The Traffic Signal Network

Keep The Red Arrows in The U.S.A.

by Arthur J. Dock

Should left-turn red arrows be kept or be replaced with a red ball? The FHWA is proposing a standards change that would require just that.

  • The FHWA proposes to revise Section 4D.6 to delete this paragraph which reads, "RED, YELLOW, and GREEN left-turn-ARROW indications only. Only one of the three lenses shall be illuminated at any given time. A signal instruction sign shall not be required with this set of signal indications. If used, it shall be a LEFT ON GREEN ARROW ONLY sign (R10-5) or,". This deletion would require a CIRCULAR RED signal indication to be used instead of a RED ARROW for left-turn indications. This is in response to older driver research that shows confusion as to the meaning of the red arrow indication. (National Committee on Uniform Traffic Control Devices (NCUTCD) Part 4 Comparison Log Rewrite Comments)
  • Where did this idea come from?

  • RED ARROW SIGNAL INDICATIONS – Research summarized in the Older Driver Highway Design Handbook shows that RED Arrow indications are less comprehensible than CIRCULAR RED displays and potentially unsafe interpretations were found for RED ARROW displays in protected-only right and left turn operations. The CIRCULAR RED display received significantly fewer violations than the arrow when used for right turns. One study even concluded, "the right turn RED ARROW is not a safe traffic control device." The FHWA is therefore proposing the elimination of the RED ARROW… The compliance date for these proposals that eliminate the RED ARROW would be 3 years after the publication date of the final rule. (National Committee on Uniform Traffic Control Devices (NCUTCD) Part 4 Comparison Log Rewrite Comments).
  • This goes far beyond the cost of replacing a great many indications. The proposed elimination is just one of many changes intended to help older drivers. However, although it is inherently true that a red ball indication has a greater target value than an arrow, there are other issues which mean that this change would result in a confusing and less-logical arrangement that goes against concepts engrained into standard operating principles and practice. Furthermore, in reading the statement above, the strongest statement is against red right-turn arrows which appears to be forcing the conclusion that ALL red arrows must be eliminated. In either case, I believe it sounds as if driver ignorance is the real issue and not the indication itself.

    Is your agency MUTCD compliant? Let’s be clear that we are bound by what is in the MUTCD so if it is changed we must (or should I say "shall") change as well:

    "What is the legal status of the MUTCD?

  • The MUTCD is adopted by reference in accordance with title 23, United States Code, Section 109(d) and Title 23, Code of Federal Regulations, Part 655.603, and is approved as the national standard for designing, applying, and planning traffic control devices.
  • Does this mean that all traffic control devices must comply with MUTCD standards?

  • Yes, all traffic control devices nationwide must conform to the MUTCD. There are no exceptions." (
  • What sort of confusion would happen if red left-turn arrows are replaced with red balls? A red ball is a red ball is a red ball. A left turn red ball looks exactly the same as a red through indication ball. On approaches with both through and left turn phases the proposed standard results in drivers being presented with both a green ball and red ball indication simultaneously

  • "Approach definition: all lanes of traffic moving toward a location from one direction." (1988 MUTCD 4B-8(1a) footnote).
  • This situation exists presently in many locations throughout the United States. What is typically done to help "clarify" the left turn indication and separate it from the through indications? To help ease the confusion, the logical solution (although apparently not required by the updated MUTCD) is to put up a sign (e.g. R10-10L "LEFT TURN SIGNAL") as a supplement. Is this really the best solution?

    The engrained concept referred to earlier is this: provide the user with symbolic and self-explanatory traffic control devices whenever possible. Keep in mind that not everyone in the United States speaks English. This fact is not going to change anytime soon. In reality, it will probably become more of an issue as time goes by. Just as we use symbolic signage and separate, self-evident indications for pedestrians, it makes sense to use separate self-evident indications for vehicular turning movements. Can a driver that cannot distinguish and comprehend the meaning of a red arrow be depended upon to reliably grasp the intention of a combination of a sign and a signal head? As is the case with any traffic control device, driver education and familiarity are key components.

    Color and shape are important cues. Any indication must be seen, recognized, comprehended, and obeyed to be effective. Confusion with indications intended for adjacent lanes just serves to slow down and muddle this important information exchange process. Utilizing an indication that is "shielded, hooded, louvered, and positioned" (1988 MUTCD 4B-6(7c) isn’t always an effective way to differentiate between adjacent indications either (especially at night when the glowing color of any indication is obvious). Differentiating between indications by the use of simple symbolic and color cues is a powerful tool that should not be cast aside. Once again, driver education and familiarity are important.

