|FHWA Policy Memorandums - Manual on Uniform Traffic Control Devices|
|U.S. Department of Transportation|
Federal Highway Administration
|Subject:||ACTION: "Congestion Ahead" Messages||Date:|
|From:||Christine M. Johnson
Program Manager, Operations
Director, ITS Joint Program Office
The launch this week of 511 traveler information telephone service in Utah reminds us of the interest of the public in knowing more about travel conditions, and of the importance of traveler information to the operations of transportation systems. One of the more visible methods for providing information to travelers is the changeable or dynamic message sign (DMS). According to the ITS Deployment Tracking database, there are nearly 2,000 DMS installed in the major metropolitan areas with hundreds more planned by 2005.
We've all seen the good things that these signs can do, providing road closure notices, warning of hazardous conditions, and, in a few places around the country, providing travel times. We've also seen the pictures in the newspapers showing stopped traffic under a sign displaying a message that says, "Congestion Ahead" or "Expect Delays" or, worse yet, "Normal Conditions." These types of messages, that do not offer meaningful or useful information to travelers, contribute to the erosion of the public's trust in these systems and of the information they provide. As I noted in a memorandum to the Pennsylvania Division earlier this year (available under FHWA Directives and Policy Memorandums at http://www.fhwa.dot.gov/legsregs/directives/policy/pame.htm), "Inaccurate, incomprehensible, or inappropriate information displayed on a [DMS] can … cause motorists to question the credibility and ignore all [DMS] messages."
There are many reasons why ineffective or questionable messages are displayed. They may be initial, computer-generated messages that are being investigated by system operators. The library of messages that is available to operators or computer systems may not be robust enough to provide more detailed information. Perhaps these are the most accurate messages that can be displayed given the imprecise or sketchy data that is available from the roadway. Or there may be agency policies that preclude offering messages with greater details or preferred actions. Regardless of the underlying reasons, the public sees only an ineffectively used, expensive piece of technology. Secretary Mineta has been among those that have expressed frustration with this seeming waste of resources.
We need to work closely with our partners in the operating agencies to ensure that they are designing and using their DMS effectively. There are a number of activities underway to try to help agencies provide better information. A number of these efforts are part of a Transportation Management Center (TMC) pooled fund study that has 21 participants including 18 states, the District of Columbia, the I-95 Corridor Coalition, and FHWA. Additional information about the TMC pooled fund study is available at http://tmcpfs.ops.fhwa.dot.gov. The pooled fund study is initiating a project related to changeable message sign practices, policies and procedures that will produce guidelines to help agencies select appropriate messages. The pooled fund study is also supporting a project in 2002 to develop guidance for TMC operational concepts and performance requirements that should help agencies better recognize how traveler information and transportation management work together.
Another FHWA project is addressing consistency of text-based messages, including DMS. This may result in more robust message libraries for use by operators and computer programs. Other projects include researching techniques for combining (or fusing) various data for use by traveler information systems, resulting in a best practices report; and development of an extensible mark-up language (XML) vocabulary for traveler information that will allow information to be exchanged among agencies more easily. These types of efforts can help create and exchange better traveler information that may be useful in displaying messages on DMS.
Finally there is an effort to encourage increased data collection about traffic and transportation networks. This "infostructure" may result in improved and more detailed knowledge about how transportation systems are functioning. This information could then help create more useful messages for display on DMS. However, it is also important to note that better DMS messages can already be displayed with the information currently available. There is no need to wait for "full" data coverage to begin displaying useful information to the traveling public.
We ask that you take the following actions:
If you or your staff have any questions or wish additional information, please contact Bob Rupert at Robert.Rupert@FHWA.dot.gov or (202) 366-2194.