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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - Fall 1996

Smart Road, Smart Car: The Automated Highway System

by Nita Congress

... I take to the open road,

Healthy, free, the world before me,

The long brown path before me leading wherever I choose.

-- Walt Whitman, "Song of the Open Road"

Convoys of trucks moving along an automated highway -- their distance from each other never varying, their speed never slacking, their course never wavering. ... Despite fitful rain and heavy fog, the bus driver never peers uncertainly into the gloom but unhesitatingly follows roadmarkers, avoids obstacles, and maintains her lane and her speed. ... Platoons of cars follow each other at regular intervals. But when the progress of one car is halted by an emergency, the others smoothly, swiftly, simultaneously shift lanes. ... Automatic braking lets even those with mobility impairments drive cars.

That's the world of the Automated Highway System (AHS). And it's coming soon.

The Vision

America is a nation of cars. But our reliance on cars and a rapidly aging highway infrastructure is compromising our safety, promoting congestion, sacrificing efficiency, and costing us money. Intelligent Transportation Systems (ITS) technologies -- existing and proposed -- offer the best solutions to a broad range of problems. An automated highway system, one which lets control information pass among vehicles and the infrastructure, will combine ITS technologies to maximize safety and efficiency and relieve congestion and associated costs. These technologies will probably include collision warning and avoidance devices, guidance devices, electronic brakes, electronically controlled steering, and other sensors to supplement -- and ultimately, perhaps, replace -- human driving judgment.

"We could go off technically and do something that would work in less time, but we'll come up with a much better plan by listening to the voice of the customer."

The results will be more predictable arrival times; better use of existing roadways, saving the costs of constructing new highways; significant reduction in traffic accidents; conservation of energy resources; reduced travel times; and reduced traffic congestion (see Major AHS Goals).

It's only natural to assume that intelligent systems will be applied in the highway setting. Such systems are permeating all aspects of our work and recreational activities. Also, many of these systems are now or will shortly be available on vehicles. But the AHS story is about much more than the inevitable march of technological progress. It's also a story of partnership and foresight.

The Partnership

The AHS effort is a complex, multifaceted project. Its three phases -- analysis, systems definition, and operational test and evaluation -- span more than 10 years with widespread implementation to follow. The systems definition phase is carried out primarily through a consortium, the National Automated Highway System Consortium (NAHSC). NAHSC is comprised of transportation stakeholders who have an inherent interest in transportation improvements: automotive manufacturers, infrastructure builders, and state/local transportation agencies, which are assisted by top-level academic transportation centers and engineering, communications, and aerospace firms.

"We're going from pie in the sky' to yes, this really will work.'"

Perhaps unique among government-initiated programs, the AHS project does not take a top-down approach to its work. "We aren't the people providing the answers; we're helping define the issues," explains a Federal Highway Administration (FHWA) AHS project manager. A private sector consortium manager concurs, "DOT [the Department of Transportation] has been a very good partner to us. They don't come in thinking they have all the answers; instead, they come in very clearly representing the public interest." Conversely, the consortium members "don't stand there, asking FHWA What do you want me to do with your money?'" This FHWA approach is consistent with the principles of total quality management that recognize the appropriateness and advantages of gaining the participation of stakeholders in defining program priorities and making decisions.

The Automated Highway System Cooperative Program.

The Players

The AHS project is made up of three tiers of participants: core participants, associate participants, and outreach participants.

Including the U.S. government, there are 10 core participants. Each provides high-level expertise in various AHS technologies, program management know-how, and financial resources; each also contributes to the effort's credibility. Specific areas of expertise for the various partners follow:

  • Bechtel -- infrastructure and environment.
  • Caltrans (California Department of Transportation) --infrastructure development and highway operations.
  • Carnegie-Mellon University -- vehicle robotics.
  • Delco Electronics -- vehicle development.
  • FHWA -- federal sponsorship.
  • General Motors -- vehicle development.
  • Hughes Aircraft -- communications and systems engineering.
  • "We ask the stakeholders what they want, they make requests, we listen -- and the program gets changed."

  • Lockheed Martin -- system integration.
  • Parsons Brinckerhoff -- traffic engineering, societal and institutional research.
  • The University of California Partners for Advanced Transit in Highways (PATH) Program -- advanced vehicle control.

