Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Tom89t]

In California  there are traffic signals on the sides and overhead. In illnois, traffic signals are also overhead and on the sides. The California mutcd say that there must at least two traffic signals per phrase. In Illnois there must  be a least three traffic signals per direction.  I wish they had this practice in other states.   

[Brandon]

I've never seen a problem with Michigan's two signals per direction with one for left turns if there is a protected phase for the signal.  Nice and simple.

[kphoger]

On minor roads, I think two stoplights for through movement, and one extra if there's a left turn arrow, are sufficient; what are the chances that two of the same bulb will burn out at the same time?  On major thoroughfares, highways, etc., there should be at least two overhead and one ground-mounted, plus at least one overhead for any left turn lane and one ground-mounted on the left side.

[pianocello]

I like Iowa's general rule: one overhead light above each lane. The lights on the side don't seem to have much uniformity to them, but the newer ones seem to have one on each side.

[KEK Inc.]

I love California's traffic lighting.  I've witness people go through red lights stuck behind trucks all the time in Washington and Oregon.  Unless you're a bus length behind a tall truck, it's impossible to see the traffic signal unless there are lights on the side of the intersection.  

[roadfro]

The 2009 MUTCD requires two primary signal heads for the through movement (with at least one overhead), or for the major turning movement if a through movement does not exit. The 2003 MUTCD only required the major movement to have two signal heads. Additionally, current MUTCD guidance recommends two signal heads whenever there are two or more lanes for a particular movement. In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.


Nevada has pretty much followed the standard of at least two signal heads per phase for a while now. There are few installations without at least one overhead signal head, and the vast majority have a far-right pole mounted signal head for the through movement and a far-left pole mounted signal head for separate left turn phases.

In nearly all new Nevada installations, you'll find the following:
* One overhead signal head per lane for all phases
* One far-side pole-mounted signal head per phase (side-of-intersection position depends on movement and intersection geometry)
* For very wide intersections, a near-side pole-mounted signal head for the through movement and a near-side overhead-mounted signal head for the left turn movement.

[realjd]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

[Ian]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Delaware seems to like doing this.
http://maps.google.com/maps?q=millsboro,+de&hl=en&ll=38.546629,-75.243019&spn=0.019635,0.038581&sll=38.599164,-75.258408&sspn=0.313929,0.617294&vpsrc=6&hnear=Millsboro,+Sussex,+Delaware&t=h&z=15&layer=c&cbll=38.546629,-75.243019&panoid=_bvNLEEAvIXRXPYG1Xwx5w&cbp=12,289.01,,0,1

[Brandon]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

[Takumi]

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

I've seen that setup on occasion here in Virginia. I think I've even seen one that has just two left posts, one beside the left turn lane and one across the intersection from it.

[roadman65]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

New Jersey has two left turn signals regardless of the amount of lanes.  The through movements are spaced far enough apart that you can see around a truck if you are behind, unlike Florida where even if you are two car lengths behind a truck, you cannot see the signals at all.  On divided state highways, they have median mounted signal heads in New Jersey in addition to the overheads.  Some signals have 5 through signal heads, I have seen there!

[roadfro]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Nothing confusing about it. In typical Nevada fashion the "primary" (required) signal face and would be mounted overhead while the "secondary" is post-mounted on the far left.

Another way to achieve this, which is (was?) common in California at wide medians, is to have the "primary" face post-mounted in the median across from the left turn lane, and the "secondary" face post-mounted in the near-side median adjacent to the turn lane. I know of one such installation in the Vegas area--there used to be more, but they would often get hit...

[TXtoNJ]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

New Jersey has two left turn signals regardless of the amount of lanes.  The through movements are spaced far enough apart that you can see around a truck if you are behind, unlike Florida where even if you are two car lengths behind a truck, you cannot see the signals at all.  On divided state highways, they have median mounted signal heads in New Jersey in addition to the overheads.  Some signals have 5 through signal heads, I have seen there!

They've got to double up given the general lack of left turns in the state (I keed...)

[roadman65]

They've got to double up given the general lack of left turns in the state (I keed...)

They allow left turns in most places, but from the right lane!

--quote fixed: ms

[realjd]

In practice, two signal heads should always be provided for any movement regardless of the number of lanes, to provided redundancy in case one signal head fails for any reason.

Two signals for a single left turn lane? That would be confusing IMO.

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

I wasn't considering secondary, side mounted turn arrows. I was picturing two overhead turn arrow signals for a single left turn lane. I would find that confusing. A supplementary, side mounted left turn arrow is fine IMO.

[signalman]

^ I suppose I could see that if red balls were used, as opposed to red arrows.  But if two arrow signals are used overhead for one turn lane, I don't see what's so confusing.  Personally, I like the redundant turn signal, just incase one has a burnout or some other failure.  Delaware seems to do this extensively, and I always thought it was a good idea.

[SSOWorld]

They've got to double up given the general lack of left turns in the state (I keed...)

They allow left turns in most places, but from the right lane!

Recipe for disaster - oh wait, jughandles.

[hobsini2]

Not so.  IDOT always has two, even if they're five lamp towers.  One is usually mounted on a post on the far left corner, and the other is on the mast arm.

I've seen that setup on occasion here in Virginia. I think I've even seen one that has just two left posts, one beside the left turn lane and one across the intersection from it.

Wisconsin has that as a general rule if the road is a divided highway with one in the near median and one in the far median. This is generally the case with both the 5 light towers and the red arrow signals.

[bulkyorled]

In California was there possibly a rule change recently? I noticed in certain cities use to have 1 overhang light + 1 side light for wide intersections and certain cities around here (all in the same time frame mind you) changed out old poles and what not and replaced them with larger overhang arms with 2 overhang lights. Aside from just it being more visible, I thought it was weird that at least 5 cities near me all did it within the same year after having the old poles for so long

[roadfro]

^ Are these dual turn lane locations? Recommended practice in traffic signal design is to have one signal head above each lane for all movements.

[roadman65]

They've got to double up given the general lack of left turns in the state (I keed...)

They allow left turns in most places, but from the right lane!

Recipe for disaster - oh wait, jughandles.

That, in fact, it what the signs say before each individual jughandle:

ALL TURNS
  FROM
RIGHT LANE

[Crazy Volvo Guy]

In Illinois, the far-right signal head use is inconsistent at best.  Iowa seems to be a little better with the far-right signal heads, at least in Scott County; can't yet comment on other counties.

In California, I recall all signal installations having a far-right signal head.

New Hampshire is known to use a far-right signal head on occasion, though it's not very common.

Wisconsin seems to prefer near-right over far-right signals.  I personally prefer either a far-right, or both a near-right and a far-right, but not a near-right only.

[Super Mateo]

Here in Illinois, the far right signal head usually just appears in older installations, often those with the old style mast arm.  I haven't seen any new setups with a head on the far right. (By new, I mean after they started using black paint on the back of the visors.)  I like having a signal head on the far left as a back up for the left signal on the mast arm.  It's awful when I cross over to Indiana, where there's only one light for left turners, but I can barely see it because the sun is almost directly behind it.  Having that second light would help that problem.  I like how it's done here:  one signal on the far left, at least two on the mast arm, and maybe one on the near right.  Fives are all towers; there are no doghouses.  The only inline five I've seen in Indiana was on 45th at Calumet in Munster.