EXECUTIVE SUMMARY

1. INTRODUCTION

2. SVID and SET CONCEPT

3.1 Thomas D. Larson, Consultant: "Overview of SVID Concept —Applications and
      Benefits for the Total Transportation System"
3.2 Douglas W. Harwood, Midwest Research Institute: "SVID Highway Infrastructure
      Perspective"
3.3 Eugene Farber, Ford Motor Company: "Thoughts on SVID from an Auto Industry
      Standpoint"
3.4 Thomas D. Gillespie, University of Michigan Transportation Research Institute:
      "Commercial Vehicle Perspective on SVID"
3.5 R. Wade Allen, Systems Technology, Inc.: "A Human Factors Perspective of
      SVID"
3.6 Lester A. Hoel, University of Virginia: "SVID: Observations, Applications, and
      Alternatives"

4. POTENTIAL APPLICATIONS

6. SUMMARY COMMENTS

REFERENCES

The workshop was a one and one half day gathering of approximately 30 individuals having expertise dealing with vehicles, infrastructure, and highway users/human factors. The workshop was organized by an informal working group operating under the auspices of TRB standing technical committees. Although the SET concept is applicable to the broad transportation system, dealing with all modes, the workshop focused on the highway mode of transportation. Such a focus was determined necessary in order to grasp the implications of applying systems approaches to specific transportation topics.

The workshop format included presentations on foundational principles and the current understanding and perceptions of SVID, followed by opportunities for participant discussion. Participants discussed: 1) the subsystem areas of SVID—vehicle, infrastructure, and highway user/human factors, 2) benefits and drawbacks of and alternatives to SVID, and 3) application of a systems approach to two design areas identified by participants as a result of workshop discussion—productivity (truck size and weight) and safety.

Workshop summary comments are reported based on the participants’ deliberations. Included, among others, are: an acknowledgement of the need for enhanced communications among the infrastructure, vehicle, and user groups; a recognition of the evolutionary development of the SVID concepts and the subsequent SET approaches, yet a call for additional detail regarding the approach, feasibility, and implementation of such concepts; a recognition that the current system works reasonably well, yet noting that improvements are needed in specific areas; the need for a championing organization to carry forward the collaborative efforts; the desire to utilize existing institutional structures rather than creating a new structure and identifying several organizational options; as well as identification of potential high payoff areas that may derive benefits from application of a systems approach to design.

1. INTRODUCTION

The Transportation Research Board conducted the workshop at the request of the Research and Special Programs Administration (RSPA), U.S. Department of Transportation (U.S. DOT). The primary objective of the workshop was to provide input to the U.S. DOT for its use in developing a report on the SVID concept, requested by the U.S. DOT 1998 appropriations legislation. The relevant section of the legislation is included below.

The TRB workshop on SVID was an opportunity to further the dialogue on SVID and, in keeping with the primary objective, to obtain feedback from the transportation community for consideration by the U.S. DOT. The workshop agenda was focused on bringing to the forefront important issues of SVID—in particular concepts presented by its developers in the discussion paper by Stephen C. Roehrig, "Systems Engineering for Transportation (SET): Development of Science Based, Transportation Systems Decision Support Tools." This paper raised the prospect of a broad systems engineering approach to vehicle and infrastructure design.

1.2 U.S. DOT Charge

The charge to the U.S. Department of Transportation is as follows:

Department of Transportation and Related Agencies Appropriations Bill, 1998

"Simultaneous vehicle and infrastructure design (SVID)—The conferees direct the Secretary of Transportation to submit a letter to the House and Senate Committees on Appropriations on the concept of simultaneous vehicle and infrastructure design by January 30, 1998."

1.3 Workshop Overview

The TRB Workshop on a Conceptual Framework for SVID was a one and one half day gathering of approximately 30 individuals having expertise dealing with vehicles, infrastructure, and highway users/human factors. The workshop was held on December 17 and 18, 1997, and was organized by an informal working group operating under the auspices of TRB standing technical committees. The working group consisted of the chairs of the TRB standing Committee on Geometric Design, Committee on Roadside Safety Features, and the Committee on Operational Effects of Geometrics; staff of the American Association of State Highway and Transportation Officials (AASHTO)—representing an AASHTO task force on SVID; liaisons from the three federal agencies—the Federal Highway Administration (FHWA), the National Highway Traffic Safety Administration (NHTSA), and RSPA; and representatives of SVID concept developers.

The concept for simultaneous vehicle and infrastructure design is applicable for all modes of transportation. Notwithstanding the potential for broad application, the working group determined that the highway mode was an appropriately complex arena to discuss advantages and drawbacks of SVID. In light of this decision, the workshop focused on highway transportation including passenger and commercial use.

A resource paper was prepared for workshop participants that summarized 1) recent activities focusing on SVID and cooperative vehicle/infrastructure interface, and 2) research efforts on topics comprising major elements of the SVID concept—particularly in areas of system modelling and simulation and including international research and applications related to vehicle/infrastructure interaction. As preparation for the workshop, participants were sent the resource paper, the U.S. DOT charge (see Section 1.2), the original SVID concept paper written in 1995 by David P. Albright, Alliance for Transportation Research, "Simultaneous Vehicle/Infrastructure Design: A Transportation Systems Issue, A National Science and Technology Challenge," a paper presented at the first invitational SVID workshop written by Carl Miller and M. Pierz, "SVID Issues for Implementation: A Vehicle Perspective," and the TRB Workshop SET concept paper by Roehrig, "Systems Engineering for Transportation" (see Section 2). Full text copies or syntheses of papers are contained in the Appendix.

