With the advent of the Internet and advances in wireless communications, the role of telecommunications in transportation operations has changed dramatically over the last 20 years. Since 1987, when the Federal Highway Administration (FHWA) first published the Communications Handbook for Traffic Control Systems, faster and more powerful technologies have enabled transportation professionals to improve the speed, performance, and effectiveness of the communication systems that help them manage traffic.

"The original versions of this handbook focused on communications for traffic signal devices," says Shel Leader, telecommunications consultant and author of the newest version. "In the past 10 years, however, we have seen a significant amount of change and advancement in the telecommunications industry. This created a need to update the previous communications handbook."

In the latest update to the handbook, FHWA offers an overview of today's telecommunications technology for transportation professionals who operate traffic signals or manage roadway networks. The Telecommunications Handbook for Transportation Professionals (FHWA-HOP-04-034) is available online at http://ops.fhwa.dot.gov/publications/telecomm_handbook.

From Top to Bottom

Divided into 10 chapters and several appendices, the handbook begins with information on the fundamentals of telecommunications and definitions of basic technologies, such as fiber optics, video multiplexing, and Ethernet systems. The second chapter explains the relationship between the design of telecommunications systems and the National Intelligent Transportation System (ITS) Architecture, which was developed within the transportation industry to serve as the definitive framework for guiding deployment of ITS technology in the United States during the next 20 years. The National ITS Architecture provides strategies for deploying several generic types of telecommunication systems, including vehicle-to-vehicle systems and dedicated short-range systems—devices used to communicate over distances of less than 300 meters (1,000 feet), as in vehicle-to-roadside systems.

The next several chapters provide technical details on the structure, design, installation, and maintenance of telecommunication systems used for transportation purposes. Chapter 4, for example, describes a systems engineering approach to designing communications systems that meet traffic and transportation requirements. Chapter 5 includes an indepth discussion of how field devices, such as traffic signals and freeway management systems, should be configured to meet specific requirements and follow certain procedures. For example, the deployment of traffic and transportation control devices requires the use of National Transportation Communication Interface Protocols, procedures that enable devices made by different manufacturers to work within the same transportation system. Chapter 6 describes what agencies should do to maintain telecommunications systems and how to create a maintenance inventory and budget.

"Anyone working on transportation projects that involve telecommunications would benefit from this book, especially from chapters 2, 4, and 6," Leader says. "Chapter 2 provides basic information on telecommunications, while chapter 4 focuses on the qualifications of individuals responsible for development of communications systems. Chapter 4 also discusses how to involve those individuals in a highway construction project that involves freeway management systems. Chapter 6 explains the difference between a warranty and a service (maintenance) agreement." According to Leader, too many staff members at transportation agencies are not clear on the difference between the two.

In the Real World

In addition to the information described above, the hand-book includes a chapter on how telecommunication systems have been implemented effectively in real-world situations. The analysis includes a case study on the Utah Department of Transportation's strategies for updating its advanced traffic management system, known as CommuterLink. The agency will replace its telecommunication technologies with a more advanced system that uses less hardware and relies on the Internet to transmit traffic information. Although the update will not be completed until 2006, Web users can visit the current CommuterLink site at www.commuterlink.utah.gov/ie.htm.

Another case study describes how Irving, TX, upgraded its telecommunications and traffic signal system to provide centralized control of the city's traffic information. These two case studies illustrate that similar problems may be solved using different telecommunication system designs, some of which rely on the Internet. Each solution can be customized to meet the needs of the end users.

The handbook concludes with a discussion of the Internet and a chapter on what the future may hold for telecommunications in the transportation sector. One future trend will be the use of Radio Frequency Identification (RFID) tags and seals. Transportation agencies will have the ability to embed the tags in roads or roadside structures and use the tags to identify locations that need repair or restoration. For more information on RFID tags and seals, visit http://ops.fhwa.dot.gov/freight/publications /eseal_wp_final_july12/eseal_wp_final _04.htm.

Other Telecommunications Topics

In addition to the new handbook, the U.S. Department of Transportation (USDOT) and FHWA offer several other resources for transportation professionals interested in telecommunications, including training offered through the FHWA Resource Center. "We already have provided training courses to many agencies," says Paul Olson, an ITS specialist at the FHWA Resource Center who assisted in developing the handbook. "And over the next several months, we will put on telecommunications seminars in Idaho, Indiana, and Ohio." The Resource Center also is available to work with agencies to review telecommunications plans and specifications.

For more information on major telecommunication initiatives within the USDOT's ITS Joint Program Office, visit http://www.its.dot.gov/telecom/index.htm. The National Highway Institute also offers a 1-day course, ITS Telecommunications Overview (#137005A), which provides a broad introduction to telecommunications technologies, the associated issues, and practical lessons learned in the application of ITS technologies.

Keri A. Funderburg is a contributing editor for PUBLIC ROADS.