How transportation systems talk to each other - standards for intelligent transportation systems

Public Roads, Sept-Oct, 1999 by David Smallen

It was 1934, and some visionaries thought radio was the future of communications. Imagine people sitting in their living rooms and hearing live performances from the best entertainers in the business.

But radio broadcasters had a problem; there were no rules. When listeners turned on their radios, they didn't know what they were going to hear. New stations were starting up, and sometimes more than one station was broadcasting on the same frequency.

At that point, the federal government stepped in. The creation of the Federal Communications Commission (FCC) with the authority to regulate radio broadcasting led to radio becoming one of the most important communications technologies in America since that time.

Today, in a less dramatic fashion, the Federal Highway Administration (FHWA), the American Association of State Highway and Transportation Officials (AASHTO), and other organizations are in the midst of a process that will ensure that the pre-1934 chaos of radio broadcasting is not repeated as state and local governments develop and deploy intelligent transportation systems (ITS).

FHWA, AASHTO, the Intelligent Transportation Society of America (ITS America), and a number of other groups, known as standards development organizations (SDOs), have divvied up the action and are engaged in the painstaking, time-consuming process of creating standards for the deployment of ITS.

How Important Are Standards for Transportation?

AASHTO was founded in 1914 primarily to establish standards among the states that were in the formative stages of their road-building programs. The AASHTO "Green Book" is still the primary source of standards for road design.

New York City learned the importance of standards when it took over the operation of the privately owned subways in 1940. The Interboro Rapid Transit (IRT) System was built with a more narrow track gauge than the Brooklyn-Manhattan Transit (BMT) line and the city's own Independent (IND) line. In the past four decades, the operations of the BMT and IND lines have been merged; cars are used interchangeably; and routes have been coordinated. The IRT system still operates separately with the need for separate equipment orders.

"The biggest single retardant in the deployment of ITS is the lack of standards," said David J. Hensing, deputy executive director of AASHTO. "Proprietary systems are secret. It's important to have national, nonproprietary standards."

FHWA, AASHTO, ITS America, and the SDOs are working to ensure that despite the increasingly rapid pace of ITS deployment, the systems nationwide will be compatible. ITS is the application of advanced information, communications, and computer technology to highway and transit systems for programs such as traffic management, public transportation management, emergency management, traveler information, advanced vehicle control and safety, commercial vehicle operations, electronic payment, and railroad grade-crossing safety.

ITS is in the early stages of what is projected to be a multibillion dollar deployment across the nation. Many state and local officials are making their initial decisions about the systems that will be needed in their regions and about the technology to be used to make the systems work effectively.

National standards are especially critical for ITS deployment. The core purpose of ITS is to improve communications so that localities and regions are linked together in a way that results in an improved transportation system. ITS will create "a system of systems" in which there is "interoperability," according to Christine Johnson, director of the Department of Transportation's Intelligent Transportation Systems Joint Program Office.

"Conformance with the National Architecture [a framework for the development of a nationwide ITS infrastructure] and development and use of applicable standards will get us there. ITS uses advanced technology to save time, lives, and money," she said.

The integration of systems allows information from one system to be passed to another, rather than using multiple sensors or systems to accomplish the same task. This integration allows individual components of ITS to work together. According to studies, the benefits provided by an integrated transportation system include fewer accidents, decreased travel time, decreased delay, decreased fuel consumption, and reduced emissions.

The goal of interoperability will only be achieved if all the players are using the same playbook. The first part of the playbook was the National ITS Architecture that the Department of Transportation (DOT) published in 1996 to establish the basic elements to be included in the system This architecture has been very highly regarded and has served as the model for the architecture of ITS infrastructure in several European and Asian nations.

The National ITS Architecture

The National ITS Architecture provides a common structure for the design of intelligent transportation systems. It defines the framework around which regional decision-makers can select a design that is tailored to meet their specific needs. For example, the architecture defines the functions such as traffic signal control, freeway management, or incident management that must be performed by components or subsystems; where these functions reside (roadside, traffic management center, or in-vehicle); the interfaces and information flows between subsystems; and the communications requirements for the information flows (wireline or wireless).