The TRB workshop consisted of presentations on foundational principles and the current understanding and perceptions of SVID, followed by opportunities for participant discussion. Presentations were made on the total transportation system and from the perspectives of highway infrastructure, vehicle manufacturers (automobiles and heavy vehicles), and highway user/human factors. Following these opening presentations, two additional presentations were given—first the SVID/SET concept by its originators, and secondly observations, applications, and alternatives to the concept. For the remainder of the workshop the format shifted from presentations to facilitated participant discussions. These discussions were conducted in groups of eight to twelve participants. Participants were assigned to groups depending on technical expertise and the discussion topic. Two to three groups met concurrently and discussed in three sessions: 1) the subsystem areas of SVID—vehicle, infrastructure, and highway user/human factors, 2) benefits and drawbacks of and alternatives to SVID, and 3) application of a systems approach to specific design areas. Each discussion group gave summary presentations to the full workshop participant group. Materials summarizing workshop discussion and recording issues deemed important by workshop participants are contained in Sections 4 and 5 of this report. It is important to note that the workshop discussion summaries are not consensus recommendations, but documentation of participants' discussions put forth for consideration by the U.S. DOT in developing its report to Congress. A workshop agenda is included in the Appendix.

1.4 Workshop Participants/Speakers

Participants at the TRB workshop represented the various aspects of SVID, including: individuals from federal and state governments, vehicle manufacturers, related industry groups, users of transportation systems, and researchers. A special effort was made to include individuals who have been involved in previous SVID development work, as well as vehicle and highway design professionals who have not been directly involved, yet who would add important perspectives to the discussions. A participants list is included in the Appendix.

The technical disciplines represented by the participants were as follows:

1) general/comprehensive view

2) SVID concepts/history

3) environmental

4) infrastructure

• geometrics
• roadside safety features
• pavements
• signing, traffic signals/marking
• traffic calming

5) vehicles

• automobiles
• heavy trucks/commercial
• tires and other components

6) safety

7) computer simulation

8) human factors

9) governmental regulations

Definitional/conceptual statements:

Regarding fragmentation of the transportation system—independently optimizing transportation subsystems, "The separation of functions within and among modes results in denial if not removal of responsibility for the negative system effects of transportation products and services. Public and private transportation investments should be based on system performance, rather than optimizing parts of the system then trying to mitigate unanticipated results that are secondary to the subsystem but primary to a sustainable transportation system. ...There is a need to move from system fragmentation to System Engineering for Transportation." (Roehrig, 1997).

Collaborative efforts among vehicle and infrastructure designers and the users of the transportation system to enhance safety and efficiency is a rational and, at first glance, not an unusually complex concept. Even recognizing these facts, putting into practice what makes sense may be quite challenging and has not yet been accomplished. However, incremental steps are being made. Over the recent past the concept of collaborative activity and a systems approach to major transportation efforts has received support and continues to foster interest. As more thought and interchange occurs within the transportation community, refinements in this concept are being made. Early discussions centered on cooperative efforts between highway and commercial vehicle professionals, more recent efforts describe the simultaneous design of vehicle and infrastructure considering the user and community aspects, and during this workshop the Systems Engineering for Transportation (SET) concept was put forth as a candidate approach. Each of these stages represents a milestone in the effort to arrive at a workable process to dramatically change, for the good, the manner in which transportation problems are defined, addressed, and solved.

Some central factors critical to the discussion of SVID are:

1) The concept involves the vehicle, the environment in which the vehicle operates, the infrastructure, the individual (the transportation system user), and the affected community.

2) SVID concepts are being strengthened by the advent of more capable science-based system decision support methods and tools.

3) SVID is an evolving and maturing concept. The domain for its applicability has broadened from only highway vehicles and infrastructure to the full spectrum of the transportation system. Yet for ease in concept discussion, this workshop only considered the highway mode.

4) For highway vehicle/infrastructure both passenger automobile and commercial vehicles are considered in the SVID concept.

5) Steps in the SVID Process (Albright, 1996):

The Systems Engineering for Transportation (SET) approach has emerged as a primary mechanism to enable the leap from vision to application. Roehrig discusses in his paper that a Test Capability is the next step in the SVID development. The paper highlights a number of items for consideration and future action:

(See in Appendix, Stephen C. Roehrig, Sandia National Laboratories, "Systems Engineering for Transportation, Development of Science-Based, Transportation System Decision Support Tools.")

3. KEY POINTS FROM WORKSHOP PRESENTATIONS

This section summarizes the key points from presentations given during the workshop. The SET concept paper by Roehrig is described in Section 2 above as a part of the continuing evolution of the SVID process.

Larson describes SVID as a more rational systems-oriented approach to meeting our transportation needs. He reviewed definitions for SVID from a paper written by David Albright, Alliance for Transportation Research, "SVID: A Transportation Systems Issue, A National Science and Technology Challenge." Using three criteria for SVID project selection set out by Albright, 1) common design interest, 2) potential for mutual economic [an/or other] benefit, and 3) value added for individuals, Larson gives possible areas for applications which frame and clarify the SVID concept and illustrate the many relevant factors that must be integral to any meaningful consideration.

The essential congruency in wheel-load/pavement strength and geometry — Acknowledging the essential congruency, in this process, it does not qualify under the SVID definition, i.e., there has not been a true systems approach where both vehicle and road designers and most importantly the "owners" of these have worked cooperatively to ensure optimum solutions. Efforts continue, nevertheless, the processes here have been marked by inefficiencies, acrimony and divisiveness. Only through constant government intervention, through laws and regulation, has a modicum of rationality been preserved.

