simplest reasons why i prefer the red ball.

[Big John]

^^ A red ball should be used as the primary signals at the intersection.  The left-turn signal is a supplemental signal and is better to have a red arrow as not to be confused for a primary signal.  If the intersection allows left turns only, then it should be a green ball or arrow, yellow ball then red ball.

[Signal]

Charlottesville rarely even uses yellow arrows; most protected turn configurations are R-Y-GA.

The standard in Virginia is to have a red arrow for left turn signals, but I rarely see them.

[hotdogPi]

I often see yellow arrows but not red arrows.

[dfnva]

Charlottesville rarely even uses yellow arrows; most protected turn configurations are R-Y-GA.

The standard in Virginia is to have a red arrow for left turn signals, but I rarely see them.

Only in the mid- late 1980s did Virginia (VDOT) regularly start using yellow arrows for protected left signals.  This anachronistic practice is still done in rare cases, especially in independent cities which operate their own signals.  I didn't know it was still done in Charlottesville.   
Protected-permissive signals used yellow arrows before this time.