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How transportation systems talk to each other.

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).

The National ITS Architecture is the framework. It identifies the information that is to be exchanged among various ITS functions (or subsystems) without specifying how the exchange will take place. However, it does identify where standards - the second part of the playbook - are needed to specify how ITS components are to be interconnected and to provide uniform data definitions.

For example, the architecture tells us what information should be sent to or transmitted from a traffic management center, and the standards give us the specifications for how this will be accomplished.

The Standards Development Process

Just as customers of different telephone companies around the world can communicate with each other because compatible technology is used, standards will promote compatibility among regional and local ITS systems that are made at different times by different manufacturers. Adherence to national ITS standards will ensure that ITS devices will continue to function as travelers and commercial operators move by car, truck, or transit between cities or across borders.

The standards development process that is now underway is addressing both standards and protocols. Standards specify how various technologies, products, and components must perform when used in combination or interchanged. Protocols, which define how data are to be exchanged, cover addressing, security, priority, and other data handling information.

A key part of the process is the development of "open" standards under which different manufacturers may submit competing bids. The competitive process is likely to produce lower costs and better technology than proprietary systems that are owned by a single company. It will also mean that agencies will not be limited to using a particular vendor for ITS upgrades and enhancements even if that vendor's technology was selected initially.

Michael Schagrin is the coordinator of the Standards Program of the ITS Joint Program Office. He is in charge of coordinating the efforts of various national and international organizations to identify the need for voluntary and regulatory standards to support ITS deployment. He also manages five DOT-funded standards efforts within various standards development organizations.

"Since 1996, our focus has been on the development of standards. We currently have 80 activities operating - that is, standards that are either published, in [the approval process], or under development," said Schagrin.

Under the 1996 contract that was signed with the five SDOs, DOT provides funding for technical assistance and travel funds for public-sector participants.

Roy Courtney, ITS America's senior standards engineer, said the ITS architecture, standards, and deployment are a continuum of activity.

"You can't look at one part of it as a stand-alone piece. It's continually changing. It's like a river. You can't take a snapshot that will remain accurate," Courtney said.

ITS standards development will remain a continuing process - from the determination of a need through the development by an SDO, approval of the SDO's membership, publication by the SDO, and adoption of the standard by DOT. The process does not end at that point because use of the standards and technological advances may lead to the consideration of additional changes.

Courtney credited leaders inside and outside of DOT in the mid-1990s with having the vision to establish a process that would lead to ITS deployment.

"It took a vision - five, six, seven years ago - to see that standards were needed, and before standards, we needed an architecture," he said.

High-Priority Standards

A 1996 survey by ITS America and DOT found a desire for quick action to set standards on several high-priority areas. The areas were:

* National Transportation Communications for ITS Protocol (NTCIP) and Transit Communications Interface Protocol (TCIP), which address systems such as dynamic message signs, traffic signal controllers, environmental-sensing stations, highway radio advisory, closed-circuit television to monitor traffic, freeway ramp meters, and traffic/transit management center-to-vehicle interfaces, and traveler information services.

* Location Referencing Message Set (LRMS), which is crucial to electronic in-vehicle navigation, for emergency signaling (Mayday) purposes, for locating incidents for incident management, for fleet (transit bus) management, and for stolen-vehicle location.

* Commercial Vehicle Information Systems and Networks (CVISN) standards - such as weigh-in-motion, credential verification, fleet management, and driver safety - to increase the safe operations of commercial vehicles. CVISN standards include electronic data interchange and dedicated short-range communications.

* Dedicated Short-Range Communications (DSRC), which are important to the areas of rapid and convenient toll collection, electronic fare payment, electronic clearance of commercial vehicles past inspection and weigh stations, and parking fees.

* Data Dictionaries and Message Set Templates for advanced traveler information, traffic management, and transit.


Under the 1996 cooperative agreement, five organizations, in consultation with FHWA, agreed to work on the development of non-proprietary standards that would be consistent with the National Architecture. The SDOs are attempting to attain a technical consensus that balances market forces and user needs. The membership of each organization will be voting on the standards that have been developed by their representatives.