Building or breaking community—Social and environmental concerns, at a level largely unrecognized by transportation providers over our history, loom large. There is a common design interest, extending to environmental, architectural, and landscape arenas, and the potential for multiple benefits. SVID provides a framework appropriate to consider the best transportation system of appropriately sized, safe, pollution free, affordable vehicles; streets that provide for access and mobility using minimum space while "calming" traffic and having the geometry and strength to serve service vehicles (for example, very large and heavy garbage trucks) and buses.

An automated highway?—If this concept is to be realized, the vehicle and the roadway must not only be compatible in conventional ways, they must "talk" to each other. We have, at best, a primitive understanding of just what will be required for this "conversation." What we do know is that before automated highways are realized, and have the capabilities to serve autos, trucks and transit vehicles, a more complete explication of impacts and benefits must be articulated. In other words, the net for possible impacts must be cast more widely.

A safer vehicle/highway system—The 45,000 deaths each year on the U.S. highway system is a national health crisis, a national disgrace. We struggle to make progress, but rarely see evidence of a holistic, systems approach. At the top, in the U.S. DOT, responsibility is officially divided by law between the vehicle people, National Highway Traffic Safety Administration (NHTSA), and the roads people, Federal Highway Administration (FHWA). Worse than just a legal division, is the bureaucratic competition and consequent suboptimal solutions forthcoming for our tax dollars. Honest, full application of SVID, with no additional investment of public funds, could, save lives.

Examples from air and water transport—Aircraft capabilities have largely driven airport design. Pavements and runways must have strength for growing wheel loads. Terminals must have carefully coordinated facilities for growing numbers of passengers, by planeload and in total. Unfortunately, historic discipline separations and funding-fueled jealousies have lead to terminals remotely located and poorly served by surface transportation. In addition, ships carrying 6000 standard 20 ft. containers, with 8000 capacity ships as the next target, labor into major ports. They require 50 ft. deep, channels and dock capacity for hours long unloading. Here again the congruency between ship and port has been explicitly recognized. The "land side" requirements for moving these containers is more lately coming into focus.

In closing, Larson recaps several observations from Albright, but focuses on one: "The simplicity of SVID is both its strength and weakness. It is a strength in that any person has the ability to quickly apprehend the concept and its potential value. It is a weakness because simplicity may conceal the complexity of challenge in achieving it."

The vision for SVID is as a simultaneous employment of talents, less conflict among parties, and a systems driven application of the best in technology and management across the several elements of transportation systems; these measures can indeed lead to marked economies. The consequence of this would be an improved adequacy of funds for the provision of transportation access and mobility.

(Excerpted from referenced paper.)

The Harwood paper presents an overview of the needs for Simultaneous Vehicle/Infrastructure Design (SVID) from the highway infrastructure perspective. The paper first discusses the goals of highway infrastructure design, the potential benefits of SVID, and the scope of SVID from a highway design perspective. The paper then identifies the vehicle characteristics of interest to highway designers and how highway engineers typically obtain the vehicle data they need. Highway infrastructure issues related to vehicle design are then discussed to identify, where possible, current applications of SVID or potential future roles for SVID. Finally, the paper identifies some potential topics for future discussion that might be considered for breakout discussions at the workshop.

Goals of highway infrastructure design—Engineers must meet a broad set of goals that define the criteria for operation of the highway facility itself and its place in the community. These goals include:

Potential benefits of SVID:

Scope of SVID—To be successful, SVID must be broader than just what is traditionally understood as highway design. The operation of the existing highway system is as important to efficient highway travel as the design or redesign of highways, and the management of operations is heavily dependent on the understanding of vehicle and traffic characteristics. Both design and operations have policy, planning, and research components that need to consider present and future vehicle characteristics. In addition, SVID clearly needs to address reconstruction and rehabilitation projects, as well as new construction. Finally, a key element missing from the title of SVID is the driver—the scope of SVID should be more clearly defined to formally address highway/driver/vehicle interactions, rather than just highway/vehicle interactions.

Vehicle characteristics of most interest to highway engineers include:

The key highway infrastructure issues that these vehicle characteristics affect are summarized below:

Highway Geometric Design—Vehicle characteristics are reflected in design policies such as the AASHTO Green Book. The Green Book incorporates a set of design vehicles whose dimensions and characteristics are considered explicitly in design. These design vehicles include a passenger car and several types of trucks, buses, and recreational vehicles. Typically, one of the design vehicles is selected as the basis for design of any particular highway project. The specified characteristics of the AASHTO design vehicles include: vehicle height, width, length, overhang (front and rear), axle and hitch point spacings, and turning/offtracking characteristics.

The AASHTO Green Book and other geometric design policies contain many specific design criteria that are based on vehicle characteristics but are not tied to any of the specific design vehicles. Vehicle-related characteristics considered in such design criteria include:

Better geometric design inventory files would be useful in giving both highway and vehicle engineers an overview of current roadway geometrics. Existing geometric data bases such as those in the FHWA Highway Performance Monitoring System (HPMS) and the FHWA Highway Safety Information System (HSIS) provide good data on highway cross section, and some data on highway alignments, but detailed geometric data to address many issues are often lacking.

An example of SVID activity related to highway geometric design that is currently underway is the development of the FHWA Interactive Highway Safety Design Model (IHSDM). The IHSDM will be a computer tool that can be used interactively by highway designers in a Computer-Aided Design (CAD) environment to assess safety as part of the design of a highway facility.

