So you saw a yellow street sign shaped like a diamond with the silhouette of a man driving a tractor on it. What does that mean, you ask? Or what about that brown sign you saw by the park? And, by the way, what sort of materials are those signs made of anyway? The answers to these questions and more can be found in the much anticipated millennium edition of the Manual on Uniform Traffic Control Devices (MUTCD), which will be available this year. It's the first full revision of the manual in 22 years. And, for the first time, it will be available electronically. You can find it via the Federal Highway Administration Web site at: http://mutcd.fhwa.dot.gov.

MUTCD, which was first published in 1935, contains all national design, application, and placement standards for traffic control devices. The purpose of these devices, which includes signs, signals, and pavement markings, is to promote highway safety, efficiency, and uniformity so that traffic can move efficiently on the streets and highways.

MUTCD was last revised in 1978, and the most recent fully updated edition appeared in 1988.

Information on the MUTCD Web site is organized in four categories: knowledge, resources, communication, and services.

The knowledge section contains the most current information on proposed amendments, the 1998 MUTCD amendments, and the amendment process. There's also an overview of traffic control devices, states that use or adapt MUTCD, and a section on frequently asked questions.

But if you still have questions, you can check out the resources section. Here you'll find e-mail addresses for FHWA representatives who are overseeing the revision of specific MUTCD sections. There are also links to other FHWA safety-related programs; federal agency programs; and Internet resources on highway safety, private-sector associations, and other organizations concerned with improving safety on our highways.

You can also use the communication section to ask questions or to share information with government and industry technical experts. The MUTCD Web site is structured to promote two-way communication. There is a mailing list and an online discussion group. The mailing list is essentially a form of e-mail that affords a quick exchange of information, while the discussion group, although it can be used like a mailing list, is intended to support the focused and facilitated collection and exchange of information and/or knowledge that addresses specific matters or issues of those concerned with applying and maintaining traffic control devices.

Finally, the services category is where you can find additional resources related to MUTCD. There are publications, associations, and other agencies that sell or provide resources. Here's where you can find appropriate National Highway Institute courses, providers of videos, booklets, flyers, and other media related to traffic control devices and their use.

But if you need something fast, you can also search the entire site by keyword. Or take a quick site tour that reviews how information is organized.

Bound copies of the manual will be available for purchase this spring. The Government Printing Office (www.gpo.gov) and major transportation and public works organizations will sell the manual in bound and CD-ROM versions.

Melissa A. Winn is assistant editor of Public Roads and is employed by Avalon Integrated Services Corp. of Arlington, Va.