The five SDOs and the areas in which they are working are:

* AASHTO - the National Transportation Communications for ITS Protocol.

* American Society for Testing and Materials (ASTM) - Dedicated Short-Range Communications Physical and Data Links.

* Institute of Electrical and Electronics Engineers (IEEE) - ITS Data Dictionary and Message Set Template, DSRC Message Set, Incident Management Message Set, and ITS Data Registry.

* Institute of Transportation Engineers (ITE) - Advanced Traffic Controller, Advanced Traffic Management System Data Dictionary, Traffic Management Center Message Sets for External Communications,Transit Communications Interface Profiles.

* Society of Automotive Engineers (SAE) - Advanced Traveler Information System Data Dictionary and Message Set, High-Speed FM Subcarrier Messages, ITS Data Bus, Location Referencing, Mayday Reporting, Navigation and Route Guidance System Man-Machine Interface, Safety and Human Factors.

The first standard, "Serial Communications Between MicroComputer and Heavy Duty Vehicle Applications,' was published in 1996. Since then, 21 more standards have been approved; 35 are in ballot; and 23 are in development.

TEA-21 and Standards

The Transportation Equity Act for the 21 st Century (TEA-21), signed by President Clinton on June 9, 1998, wrote ITS standards into the nation's transportation law. The act required DOT to submit a report to Congress by June 1, 1999, "identifying which [ITS] standards are critical to ensuring national interoperability or critical to the development of other standards and specifying the status of the development of each standard identified."

TEA-21 also directed the secretary of transportation to issue provisional standards for any standards identified as critical for which a standard has not been endorsed and published by Jan. 1, 2001.

In its report to Congress, Intelligent Transportation Systems: Critical Standards, DOT defined a critical standard in two ways. A "national standard" is one that would ensure that large numbers of users, particularly mobile users, can readily access available ITS services anywhere in the nation, and a standard required by other critical standards was termed a "foundation standard."

In the report, Secretary of Transportation Rodney E. Slater said, "TEA-21 requires us to identify which standards are critical to ensuring national interoperability or critical to the development of other standards. This report identifies those critical standards. However, it does not address many other equally important ITS standards, such as standards that are important for public infrastructure, transit, or safety, which the Department is also committed to seeing developed."

DOT's report to Congress, listing the critical standards, is available on the Internet (

TEA-21 also requires that federal funding will be withheld from any project that does not conform to the National Architecture, applicable standards or provisional standards, and protocols. This conformity requirement applies to all ITS standards and not just to those on the critical list. Interim guidance on how to achieve conformity was published in October 1998 by DOT; the final regulations on conformity are in preparation.

The National Transportation Communications for ITS Protocol

The most successful area for standards development has been NTCIP, which is a family of standards that provides the rules for communicating and the vocabulary necessary to allow electronic traffic control equipment from different manufacturers to operate with each other as a system. It allows the purchaser to mix and match equipment from different manufacturers and reduces reliance on expensive, proprietary systems.

The NTCIP standards have been a joint effort of AASHTO, the National Electrical Manufacturers Association, and ITE. The initial overview of the NTCIP family of standards was published in December 1996 as a foundation for the more detailed, related standards in the same family. Since then, six other NTCIP standards have been endorsed.

The NTCIP standards are necessary for the exchange of messages between communication command centers and roadside features such as dynamic message signs, traffic cameras, traffic signals, ramp-metering devices, and traffic advisory radio.

"We are working very hard for deployment based on non-proprietary protocols so we can give purchasers alternatives," Hensing said.

"Some local government are already purchasing equipment based on the NTCIP standards," said Courtney.

"We are going to provide an improved driving experience for the American citizen," Courtney said. "People will be able to negotiate the roads more safely and more quickly. They will be informed about their travel environment. We will be using loop detectors and cameras more frequently. As we make more data available to traffic command centers, they will be able to control traffic on the surface of the earth [in the same] way air traffic controllers have been controlling air traffic for most of the 20th century. They will be able to help the American public move from place to place. ITS is using advanced technology to save lives, time, and money in ground transportation."