Traffic Operations/Traffic Control—Traffic operations and traffic control evaluation must obviously be based on data about the current or anticipated volumes and types of vehicles on particular highway facilities. Key vehicle characteristics that play a part in traffic operations are vehicle length and acceleration/deceleration capabilities. These characteristics may be considered explicitly through specified criteria in the Manual on Uniform Traffic Control Devices for Streets and Highways or implicitly through sources such as the passenger car equivalents (PCEs) of specific vehicle types in the Highway Capacity Manual. Acceleration and deceleration capabilities are particularly hard to account for properly because of the mix of old and new vehicles in the current vehicle fleet and the highway engineer's lack of familiarity with what the future may hold in vehicle and engine design.

Roadside Design—Key tools in roadside design are:

There appears to be a great opportunity for SVID applications in the roadside design area to assure that roadside hardware designs and vehicle designs are compatible so as to minimize the collision damage to vehicles and the risk of injury to vehicle occupants.

Pavement Design—Design is based on consideration of the numbers and weights of vehicles, particularly trucks, that will be traversing the pavement. The numbers and weights are expressed in terms of the frequency of Equivalent Single-Axle Loads (ESALs), each representing the passage of a single 18,000-lb axle. ESALs are also considered in forecasting future pavement conditions in pavement management systems. The frictional properties of the pavement wearing surface must also be considered in pavement design and pavement rehabilitation.

Structural Design—The design of bridges and other highway structures is also based on the numbers and weights of vehicles using the structure. Structural design must obviously use conservative assumptions and factors of safety to avoid structural failure. However, vehicle characteristics other than vehicle weights do not have a large role in structural design.

Potential Topics for Further Discussion—The highway-related issues that appear to merit further discussion are:

(Excerpted from referenced paper.)

3.3 Eugene Farber, Ford Motor Company: "Thoughts on SVID from an Auto Industry Standpoint"

There are a number of unpredictable external factors that enter into the vehicle perspectives when considering SVID. These factors affect the integration of vehicle/infrastructure/user: oil embargo, greening of America, rise of Japan, end of the Cold War, and Moor's law (every 18 months, for the same relative dollar, computing power doubles).

A number of characteristics of the U.S. passenger car fleet were discussed. Operation features such as anti-lock brakes, air conditioning, remote side mirrors, rear window defoger/defroster and power steering have dramatically increased in the past 20 years. In 1996 the top 10 selling passenger cars had front wheel drive and the top three selling vehicles in the U.S. were trucks (particularly light trucks). Vehicles per licensed driver have experienced an 18 percent increase in the past 15 years, and the miles per vehicle per year have likewise increased at a similar rate. Meanwhile average fuel economy for passenger cars has increased approximately 100 percent, from 14.2 miles per gallon in 1974 to 28.6 miles per gallon in 1995. With all these increases, fatalities although still disturbingly high, have decreased over 20 percent in total and over 50 percent per 100 million vehicle miles. The average cost of an automobile has increased 28 percent in real dollars, perhaps reflecting the greater amount of disposable income within the U.S., as well as the increased sophistication of the automobile design.

Looking into the future there will be little change in general performance or in the basic design elements of the passenger automobile. However, technological advancements will most likely occur such as smart air bags, voice activated controls, collision avoidance, adaptive cruise control and other intelligent transportation systems (ITS) items.

Technological change is not the only area of concern for vehicle design. The policy level will be a productive forum for furthering the SVID concepts. Encouraging greater interaction among vehicle, infrastructure, and driver must have a heightened awareness with policy makers. For example, the Swedish initiative of "Zero Fatalities" within the next 50 years is a policy level initiative that could use SVID concepts to successfully further that goal. These types of goals are possible for the U.S.—safety, congestion, and others of such complex nature.

(Excerpted from referenced presentation.)

3.4 Thomas D. Gillespie, University of Michigan Transportation Research Institute: "Commercial Vehicle Perspective on SVID"

It has been said that highway engineers design trucks through the weights and dimensions regulated by road use laws. While the vehicle owner has some latitude in tailoring the vehicle to its intended mission and to achievement of maximum productivity, the vehicle must be designed to road use formulae intended by law to preserve the infrastructure. Considering this dynamic may have originated from very early times, the advent of SVID calls for a different model. SVID calls for enhanced communication between the highway community and the community of designers and users of trucks. Progress has been made in the recent past as synopsized in the "Highlights and Syntheses of Recent Activities" section of the Appendix. A number of the initiatives recommend bilateral efforts—those involving the highway and the vehicle. Unfortunately, many noteworthy initiatives have been unilateral—the highway community studying trucking and trucking operations to determine how to improve or protect the highway system with perhaps only a cursory involvement from the trucking community . Likewise, there have been few initiatives from the trucking community to improve trucking performance or operations with participation from the highway community.

Cooperation among the public sector and the private sector has some major barriers. For example, competition in the private sector among truck manufacturers makes cooperative involvement with the public sector very difficult. There is a place for industry groups, such as the Society of Automotive Engineers (SAE) and the Truck Manufacturers Association, to bridge the gap to assist with competition- related issues.