The core participants carry out and/or oversee the various tasks associated with the systems definition phase. This includes work toward the 1997 AHS demonstration, AHS concept definition and delineation, case study research, and societal and institutional issues research.

The work program and allocation of tasks are defined by consensus, as are all decisions. This is not an easy task. "Our monthly meetings are very messy," admits one consortium member. "There are lots of arguments, lots of discussion. But we always manage not to get stalled and to keep moving."

A contract team from Mitretek supports FHWA in its NAHSC work. The 80-some associate participants form part of the project's broader foundation of support by representing various stakeholder groups:

  • Vehicle industry.
  • State/local government agencies.
  • Highway design industry.
  • Vehicle electronics industry.
  • Environmental interests.
  • Trucking operators.
  • Transit operators.
  • Transportation users.
  • Insurance industry.

Associate participants support the goals of the program and become involved with the consortium on a voluntary basis to share research results and/or provide stakeholder perspectives on intermediate results. New associates continue to join. Associates define their own level of activity and no financial commitment is required. They receive regular information and updates from the project, are invited to AHS workshops and forums, serve on ad hoc task forces, and are eligible to represent their particular stakeholder category on the NAHSC Program Management Oversight Committee. Representative associates include the American Association of State Highway and Transportation Officials, Argonne National Laboratory, California Highway Patrol, Honda R & D North America, HP Microsystems Inc., ITS America, Ontario Ministry of Transportation, Pennsylvania Turnpike Commission, Robotic Technology Inc., South Coast Air Quality Management District, Toyota Motor Corporation, University of Wisconsin at Madison, and U.S. Army Tank Automotive Armaments Command.

Outreach participants do not actively participate in program activities, but they receive consortium mailings and belong to stakeholder category groups.

Table 1 -- AHS Project Milestones

Date Milestone/Activity
1991 ISTEA mandates development of a prototype AHS.
Dec. 1993 FHWA requests applications for an AHS consortium.
1993 15 precursor systems analysis contracts are let.
Dec. 1994 NAHSC is formed.
April 1995 First NAHSC Workshop
Oct. 1995 System Concepts Workshop
Nov. 1995 Milestone 1 document NAHSC Program Plan and AHS System
Objectives and Characteristics is submitted to DOT.
May 1996 NAHSC Stakeholder Forum
June 1996 Groundbreaking for Technical Feasibility Demonstration
Nov. 1996 Concept Design Workshop
Aug. 1997 Proof of Technical Feasibility Demonstration
Nov. 1998 Concept Selection Workshop
Mar. 1999 AHS Concept Selection
June 1999 AHS Preliminary Design Workshop
Sept. 1999 Prototype Test Plan Workshop
Aug.. 2001 Prototype AHS Demonstration
2002-2006 Operational test and evaluation conducted at sites nationwide.


Major AHS Goals

The AHS program is designed to influence how and when vehicle-highway automation will be introduced. AHS deployments will be tailored to meet the needs of public, commercial, transit, and individual travelers in rural and urban communities. The major goals are to:

Improve safety by significantly reducing:

  • Fatalities.
  • Personal injury.
  • Pain and suffering.
  • Anxiety and stress of driving.

Save money and optimize investment by:

  • Maximizing efficiency of the existing infrastructure investment.
  • Integrating other ITS services and architecture to achieve smooth traffic flow.
  • Using available and near-term applied technology to avoid costs of conventional highway build-out.
  • Developing affordable equipment, vehicles, infrastructure, operations, maintenance, and user fees.
  • Closing the gap on predicted infrastructure needs.
  • Using public/private partnerships for shared risk; using the National AHS Consortium as a global focal point to influence foreign deployment efforts.
  • Reducing fuel consumption and costs, maintenance, wear-and-tear, labor costs, insurance costs, and property damage.

Improve accessibility and mobility by:

  • Improving employee on-time performance, resulting in a more effective work force.
  • Facilitating "just-in-time" deliveries.
  • Improving public transportation service, increasing customer access, and expanding service levels, resulting in increased revenue, reduced costs, and reduced accidents.
  • Achieving a smooth traffic flow, reducing delays, travel times, travel time variability, and driver stress.
  • Making driving more accessible to less able drivers.

Improve environmental efficiencies by:

  • Reducing emissions per vehicle-mile traveled.
  • Providing a solid base for reliable, lower cost transit.
  • Providing an efficient base for electric-powered vehicles and alternative fuel vehicles.

