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…On Green Balls.

Posted by Steve on December 5, 2008

“Green” means “stay the hell put, dipshit.”

What, you were expecting perhaps “‘Green’ means ‘go'”? Well, it sort of does – but not necessarily.

Let’s consult our good friend, the MUTCD. That’s the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (“2003 Edition with Revisions 1 and 2 Incorporated, dated December 2007” if you want to get specific about the current version). Pronounced… well, most people I think say “Emm-you-tea-see-dee”, but I always say “Mutt CD”… it’s the picture book that’s the starting point in any discussion of traffic control signs, pavement markings, traffic signals, barricades, those little posts with a reflector on them, etc. It is the starting point because federal law – specifically, 23 CFR Part 655.603 (based on 23 USC §109(d) and §402(a)) – says so. Specifically, the pertinent regulation states:

The MUTCD approved by the Federal Highway Administrator is the national standard for all traffic control devices installed on any street, highway, or bicycle trail open to public travel in accordance with 23 U.S.C. 109(d) and 402(a). For the purpose of MUTCD applicability, open to public travel includes toll roads and
roads within shopping centers, parking lot areas, airports, sports arenas, and other similar business and/or recreation facilities that are privately owned but where the public is allowed to travel without access restrictions. Military bases and other gated properties where access is restricted and private highway-rail grade crossings are not included in this definition.

States are required to do one of three things: 1)Adopt the National MUTCD as the State MUTCD, 2)Adopt the National MUTCD with a State Supplement, or 3)Adopt a State MUTCD that is “in substantial conformance” with the National MUTCD. So, the FHWA’s MUTCD: it’s the standard for traffic control.

Now that that’s out of the way, let’s look at what the MUTCD says about the green ball. For this, we must turn to Chapter 4D: Traffic Control Signal Features. And more specifically, Section 4D.04: Meaning of Vehicular Signal Indications and Section 4D.05: Application of Steady Signal Indications.

So… let’s take a read:

Section 4D.04 Meaning of Vehicular Signal Indications

The “Uniform Vehicle Code” (see Section 1A.11) is the primary source for the standards for the meaning of vehicular signal indications to both vehicle operators and pedestrians as set forth below, and the standards for the meaning of separate pedestrian signal indications as set forth in Section 4E.02.

The following meanings shall be given to highway traffic signal indications for vehicles and pedestrians:

1. Steady green signal indications shall have the following meanings:
1. Traffic, except pedestrians, facing a CIRCULAR GREEN signal indication is permitted to proceed straight through or turn right or left except as such movement is modified by lane-use signs, turn prohibition signs, lane markings, or roadway design. But vehicular traffic, including vehicles turning right or left, shall yield the right-of-way to other vehicles, and to pedestrians lawfully within the intersection or an adjacent crosswalk, at the time such signal indication is exhibited.
2. Traffic, except pedestrians, facing a GREEN ARROW signal indication, shown alone or in combination with another signal indication, is permitted to cautiously enter the intersection only to make the movement indicated by such arrow, or such other movement as is permitted by other signal indications shown at the same time. Such vehicular traffic shall yield the right-of-way to pedestrians lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
3. Unless otherwise directed by a pedestrian signal head, pedestrians facing any green signal indication, except when the sole green signal indication is a turn arrow, are permitted to proceed across the roadway within any marked or unmarked crosswalk. The pedestrian shall yield the right-of-way to vehicles lawfully within the intersection at the time that the green signal indication is first shown.


C. A steady CIRCULAR GREEN signal indication shall be displayed only when it is intended to permit traffic to proceed in any direction that is lawful and practical.

Key, key element in 4D.05 Standard:C there (FYI each MUTCD Section is split into some combination of Standard, Guidance, Option, and Support. As my professor always explained them, “Shall, Should, May, and Why”): to permit traffic to go anywhere that’s legal and practical. So, even without an R10-7 “Do Not Block Intersection” sign… if you’re facing a green light but the receiving lane is full, then that green does not mean “go”, it means “stay the hell put, dipshit!” since there’s nowhere for you to go. The queue in the receiving lane means that the receiving lane isn’t a practical direction for you to go.

Let’s illustrate this concept!

What we have is Car 1 driving north. They have a green light, they can go! But wait: traffic’s backed up in the receiving lane, and the queue’s long enough that when Car 1 enters the intersection, they won’t be able to exit it – Car 2’s right there, blocking them! So, Car 1 will have to wait until all those cars in front of Car 2 move forward and Car 2 moves forward so that Car 1 can finally finish driving north across the intersection. If the phase changes and northbound goes red while eastbound and westbound traffic have a green, Car 3 won’t be able to go anywhere if Car 1 hasn’t cleared the intersection:


In the above image, Driver 1 has shown himself to be an asshole and has created gridlock. He entered the intersection knowing that he couldn’t get out, because Driver 2’s car was stopped there in front of him. Basically, he was hoping that 2 would be able to pull forward and he’d be able to clear the intersection before the signal changed. That was the wrong thing to do. What he should have done was wait at the stopbar until 2 pulled forward. If 2 pulled forward before the light changed, 1 would have been able to cross the intersection then, and the commutative property applies to “Wait, start crossing, finish crossing” and “Start crossing, wait, finish crossing” with regard to how long it takes 1 to get across the intersection – regardless of whether “for the light to turn green again” is part of the wait. However, if 2 was unable to move forward before the signal changed, 1 wouldn’t be blocking the intersection and screwing 3 over by “blocking the box” (the fine for which ranges at least to $200 in Virginia, and I’m told can go as high as $500 in Miami).

“Damn,” you might think, “That is obvious.” WRONG! At least, judging by the number of people I’ve seen block an intersection, it isn’t obvious. Then again, maybe it isn’t that people are too stupid to realize that… maybe they’re just too self-absorbed to care that they’re doing something incredibly rude and minorly illegal.

Either way, in my opinion it should be legal for 3 to t-bone 1 in that second picture.

One Response to “…On Green Balls.”

  1. […] I can name is Norman Mineta) will put out the final rule (the MUTCD’s legal status has been previously explained on this blog) and the 2009 Edition will come out. Now you know about it, and now you can take a look at the […]

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