Areas for cooperation among the highway and trucking communities are as follows:

Pavement and Bridge Life—Such studies as the AASHO Road Tests conducted in the late 1950s, the recent DIVINE Project (See Appendix "Highlights and Synopses of Recent Activities"), and other research have attempted to establish some empirical relationships between vehicle properties and pavement performance. Although industry participation is sometimes obtained for these types of programs, it tends to be supportive of the research efforts without evidence that the findings directly affect industry practice. Industry is interested in productivity improvements, and any results that adversely affect productivity will tend to decrease motivation to apply research results. Moreover, reports of findings are rarely circulated among the industry audiences.

Intersection Geometry—Offtracking and swept path dimensions are the metrics relevant to turning performance at intersections. Highway engineers have routinely attempted to take these concerns into account via turning templates for various vehicle combinations. However, studies that have produced some rational responses to these issues have largely been collaborations between government and academia without direct industry input. Meanwhile, the industry interest tends to be based on a political level to obtain access to more productive vehicles. Cooperation and collaboration will bring these agendas more closely together.

Vision and Sight Distance—Truck operations on highways are affected by the low performance of these vehicles and the difference in driver position that relate to truck driver vision issues. More collaboration between highway designers and truck operators would be beneficial. Sight distance design, traffic signal timing, signage and sign illumination are areas in which improvements could be made through greater interaction between the highway and trucking communities.

Noise Control—This is an example where increased cooperation among highway and trucking interests and the public would be productive. Noise barriers along heavily used truck routes shield residential areas from noise. However, highway tractors have high-mounted exhaust stacks broadcasting noise from 12 to 13 feet above the pavement prompting higher and more costly noise barriers. Truck manufacturers respond to the needs of the buyers, while public expense mounts for noise barrier construction.

The vision of building collaborative arrangements under SVID must find solutions to several impediments:

1) The highway community is relatively homogeneous and comprised of public agencies. Thus, cooperation among these agencies is non-threatening.

2) The trucking community is private sector and highly competitive. Each operator is trying to be more productive and efficient in order to gain competitive advantage.

3) The trucking community is quite diverse and addresses a broad range of transport missions. Trucks are designed by manufacturers trying to appeal to consumers.

4) To obtain participation in any cooperative efforts, there must be incentives that are meaningful to the trucking community.

For SVID to succeed it will be necessary to carefully analyze and consider the motivations of trucking interests and to seek ways to offer advantages that will improve competitiveness. A model from the World Bank may be appropriate: emphasizing total road user costs coupled with a philosophy to maximize transportation while minimizing costs. Goals other than preserving the infrastructure must also be examined—striving to find goals that are meaningful to the trucking industry are important. Safety is such a goal, and is of interest to truck manufacturers, owners, and operators.

(Excerpted from referenced paper.)

Human factors considerations are a key element to system design. The human/machine interface is a critical component in improving system safety and performance. The inclusion of sound human factors principles during the early stages of design can provide safety benefits from systems which are primarily designed for other purposes. Similarly, failure to apply human factors principles or unintentional misapplication, can degrade the level of safety. Including human factors considerations in the SVID design process provides potential for increased safety and enhanced system performance.

Overall design objectives from a human factors perspective involve maximizing both the performance and safety of transportation systems. In terms of performance, objectives focus on lower congestion and pollution, improved ride, minimized deterioration of highway components, and economy and efficiency of operations. From a human factors perspective, these systems performance improvements should translate into an increased system operator/user satisfaction due to improvements in travel time and mobility, reduction in hazards, and less frustration with system operation.

— displays (format and content)

— controls (configuration and layout)

— operator workload/distraction/attentional demands

— biodynamics and occupant kinematics

— system integration (control/display, warnings, etc.)

— learnability, useability, maintainability

— human operator population

Safety and human factors design requirements must be substantially dealt with during the SVID design process. Often these considerations are relegated to design reviews, or even worse at the product testing stage, which is far too late in the design cycle to adequately account for safety and human factors concerns. Stages in the design process are identified below and human factors issues are summarized for each stage.

Conceptual Design—This is the stage where requirement specifications are developed. The operator/user population should be identified, and tasks and interfaces should be defined. The overall functional capability of the operator/user/system should be defined, and functions allocated between humans and machines.

Design Development Research—Questions regarding human/machine interfaces, information processing, task cognitive and response time requirements, and the consequences of human error and system failure enter here.

Preliminary Design—Tradeoffs between hardware and software are decided at this point, and other details of design emerge.

Prototype Development and Testing—This is the stage where a working prototype allows for further safety and human factors analysis. Human factors testing should be carried out to evaluate human/machine interface, training, useability, and maintainability issues.

Production Engineering—Wherein final safety and human factors reviews are conducted.

There are typical evaluation methods and approaches used for design evaluation: analysis and computer modeling, laboratory testing, in-situ evaluation, and post deployment evaluation. These are evaluation methods that will be important to incorporate into the SVID process. Some analysis and simulation may be needed to establish and refine requirements and specifications. Prototype hardware and software should be evaluated for useability, training requirements and human/machine interface characteristics at the earliest opportunity in the design cycle. Finally, prototypes and production engineering models must be evaluated to verify and validate software and to establish safety-critical reliability.

The SVID process is critical in dealing with the design of increasingly complicated vehicle/infrastructure systems. These systems include traditional concerns as well as the advent of ITS. The system design process must embrace human factors principles in properly accounting for the human element in transportation systems.

(Excerpted from referenced paper.)