Create jobs by:

  • Providing a stronger national economy and increasing global competitiveness.
  • Increasing jobs in research and development and in early ITS deployment.
  • Facilitating technology transfer (e.g., from military to civilian use).
  • Creating new U.S. automotive products and new technology-based industry to compete in the international marketplace.

A concept drawing of an automated highway system with dedicated lanes in the center of the highway.

The Status

Moving toward a national AHS is a slow, gradual process. Every step must be taken cautiously, carefully, to ensure best use of resources and optimal acceptance by potential users. Also, some of the supporting technology for AHS simply isn't available yet. Consequently, no one expects or even envisions AHS to be deployed on anything other than a highly selective basis in this century.

"We're having to sustain and believe in a vision for a project that's 20 years away," notes an FHWA manager involved in the AHS effort.

Numerous milestones help buoy belief and interest in the long-range project. Table 1 highlights key actions over the project's lifetime.

The Demonstration

One of the most eagerly awaited milestones in the AHS schedule is the August 1997 "proof of technical feasibility" system demonstration. This demo will fulfill the mandate of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) and is going to show Congress, state and local governments, and the public at large that an automated highway system is both practicable and practical -- that AHS is not some futuristic experiment, but a logical outgrowth of today's technologies and needs. Key state and local transportation officials and other leaders will be invited to experience automation as vehicle riders. The exposition will be open to all.

"It's really amazing to sit there and watch this car. The scientist is behind the wheel, and the car is taking a curved course at about 55 kilometers per hour between cones placed about 20 centimeters apart. And you swear he's driving, the car's going so smoothly. Only he doesn't have his hands on the wheel or his foot on the pedals. ..."

The demonstration will not unveil a prototype system. Instead, it will feature a broad array of the very latest and best in sensors and advanced vehicle-control technologies. Some of these will be demonstrated in a full-scale, live exhibition on a 12-kilometer segment of San Diego's Interstate 15 high-occupancy vehicle lanes. At least 20 cars, light trucks, and construction and/or maintenance vehicles will drive this course. Other technologies will be displayed in booths, described in case studies, or presented in simulations. The demo, then, is "a national stage -- the only national stage" for NAHSC participants and other transportation industry members to show off their most useful and promising technologies. "This is the engine that's driving our work, that's bringing it all together," notes an FHWA manager. "It's going to be the most visible event for all of ITS next year."

The Concepts


A representation of the infrastructure-supported AHS concept.

The demonstration has, notes one manager, "forced us to refine our own thinking" about AHS. A parallel consortium activity "down-selection" is doing the same thing.

NAHSC began with some 30 possible concepts for an automated highway system; it now has five. This winnowing, or "down-selecting," process is neither an Olympic heat nor a swimsuit competition; the contenders aren't eliminated so much as blended with each other. The five current concept families (see The Five Concept Families) will be reduced to two or three by the winter of 1997. Gradually, a single preferred "right" AHS concept will emerge, and a prototype will be built.

The consortium's concepts of AHS span a spectrum from almost autonomous smart vehicles at the one end to smart vehicles and smart roads working in combination at the other. Down-selection is, like all of the AHS project, a slow process. That's because it too relies on input from multiple stakeholders. But the process works.

As a consortium manager notes: "We originally came up with six fuzzy families of approaches to AHS. Then last fall, in October, we had a workshop with about 100 stakeholder representatives. We explained the concept families, and we got some very clear indications from the people attending that we had not adequately defined what these concepts were. In fact, they pointed out that one wasn't even a separate concept. So we changed them. That's not a neat process at all, but we managed to capture what they wanted and folded it in."

So to keep the down-selection process honest, the consortium is actively bringing in stakeholders and interviewing them to assess such points as customer willingness to pay, marketability, deployment, and pricing. Associate participants are a major resource here. Above all, the consortium is trying to avoid the bugaboo that haunts most technological enterprises. "Just because you can do it, doesn't mean you should, or that anyone will want it, or be able to afford it, or be able to use it," a consortium member observes.