    Another issue created by this change would be confusion between protected/permitted and protected indications. A protected/permitted phase allows a motorist the opportunity to turn during the green by yielding to oncoming traffic. A protected phase, on the other hand, only allows turns when the green arrow is on. The typical protected/permitted indication utilizes a five-section head such as :

    The proposed standard would require a head such as the one below for protected left turn operation:

    How would a driver approaching these similar indications be expected to understand the differences between them? Furthermore, if this is a far-left indication and is red, how does an approaching motorist differentiate it from a red through indication? Once again, a sign becomes a likely (although, once again, apparently not required by the new MUTCD) option. Which sign(s) should be used? The protected/permitted may need a "LEFT TURN YIELD ON GREEN (symbolic green ball)" (R10-12) and the protected may need a "LEFT ON GREEN ARROW ONLY (R10-5). Once again, a self-evident indication has been replaced by one which requires the additional clarification of signage. Is this really an improvement and absolutely clear in all intersection configurations? Are you sure?

    This standard change begs the question "is the problem with operation, comprehension (familiarity), or visibility?" More restrictive operations should result in lower accident rates with a related effect on capacity. For example, a protected arrow operation should be safer because it in essence lessens the necessity for the driver to make a difficult decision that requires a higher level of skill (i.e. no yielding to oncoming traffic and looking for a gap to turn in). In the realm of comprehension, anyone that has a drivers’ license should be familiar with standard traffic control devices. Finally, even if someone knows what a symbol means, they still need to be able to see it. Visibility in and of itself is indeed an important issue which should be dealt with through good design and implementation practices.

    A well designed and implemented signalized intersection installation has much to do with successfully controlling traffic in a safe and efficient manner. Intersection geometrics and proper installation are all key elements. In my opinion, much needs to be done in this area. For instance, the simple application of backplates can make a big difference in target value:

  • "A back-plate is a strip of thin material which extends outward parallel to the signal face, on all sides of the signal housing to increase the signal target value. Target value enhancement should be used on signals viewed against a sky or bright or confusing background." (1988 MUTCD 4B-11).
  • In fact, another proposed change included in the FWHA update comments strengthens the wording regarding backplates:

  • Backplates – The FHWA proposes to revise Section 4D.17, to insert a new paragraph 16 to provide additional reasoning why a backplate should be used. The new paragraph will read: "SUPPORT – The use of backplates of a size (width) three times the diameter of the signal can be used to assist older drivers in decision- making tasks further from an intersection where the traffic density is lower and there are fewer potential conflicts with other vehicles. The use of backplates also enhances the contrast between the traffic signals and their surroundings for both daytime and nightime conditions." (National Committee on Uniform Traffic Control Devices (NCUTCD) Part 4 Comparison Log Rewrite Comments).
  • If a driver cannot easily pick out the traffic signal for his approach from the background clutter (trees, signs, other vehicles, etc, etc) how can he be expected to obey it? How much less effective is a traffic signal that is swinging and swaying in the breeze on a span-wire than one rigidly mounted on a mast arm? Below are salient quotes, from what should be a familiar document, regarding visibility of signal indications:

  • "Each signal face shall be so adjusted that its indications will be of maximum effectiveness to the approaching traffic for which they are intended" (1988 MUTCD 4B-11)

    "The primary consideration in signal face placement shall be visibility" (emphasis added – 1988 MUTCD 4B-12).

  • The point is simple, make sure that the signal heads are visible so they can be effective. Worry about visibility first and foremost. Cluttering the landscape with confusing indications and signs meant to clarify their meaning is no way to solve the problem.

    If the real issue is indeed confusion about the meaning of the signals among a percentage of the population, perhaps it is the population that needs education and not the symbol which needs changing. Could it be that regional variations in protected phase implementation have resulted in ignorance amongst a percentage of the population with regard to the meaning of red arrows? Could it be simple familiarity more than some mysterious age specific quirk? Shouldn’t this bring us to better driver education as the real topic of discussion?

    One final controversial statement: if we were to drive MAJOR changes in our standards on the basis of user misunderstanding, we had better come up with an alternative to the current pedestrian indication standards long before worrying about red arrows.

    We’d better act fast if we don’t want this proposal to become reality. If you agree that this is not a good change (and perhaps you have better arguments than presented here), please let the FHWA and NCUTCD know before it is too late. Comments are due on or before June 30, 2000 and need to be sent to:

    Docket Clerk

    U. S. DOT Dockets, Room PL-401

    400 Seventh Street, SW

    Washington DC 20590-0001

    Include a self-addressed, stamped postcard if you want notification that your comments were received.

    Please note that all responses to Federal Register notices must be submitted in writing and include an original signature. Refer to "Docket No. 99-6575, RIN 2125-AE71. Proposed amendments published December 30, 1999." in your response. Be heard and help save the red arrows.

    Information regarding the proposed changes is available at:

  • If you have any questions or comments you can reach me at

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