3.6 Lester A. Hoel, University of Virginia: "SVID: Observations, Applications, and Alternatives"

The task of this paper was to provide observations about the SVID concept, to consider applications where this methodology might be an improvement over current practice and to discuss possible institutional arrangements that would assure its implementation. The SVID process begins with the same premise as described for the highway design process, in that it seeks to observe the inter-relationships between the vehicle and infrastructure performance and the behavior of the transportation user. Moreover, the SVID process goes beyond present practice which compartmentalizes responsibilities for vehicle and infrastructure design. It calls for the creation of a new design paradigm that incorporates both functions simultaneously.

The concept of SVID is an appealing one and its timing is propitious, coming at an opportune moment coincident with developments in telecommunications, advances in the understanding of human responses to transportation stimulus, and advances in vehicle and infrastructure design techniques. As we have heard, a wide variety of problems are potential candidates that could benefit from the SVID process that involve the evaluation of alternative designs from the perspective of safety, community impact and the environment. Not every transportation problem will require SVID, and some application areas will result in higher payoffs than others.

General issues for consideration:

1) What appears to be lacking in the various papers and reports about SVID are specific examples that illustrate the SVID process. Without some form of validation that produces additional details regarding how SVID would actually function, acceptance of the concept becomes a "leap of faith." Absent a set of case studies that result in an appraisal of the concept that includes costs, benefits, advantages and disadvantages, the claims made for the process and the promised results are based on assumptions, speculation, promises, and best guesses. The input from other "stakeholders" such as the design community, the states, FHWA, and universities will be essential. These observations are intended to strengthen a concept that appears to be visionary. Exploration into the issues regarding implementation and results to be achieved provide the means to certify the validity of the process and identify areas of application.

2) Design processes must change. Over time SVID would replace outmoded methods, thus establishing a new standard design methodology. Under this scenario the key issue will be how to transfer this new design technology so that it is integrated into current practice. Highway design occurs at many levels and is as decentralized as the industry in general, with design specialists working for state DOTs, cities, counties, consulting firms, and federal agencies.

3) Application of SVID will prompt institutional changes. The transfer of the SVID process into practice will require agency employee education and training regarding appropriate classes of design problems and the computer tools for evaluating alternatives. Other institutional issues may arise including liability, proprietary use of design tools, and relationship to highway design standards.

A strong case has been made for the use of system engineering in the design, operations and maintenance of transportation facilities. The concern with the SET Test Capability vision is with its scope and complexity. Three questions are posed; they are: Why do it at all? Why do it now? Why do it this way? Other items for consideration are:

If not SVID, then what? It appears that a strong case has been made for SVID. Criteria have been made for its application, and potential projects have been identified. The option of simultaneously considering design features of vehicles and highway elements under a wide range of human factor scenarios is indeed appealing. The potential to improve upon current practice appears strong. There also appears to be a willingness on the part of the public and private sector to partner in this effort.

We are still in the infancy of this concept and thus guidance, direction, and case study examples of good practice are needed. Fortunately, considerable talent and expertise exists nationwide to address the issue of implementation of SVID demonstration projects and the reeducation of transportation designers. There is no compelling reason why one organization or group should have a preemptive claim to develop the concept. To succeed, the SVID program effort will require the cooperative effort of many parties as well as financial support.

Among the organizational options that could implement an SVID process are the following. These and others would need further development.

1) A university-based model, that has many precedents, would be the creation of a Center for Simultaneous Vehicle and Infrastructure Design.

2) AASHTO has undertaken "pooled funded" projects that address common problems (the NCHRP program or the Strategic Highway Research Program are other examples).

3) The U.S. Department of Transportation—each modal administration—has research facilities that could be engaged in the SVID process. These efforts could be spearheaded through the Volpe National Transportation Systems Center (a unit within RSPA).

4) Various consortia could be formed for SVID studies. These might include the U.S. DOT, states (AASHTO), and industry, or other organizational formats could be envisioned that involve the support of manufacturers associations and professional groups such as the SAE.

5) A "think tank" ( such as the MITRE Corporation) could be contracted to coordinate and develop the SVID process.

There are many organizations and individuals that might come forward in response to an SVID program. These include universities, private-sector "think tanks," consultants, and industry. The potential for national participation suggests that in addition to validating the SVID concept, this workshop could address alternate mechanisms for its implementation that will produce the results desired by harnessing the best talents that this nation has to offer.

(Excerpted from referenced paper.)

Potential applications for SVID and for demonstration of a SET Test Capability were brought forth in the discussion by participants in breakout groups. The discussion topics began with a more general focus that narrowed as the discussions proceeded. After two series of breakout discussions, two topics emerged as being worthy of consideration for the third and final series of discussions. These deliberations focused on application of a systems approach to the topics identified : 1) productivity—truck size and weight, and 2) safety. This section summarizes the discussions from each of the three series of breakouts. The first begins by identifying aspects of infrastructure, vehicle, and users that would benefit from a systems approach. The second series of discussion focuses further on the benefits and drawbacks derived from establishing a systems approach to infrastructure and vehicle design and gives comments on the SET Test Capability concept. Lastly, the section provides information regarding application of a systems approach to two specific issues of importance to the infrastructure, vehicle, user communities.

Initial discussions focused on infrastructure, vehicles, and highway user/human factors. Each group discussion was guided by three questions which follow along with the discussion group summary statements.

Question 1: Which specific aspects of highway design and operations would benefit from a systems evaluation approach involving the highway, vehicle, user, and communities?

Question 2: Which of the items in question 1 would likely have the greatest payoff, i.e., which represent the greatest need for greater interface?

Question 3: Which are the best candidates for tomorrow's discussion?