The Five Concept Families

  • Independent Vehicle Concept: This concept puts a smart vehicle in the existing infrastructure. In-vehicle technology lets the vehicle operate automatically with on-board sensors and computers. The vehicle can use data from roadside systems but does not depend on infrastructure support.
  • Cooperative Concept: This concept lets smart vehicles communicate with each other, although not with the infrastructure. With on-board radar, vision, and other sensors, these AHS-equipped vehicles will be able to communicate with each other and coordinate their driving operations, thereby achieving best throughput and safety.
  • Infrastructure-Supported Concept: A smart infrastructure can greatly improve the quality of AHS services and better integrate AHS with local transportation networks. This concept envisions automated vehicles in dedicated lanes using global information and two-way communication with the smart infrastructure to support vehicle decision-making and operation.
  • Infrastructure-Assisted Concept: In this concept, the automated roadside system provides inter-vehicle coordination during entry, exit, merging, and emergencies. This concept may provide the greatest throughput benefit; it also may require the greatest civil infrastructure investment.
  • Adaptable Concept: This concept acknowledges the fact that AHS implementation will vary by locality. It envisions the development of a wide range of compatible standards that leave as many of the specific architecture decisions, solutions, and deployment progressions as possible to area stakeholders.

The Investigation of Deployment Feasibility

A comprehensive set of institutional and societal analyses, begun early in the program, is yielding results in several areas. The results of the land use and air quality analyses and other investigations are shaping the guidelines for deployment of AHS with respect to: land use, an assessment of regional air quality improvements resulting from AHS implementation, guidelines for integrating AHS as a new capability into the transportation planning process, recommendations to optimize public/private roles in deployment and operations, assessment of AHS operations and maintenance impacts, recommended liability mitigation strategies, definition of the interaction of future AHS deployment with sustainable development, and a methodology for cost/benefit assessments of AHS concepts.

Investigations planned in the near-term include: a detailed assessment of user demand to provide a thorough assessment of market demand across various users, results of experiments and analysis focused on the optimum role of the human in the system, a preliminary assessment of social equity considerations raised by AHS deployment, and a detailed operational concept for automated bus transit operations with site-specific deployment opportunities.

A key aspect of the AHS concepts evaluation process is the program of site-specific case studies engaging state and local transportation agencies in joint efforts to examine the potential of AHS for their particular needs. These case studies address issues for specific regions, corridors, or users. The issues include the long-range planning processes to assess the viability of AHS (to include automated bus/van transit operations) relative to other transportation alternatives, possible institutional arrangements, potential impact on land use, safety, individual benefits, and overall benefits and costs in transportation productivity. To cover the full range of user groups, initial studies will focus on an urban corridor, a rural corridor, intercity travel, freight operations, and transit operations. Several preliminary case studies of these types will yield results in fiscal year 1997, and more extensive case studies will be initiated.

The Outreach

Outreach plays a critical role in all facets of the AHS project. Newsletters, stakeholder forums, workshops, focus groups, a home page on the World Wide Web (, white papers, press releases, coverage by broadcast and print media, booths at trade shows, and attendance at trade meetings and expositions are all mechanisms by which NAHSC gets its message out to, and solicits input from, its various audiences.

A particularly important outreach mechanism is representation on the Project Management Oversight Committee. Last May, a representative from each stakeholder category was elected to serve on this committee drawn from the pool of associate and outreach participants. This representation lets them bring their agendas to the table at the highest level.

NAHSC is also convening focus groups to determine how well the consortium is communicating its messages and how it can best respond to its audience's concerns. The focus groups have yielded some interesting findings. For example, state and local freeway operators sent strong messages to keep operational and maintenance costs resulting from AHS deployment to a minimum and to provide a clearer picture of the intermediate steps that will take us to future automated highways.

Outreach is a two-way street. Feedback must be solicited continually, and it must be heeded. "We take the core of the project very seriously," explains an NAHSC manager. "It's not only doing the technical work, which is relatively easy, but also trying to integrate societal issues while we're doing the technical work and continuing to build consensus among all the categories of stakeholders. It's an incredible process, but it's working."

Nita Congress is a senior writer and editor with vast experience in preparing a wide variety of informational and technical materials for the federal government. She has served as a technical editor for Public Roads since 1985 and has frequently contributed articles to this magazine. In addition, she has written several FHWA research and development annual reports, and she has documented numerous FHWA-sponsored conferences and workshops. She recently served as senior editor to Vice President Al Gore's Reinventing Government Task Force.