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Memorandum: AMBER Alert - Use of Changeable Message Sign, August 16, 2002

Canceled on January 15, 2010; Superseded by the MUTCD, 2009 Edition

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U.S. Department of Transportation
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Subject: INFORMATION: AMBER Alert - Use of Changeable Message Sign (CMS)
August 16, 2002
From: Jeffrey F. Paniati
Acting Associate Administrator for Operations; Acting Director, ITS Joint Program Office
Reply to
Attn of:

To: Division Administrators Empty Cell

The AMBER (America's Missing: Broadcast Emergency Response) Plan Program is a voluntary program through which emergency alerts are issued to notify the public about abductions of children. The FHWA recognizes the value of the AMBER Plan Program and fully supports the State and local governments' choice to implement this program. These child abduction alerts may be communicated through various means including radio and television stations, highway advisory radio, changeable message signs (CMS), and other media. The purpose of this memorandum is to clarify the FHWA policy on the use of CMS for displaying AMBER Alert child abduction-related messages. Under certain circumstances, using CMS to display child abduction messages as part of an AMBER Plan Program has been determined to be consistent with our current policy governing the use of CMS and the type of messages that are displayed.

The AMBER Plan Program encourages use of the most effective methods to communicate with the public on behalf of abducted children. We note that CMS is not always the most effective or safest method to disseminate information related to child abductions. The CMS can convey only a limited amount of information to motorists. When there is a need to provide extensive information to motorists, it is critical that other types of traveler information based media (e.g., 511, highway advisory radio, web sites, commercial radio) be used, or that the messages displayed on a CMS supplement these other media. We continue to discourage the display of general public information or other nonessential messages on CMS.

As stated in the January 19, 2001, Policy Memorandum, "INFORMATION: Use of Changeable Message Sign (CMS)" (, FHWA supports the use of a CMS as a traffic control device to safely and efficiently manage traffic by informing motorists of roadway conditions and required actions to perform. It is FHWA policy that the appropriate use of a CMS and other types of real-time displays should be limited to managing travel, controlling and diverting traffic, identifying current and anticipated roadway conditions, or regulating access to specific lanes or the entire roadway. The memorandum does, however, provide for limited use of CMS for driver safety-focused messages. If driver safety- focused messages are to be displayed on a CMS, they should be kept current, be of short duration, and relate to a specific safety campaign.

If public agencies decide to display AMBER Alert or child abduction messages on a CMS, FHWA has determined that this application is acceptable only if (A) it is part of a well-established local AMBER Plan Program, and (B) public agencies have developed a formal policy that governs the operation and messages that are displayed on CMS.

(A) A local AMBER Plan Program would include written criteria for issuing and calling off an AMBER Alert, procedures on issues to coordinate with local agencies and other interests, and conforms to the recommendations of the national program ( Specific criteria for issuing an Alert and the associated procedures may include:

  1. Confirmation that a child has been abducted,
  2. Belief that the circumstances surrounding the abduction indicate that the child is in danger of serious bodily harm or death, and
  3. Enough descriptive information about the child, abductor, and/or suspect's vehicle to believe an immediate broadcast alert will help.

(B) The formal public agency policy and procedures relating to displaying AMBER Alert or child abduction messages on CMS must address the following issues:

  1. The criteria under which CMS will be used for AMBER Alerts.
  2. Clear identification of the law enforcement agency responsible for issuing the alert (e.g., State police, local police department, etc.).
  3. Agencies, interests, and persons to be contacted and information to be disseminated to initiate or call off an AMBER Alert.
  4. Specific recognition that traffic messages, such as lane closures, fog alerts, detours, etc., are the highest priority, and circumstances under which the AMBER Alert message could or could not be displayed.
  5. Length of time to display the message (should be of short duration, typically a few hours). (Note: 4 and 5 should be defined in cooperation with the responsible law enforcement agency based on the specific circumstances of the abduction.)
  6. Geographic area over which the information is to be displayed (should be limited to a reasonable search distance that is reachable within a few hours).
  7. Circumstances that would cause the discontinuation of use of the CMS if the AMBER Alert message creates an adverse traffic impact such as queues, markedly slowing of traffic, etc.
  8. Format and content of the messages to be displayed. Agencies should follow the recommended national CMS practices related to the development, use of text, manner in which messages should be displayed, and how CMS are operated.

A list of references that identify these recommended national practices is attached. Additionally, the 25 agencies in the TMC Pooled Fund Study will be publishing this fall a technical reference that will provide guidance on agency policies and procedures governing CMS operation, how to develop and display messages, and how to operate CMS. Additional information about the TMC Pooled Fund Study and this project is available at:

Finally, questions have surfaced on the linkage between this CMS policy and the Manual on Uniform Traffic Control Devices (MUTCD). Section 2A.07 of the MUTCD states that a CMS shall conform to the principles established in the MUTCD related to the use of signs within the right-of-way of all classes of public highways, and to the extent practical, the design and applications prescribed in Sections 2E.21 (General: Changeable Message Signs), 6F.02 (Temporary Traffic Control Zone Devices: General Characteristics of Signs), and 6F.52 (Temporary Traffic Control Zone Devices: Portable Changeable Message Signs). Through the Notice of Proposed Amendment (NPA) process FHWA is proposing revisions to the MUTCD language regarding use of driver safety-focused messages.

Questions regarding this policy statement should be directed to Mr. Jeff Lindley at (202) 366-6726. For further information regarding message content, display, and CMS operation, please contact Mr. Jon Obenberger at (202) 366-2221, or for information on the MUTCD contact Mr. Ernie Huckaby at (202) 366-9064.