The group identified the following items as primary areas for potentially deriving benefits from application of SVID concepts and as items worthy of further discussion by the group:

Other items discussed were:

The vehicles discussion group identified high payoff areas that could benefit from application of a systems approach. The group presented aspects within the vehicle and highway domains that would be likely candidates for further examination. The group did not have time to concentrate on the user aspects of these high payoff areas. Areas are listed in priority order.

4.1.3 Highway User/Human Factor Areas Benefiting from a Systems Approach

The group focused on applications after the SVID Planning Matrix (See Appendix—Miller and Pierz) was presented as a suggested means of organizing thoughts on the topic. Several candidate applications identified by the group are:

Potential Payoffs

In an attempt to determine the benefits that might be realized from the implementation of the SVID approach, various advantages were cited. These included:

Five topics were identified as areas where increased interaction would be important. These included:

Pavement surface/driver/vehicle interaction— The understanding of the dynamic effects of heavy vehicle suspension systems suggests that highway design place greater emphasis on "infrastructure smoothing." This should include pavement roughness, bridge approaches, pavement joints, and vertical profile. Improvements in this area would lead to better ride quality, reduced driver fatigue, and improved vehicle stability. Fixes could be implemented relative to the infrastructure, the nature and functioning of vehicle suspension systems, or enhancement of driver capabilities. These system considerations need to be embodied in pavement design guidelines.

Design Guidelines for Safety—There is a need for a better means of assessing the safety impact that results from vehicle and infrastructure designs. A systems approach in a set of design guidelines could provide a means to assess the safety impacts of introducing new vehicles, changing speed policies, and/or designing highway improvements. The guidelines could include more complex criteria for the design of systems, e.g., use of a user vision window that would reflect the range of driver eye heights and the visibility provided by the vehicle.

Traffic Management Systems—These systems are highly dependent upon effective response by the users for navigation, compliance to traffic controls, recognition of hazards, and other aspects. Guidelines could be developed for improved street design that would lead to traffic calming and maximized flow by better understanding driver needs and response. The systems approach would lead to more effective user interface designs for ITS technologies.

Dynamic Preventative Maintenance—Improved systems are necessary to translate information derived from various types of probes into strategies that will rationally extend pavement life. Systems like PONTIS (a tool for bridge management) show that there has been progress in considering different logistics methods in infrastructure maintenance. It is not clear how information derived from efforts like the DIVINE project can be integrated effectively. Transportation facilities tend to be operated over relatively long cycles. Part of the solution is to use stronger materials and carefully control the quality of construction. These clearly are candidates for a systems approach. It was suggested that the Golabi concept using Markov processes might represent a model for a systems based approach.

Substitution for Travel—This topic was raised, but not discussed.

The criteria proposed by the Alliance for Transportation Research (ATR) for identifying SVID opportunities (e.g., common design interest, mutual benefit, value added) were used in an attempt to determine candidate applications with the highest potential. Pavement maintenance and traffic management were identified as two very important opportunities.

The discussion continued with breakout groups addressing a more focused aspect of the SVID concept and the SET Test Capability as described in the Roehrig paper.

Questions addressed by the participants were:

Question 1: What are your impressions of the potential benefits to be derived from establishing some type of systems evaluation approach for highway and vehicle design?

Questions 2 and 3: What are the perceived benefits and drawbacks?

Question 4: What are your impressions of the Sandia National Laboratories suggested approach (Roehrig paper)? Benefits? Strengths? Drawbacks? Next Steps?

Question 5: Are there promising alternative or complementary approaches? Benefits? Strengths? Drawbacks? Next Steps?

General points brought out in the discussion groups are as follows:

The following items were identified by the groups as potential benefits from using a systems approach to vehicle/infrastructure design:

—can evaluate prior to legislation/regulation
—can form consensus.

Several drawbacks to a systems approach were noted. These are:

Participants comments regarding the SET Test Capability approach are summarized as follows:

If implementation of the system approach were to be pursued, the next steps would involve:

1. Selecting a focal point. It was noted that recent efforts to develop strategic plans in the safety area represent possible focal points that have considerable background. These include the Strategic Plan for Highway Safety prepared by the AASHTO Committee on Highway Traffic Safety and the Strategic Plan for Improving Roadside Safety prepared under NCHRP Project 17-13.

2. It is believed that some group made up of knowledgeable persons from varying disciplines and organizations should be charged with identifying the issues that need attention. For example, the AASHTO Joint Task Force on the Compatibility of Vehicles and Highway Designs will involve persons from the DOTs, SAE, AASHTO, the trucking industry, and other groups. They could identify current incompatibilities and take on the role of monitoring changes in the system to avoid serious new incompatibilities.

3. The need for a new organization has not been adequately documented. Existing "centers," programs, or organizations may be better situated to investigate specific issues. The effectiveness of the concept would require a structure that would support the interaction across the various aspects at the highest levels of government. For example, FHWA and NHTSA would need to be functionally more integrated.

4. The identification of a "champion" would greatly facilitate the implementation of the concept. Coalitions of organizations might also be useful.

5. There is a need to increase the dialogue and communications between the various groups of designers. This could be accomplished in many ways including joint meetings, the sharing of databases and information resources, or the inclusion of liaison representatives between professional organizations.

6. Things change, so it is critical that "modularity" be built into the approach to allow incremental updates or modification to be easily incorporated.

As a result of the two prior series of discussions, the participants focused on two major issues to use as example topics for a systems approach to design. These topics were productivity (truck size and weight) and safety. Workshop participants were asked to consider the following items:

The below sections summarize participants discussions on the topics.