Dedicated Short-Range Communications

The DSRC systems use microwave communications over very short distances to allow moving vehicles to communicate with fixed roadside locations. They are currently used for applications such as electronic tolling, electronic clearance of commercial vehicles at weigh stations, and signal priority for transit vehicles.

"Most of the systems that are currently deployed are proprietary" Hensing said. "They work well, but they're not compatible nationwide. The saving grace is that not many people who use the tolls in the Northeast want to use the tolls in Texas. But commercial vehicle operations (CVO) need compatibility. The nature of trucking services means that the technology needs to be nationwide and compatible. We need to resolve the situation."

For CVO, transponders are primarily used for bypassing trucks and buses that are within legal weight limitations and, to a limited extent, to check credentials and safety status. The goal is to expand the clearance process to provide credential and safety checks at highway speeds, given the capability for a real-time supporting information system infrastructure. Credentials and safety checks could consist of registration, fuel tax, insurance, permits, out-of-service orders, and safety indices.

The developing problem is that states using a particular system for electronic screening of trucks and buses on the highway have not found an equitable way of sharing transponder codes with other states using another system. This has resulted in confusion over equitable reimbursement to one group for allowing the use of transponders to another group.

DOT has a goal of achieving national interoperability between electronic screening systems, as well as other safety and credentials components of the CVISN architecture. To achieve this will require coordinated discussion with all states to eventually establish uniform operating procedures. Discussions are now taking place through AASHTO and the Commercial Vehicle Safety Alliance and between states and organizations like HELP Inc. and NorPass that provide electronic screening support.

Testing the Standards

DOT is now moving into the process of testing the standards - to "prove the standards in realistic transportation settings under realistic conditions." In March, a 30-month contract was signed for a team led by Battelle Memorial Institute to manage the testing program.

The ITS Standards Test Team (ISTT) has identified about 55 standards to be tested. The remainder, such as data dictionaries, were deemed not testable.

The team then worked to determine how the standards worked together and which standards should be tested as a group - an analysis called a taxonomy.

"The team is looking for multiple sites capable of testing clusters of standards similar to those identified in the National ITS Architecture's market packages," said Schagrin.

"Testing standards in the field will help us identify any bugs in the standards as well as provide real-world experience and confidence in using the standards."

The review of the testing results will be a consensus process as has been used by the SDOs. The NTCIP standards will be among the first tested because they are the most mature. They are already being used in the field.

Courtney said that successful testing should give a major boost to ITS. Once state and local government officials learn of successful testing, the ITS program will start to move more quickly. However, he predicted, it may be several years.

"Right now, there is a lack of forward motion. Things are going slowly. If it is shown that a suite of standards has been endorsed and works, people will want to buy. A lot of the standards haven't been validated in themselves. We have to make sure they're self-consistent and then test them in clusters to determine if they work together," Courtney said.

A Step Toward Interoperability

Schagrin, however, emphasized that the adoption of technically acceptable standards is only one step toward achieving interoperability.

"Standards are necessary, but they are not necessarily sufficient,' he said. "Interoperability requires accepted standards, institutional agreements that are cross-jurisdictional agreements, and agreements on operating procedures in the back office. Really achieving interoperability is more difficult than achieving technical standards."

David Smallen is the president and chief executive officer of David Smallen Associates, a consulting/writing/editing company in Washington, D.C. For 14 years, he served on Capitol Hill, starting as press secretary and then director of communications for the House Committee on Public Works and Transportation and as senior staff member of the House Subcommittee on Investigations and Oversight. Before that, he was a newspaper and news service reporter. He has a bachelor's degree from Duke University, and he attended the graduate school of journalism at the University of North Carolina.
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Title Annotation:standards for intelligent transportation systems
Author:Smallen, David
Publication:Public Roads
Date:Sep 1, 1999
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