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Old 12-18-2009, 03:37 AM
 
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The new 2009 Manual of Uniform Traffic Control Devices is now the standard. It was released Wednesday December 16, 2009. I already downloaded my copy (free, 27MB, pdf). Google MUTCD.

Some changes in the manual regarding traffic signals:

- No 8" signals except nearside posts, speeds 30 mph and below, or other special conditions
- Flashing yellow arrows 4-section face now the standard signal for protected/permissive left turn signals.
- Flashing yellow arrow means turn after yielding to opposing traffic.
- Flashing red arrow means turn after stop.
- Doghouse still allowed, but restricted to placement to the right of the lane line between left turn and thru lanes.
- Yellow trap must be eliminated or signed (as in 2003 edition, but no grace period).
- Dallas Phasing no longer allowed.
- No circular green allowed over or in line with the left turn lane.
- No circular red allowed on exclusive left turn signals. Must have red arrow.
- No turn after stop on red arrow unless sign permits or red arrow flashes.
- Right turn signals have circular red if turn on red allowed, steady red arrow if prohibited.
- Exclusively protected turn phasing not allowed if no exclusive turn lane exists, unless both phases simultaneous.
- Exclusive turn signal not allowed if no exclusive turn lane exists.
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Old 12-18-2009, 09:35 AM
Bo Bo won $500 in our forum's Most Engaging Poster Contest - Tenth Edition (Apr-May 2014). 

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Location: Ohio
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What do these items on your list mean?

Quote:
Originally Posted by Troubleshooter View Post
- Doghouse still allowed, but restricted to placement to the right of the lane line between left turn and thru lanes.
- Yellow trap must be eliminated or signed (as in 2003 edition, but no grace period).
- Dallas Phasing no longer allowed.
If the flashing yellow arrow caused people to be confused, the flashing red one will be even more confusing to those people! I do agree with the concept, though and I hope it gets used in more places.
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Old 12-21-2009, 01:52 AM
 
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Quote:
- Doghouse still allowed, but restricted to placement to the right of the lane line between left turn and thru lanes.

The 5-section 2-arrow shared thru and left turn cluster signal is commonly called a "doghouse" due to its shape. It is still allowed, as are the variants that are straight 5-section vertical or horizontal faces.

But there are two new rules that affect these faces:

1. A shared left turn and straight ahead face must be located either over the continuation of the leftmost thru lane, or over an extension of the lane line separating the leftmost thru lane from the left turn lane. It shall not be located to the left of this line.

2. No face containing any circular indication shall be located to the left of an extension of the lane line separating the leftmost thru lane from the left turn lane.


Quote:
- Yellow trap must be eliminated or signed (as in 2003 edition, but no grace period).

If permissive left turns are allowed, the permissive left turn must not be ended before the oncoming straight-ahead green is ended. Ending the permissive left turn before the oncoming green causes yellow trap. A driver turning left when this happens might turn across live traffic moving on the green, expecting the oncoming traffic to stop. Or if he doesn't turn, he might be trapped in the intersection with a red signal and live traffic crossing his path.

Quote:
- Dallas Phasing no longer allowed.

Dallas Phasing was developed before Flashing Yellow Arrows as a method to prevent yellow trap. It uses the doghouse or inline 5-section signal for an exclusive left turn signal. The circular green lights for a permissive turn when the oncoming circular green lights, and the other lenses behave with this in mind. But the circular green and yellow lenses must be visibility limited so the thru drivers can't see them.

This means that Dallas Phasing requires a rigid mounting for the signal face for Dallas Phasing. It can't be used with span wires or free swinging mounts. A mast arm or signal bridge must be used. And left-turning drivers were confused by seeing a circular green while the thru signals were red.

Now that Flashing Yellow Arrows have been shown to work much better than Dallas Phasing, the definition and requirements for using Dallas Phasing that were in the 2003 MUTCD were removed from the 2009 MUTCD. The new requirement that a circular green not be located over the left turn lane prevents the use of Dallas Phasing.
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Old 12-21-2009, 08:45 AM
Bo Bo won $500 in our forum's Most Engaging Poster Contest - Tenth Edition (Apr-May 2014). 

Over $104,000 in prizes has already been given out to active posters on our forum and additional contests are planned
 
Location: Ohio
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Thanks for the info. I spent some of the downtime during a summer internship many years ago reading traffic engineering books, and your descriptions remind me of that. It takes a bit of thought and recall, relating the descriptions to intersections like these to fully grasp it all, but it does make sense.
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Old 01-19-2010, 12:46 PM
 
Location: San Antonio
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Quote:
Originally Posted by Troubleshooter View Post
Dallas Phasing was developed before Flashing Yellow Arrows as a method to prevent yellow trap. It uses the doghouse or inline 5-section signal for an exclusive left turn signal. The circular green lights for a permissive turn when the oncoming circular green lights, and the other lenses behave with this in mind. But the circular green and yellow lenses must be visibility limited so the thru drivers can't see them.

This means that Dallas Phasing requires a rigid mounting for the signal face for Dallas Phasing. It can't be used with span wires or free swinging mounts. A mast arm or signal bridge must be used. And left-turning drivers were confused by seeing a circular green while the thru signals were red.

Now that Flashing Yellow Arrows have been shown to work much better than Dallas Phasing, the definition and requirements for using Dallas Phasing that were in the 2003 MUTCD were removed from the 2009 MUTCD. The new requirement that a circular green not be located over the left turn lane prevents the use of Dallas Phasing.
For anyone in San Antonio who wants to see Dallas Phasing in action, check out the intersection of Wurzbach and Floyd Curl in the Medical Center. All four approaches there use Dallas Phasing. The two Floyd Curl approaches at Medical also employ DP.
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Old 08-04-2010, 06:07 PM
 
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We have them in Ofallon Mo now....I have witnessed 5 close calls due to people thinking they can go on these....If it causes me to get hit there will be a lawsuit for sure!!!
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Old 08-05-2010, 06:22 PM
 
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Geez, I thought Dallas phasing meant I demateralize and reappear in Plano.
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Old 11-19-2010, 03:10 PM
 
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Update: Existing installations of Dallas Phasing are allowed to remain.
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Old 11-19-2010, 05:20 PM
Bo Bo won $500 in our forum's Most Engaging Poster Contest - Tenth Edition (Apr-May 2014). 

Over $104,000 in prizes has already been given out to active posters on our forum and additional contests are planned
 
Location: Ohio
17,105 posts, read 36,520,391 times
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Quote:
Originally Posted by Troubleshooter View Post
Update: Existing installations of Dallas Phasing are allowed to remain.
So new installations are on hold for a while?
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Old 11-23-2010, 11:45 AM
 
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Quote:
Originally Posted by Bowie View Post
So new installations are on hold for a while?
No new installations of Dallas Phasing will be allowed.

The reason existing installations can remain is the expense of converting many intersections to flashing yellow arrows. Some older signal controllers can't do flashing yellow arrows.
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