An attempt was made to scope out the extent of the truck size and weight issues and see where SVID concepts could apply. This is an extremely diverse problem with myriad aspects, yet it seemed that most aspects could be classified into two areas: (1) highway/bridge/engineering issues, and (2) political/safety/environmental issues.

Focus areas for a systems approach in the truck size and weight arena were identified as follows. Items are listed in order of importance.

Stakeholders/Institutions that would be involved in a systems approach to truck size and weight design issues were identified as:

There was some concern regarding the difficulty of presenting a common front—a consensus on direction and goals. If this can be done, then the following would be reasonable next steps.

1. Collect and disseminate current knowledge. Identify institutions that could collect and package appropriate data, identify data gaps, and identify areas needing research. Elements that would be focus areas for data dissemination are a) vehicle/highway interaction and b) process information—how to work through the systems approach.

2. Adopt and continue the process already established via organizational efforts such as the past Motor Vehicle Manufacturers Association meetings.

3. Identify the next champion—a champion to carry the process forward will be essential.

4. Identify what makes the most sense as far as a vehicle that would be best configured to haul goods on America's highways—given safety, environmental, productivity, and other constraints.

5. Convene a group (perhaps the newly created highway/vehicle interaction group being organized by AASHTO) that will identify the specific steps needed to progress.

6. Focus on areas involving interaction between highway designers and truckers that have an impact and are achievable.

7. Make sure that there are appropriate efforts spent in scoping the problem for SVID application. The case may be that while dealing with a broad issue, addressing one aspect at a time may be the most feasible approach.

Other points of interest identified were:

The group was asked to consider safety, the stated top priority of the Secretary of Transportation. It was noted that such pronouncements were not rare—Sweden recently announced their intent to pursue "Vision Zero" to eliminate all traffic fatalities. The group leader initiated the discussions with the premise that the objective of the systems approach would be to maximize safety. This could be accomplished by reducing the number and rate of crashes, fatalities, injuries and amount of property damage. Achieving the goal would be subject to the constraints of minimum impact on productivity and the environment.

The discussions about the feasibility of this systems approach noted:

In an effort to focus the discussions on a systems approach to safety, the elements of the AASHTO Strategic Plan for Highway Safety were reviewed. It was noted that six areas were targeted—namely:

Under these six areas, twenty-two high priority action areas (and associated strategies) were outlined (See Appendix for a list of these areas). These provided a glimpse of the means currently believed to offer the greatest promise for reducing fatalities by 5000 to 7000 per year over the near future.

It was noted that the Highway Safety Improvement Programs (SHIP), promulgated in the early 1980s represented a systems approach. The SHIP provided detailed procedures and information to support a ten-step process for use by DOTs. The ten steps included:

2) Use data to identify high accident locations.

3) Review the individual highway accident locations to initiate the search for solutions to accident problems.

4) Conduct detailed analysis of accident data to determine the possible causes of accidents.

5) Undertake engineering studies to ascertain the probable causes of accidents.

6) Determine safety deficiencies and identify possible countermeasures.

7) Assess the alternative countermeasures for a high accident location to determine cost effective treatments.

8) Prioritize projects under the constraints of available resources.

9) Implement projects and ascertain that they are constructed properly.

10) Evaluate projects and programs in the after period to determine effectiveness.

Most states have implemented such a system, although the features of the systems differ considerably. It was noted that the Safety Management Systems (SMS) promoted under ISTEA technically expanded this approach to more broadly embrace safety. It subsequently offered less process detail for the approach. The broader SMS approach incorporates greater emphasis on driver and vehicle considerations to achieve safety goals. It was noted that SVID potentially offered the means to weigh safety goals against environmental, productivity, capacity, and other objectives.

The comprehensive approach to addressing safety concerns will necessitate the involvement of many entities, including:

These groups and others need to forge coalitions to share the responsibility of solving safety problems.

Although most agencies have systematic approaches to addressing safety, comprehensive, accurate, and detailed data are needed. There have been successful efforts to identify high accident locations, measure the effectiveness of some safety improvements, and assess driver and vehicle enhancements. Often, however, the data limits the search for answers to important safety questions. It was noted, for example, that in most cases locational accuracy does not permit the correlation of crash events with the roadside objects struck. Or, it has not been possible to define the safety impacts of combinations of vertical and horizontal alignment elements. Where relationships have been developed, extensive manual data mining efforts have been necessary. Efforts to standardize data (e.g., CADRE) and link it to other data sets (e.g., pavement condition, or medical records—CODES) have been limited. The top-down SVID approach might be useful in establishing the importance of data elements and to lay the foundation for effective sharing of data resources.

The group proceeded to talk about how a systems approach for safety might be implemented. The steps included:

1) Begin with an established plan that cuts across the vehicle, driver, and highway elements, such as the recently approved AASHTO Strategic Plan.

2) Build a compelling case for the need to address the problem using information on crash losses.

3) Establish data resources and analysis capabilities for a comprehensive, systematic review of the problem.

4) Set action priorities based upon cost effectiveness analyses.

Even with a legacy of "systems" efforts in safety, it would not be easy to implement a system. The challenges include:

The discussions ended with the recognition of the fact that the systems approach would provide additional information for the other aspects associated with a solution to a problem. These would be weighed in conjunction with economic, capacity, institutional, and political factors. It was also noted that diminishing returns would potentially lead to difficulty in making a positive impact, particularly as volumes increase, traffic fleets change, the driving population ages, and other changes manifest themselves. These challenges are somewhat offset by the current revolution in information systems.