National Academies Press: OpenBook
« Previous: Front Matter
Page 1
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

Executive Summary

Tens of thousands of lives lost and millions of injuries each year on America’s highways; deteriorating bridges and pavements; hours of congestion and delay due to highway construction work zones, crashes, and other incidents; insufficient capacity to meet the needs of a growing population and expanding economy—these critical highway transportation problems demand solutions as we enter the third millennium. In this report a Future Strategic Highway Research Program (F-SHRP) aimed at addressing these problems is outlined.

Purpose

The highway network is the backbone of America’s transportation system, making it possible to meet the mobility and economic needs of communities, regions, and the nation as a whole. Americans use the highway system to make more than 90 percent of passenger trips and move 69 percent of total freight value; highways also accommodate buses, bicycles, and pedestrians. In addition, highways provide vital links among all modes of transportation; thus the influence of their physical and operational condition extends well beyond the impacts experienced directly by highway users.

The problems outlined above are therefore pervasive, with wide-ranging impacts on the nation’s economy and quality of life. The first Strategic Highway Research Program (SHRP), conducted in the late 1980s and early 1990s, focused on a few critical infrastructure and operations problems faced by state transportation agencies. Given the success of SHRP and the pressing need to find solutions for the problems challenging the highway system today, the Congress requested in 1998 that the Transportation Research Board (TRB) “conduct a study to determine the goals, purposes, research agenda and projects, administrative structure, and fiscal needs for a new strategic highway research program.” Accordingly, TRB formed a committee of leaders from the

Page 2
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

public, private, and academic sectors of the highway community to carry out the study that resulted in this report.

Strategic highway problems and promising avenues of research and technology for addressing these problems are identified in this report. Rather than detailed research plans, an overall direction for those who may be charged with developing such plans is provided. As discussed below, the committee recommends that an interim planning stage take place between the publication of this report and the commencement of the research program. In the event that such an interim effort cannot be carried out, it will need to be the first step taken once the research has been funded. This report is intended to keep such a planning effort focused on the identified strategic needs, without unduly constraining researchers and research managers in exploring and developing the most promising research tasks and technologies.

Approach

The F-SHRP committee began its work by articulating an overarching theme to guide the study. This theme is grounded in the fact that everyone is a customer of the highway system in some way. Customers expect high levels of service throughout the economy, and highway transportation is no exception. With this in mind, the committee identified as the theme of the study providing outstanding customer service for the 21st century.

In accordance with the congressional request, the study approach adhered to the SHRP model of a special-purpose, time-constrained research program in which a concentration of resources is used to accelerate progress toward a few high-priority objectives. The committee also decided that its approach to the study should have three characteristics: it should address highway needs from a systems perspective; it should be open to research in nontraditional highway-related areas; and it should explicitly acknowledge the interdependence of highway research and technology programs.

In keeping with the overarching theme of providing outstanding customer service for the 21st century, the committee decided to conduct an extensive outreach process to identify highway needs and research opportunities. Stakeholders representing user groups, the private sector, various interest groups, and universities, as well as federal and local agencies and all state departments of transportation, received letters soliciting their input. Scores of presentations, briefings, and focus group sessions also took place. An interactive website was developed as well to allow for electronic input and provide periodic updates on the progress of the study.

Page 3
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

The outreach process identified hundreds of highway needs and research opportunities. From this vast array of possibilities, the committee had to select a limited number of focus areas for the F-SHRP research, as well as specific topics on which to concentrate the work in each area. In thus defining the scope of the program, the committee was mindful of the pitfalls of trying to do too much and thereby compromising what could be accomplished. Therefore, through a multistage, iterative process, the committee selected a small number of topics that met the following criteria for inclusion in a new, focused, independent research program:

  • Significance of the issue—Each topic addresses a national transportation need and represents a critical issue faced by most, if not all, departments of transportation.

  • Appropriateness for a SHRP-style research program—Each topic requires a concentration of dedicated resources, at a large scale, over several years to accelerate progress toward implementable goals in a relatively short time frame. Each also requires an integrated approach involving coordination among many disciplines and numerous stakeholders.

  • Effectiveness and expected impact of research—For each topic, research and technology hold promise for delivering results that will have a significant impact on highway system performance in ways that matter to customers. These results include increased safety; reduced delay; more effective and quicker highway renewal, yielding longer-lasting, higher-quality facilities; and enhancement of the economy, the environment, and communities.

F-SHRP Strategic Focus Areas and Research Programs

Through the iterative process described above, the committee concluded that F-SHRP should comprise research programs addressing the four strategic focus areas described below.

Renewal: Accelerating the Renewal of America’s Highways

Overall research program goal: To develop a consistent, systematic approach to performing highway renewal that is rapid, causes minimum disruption, and produces long-lived facilities.

Page 4
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

Challenges and Opportunities in Highway Transportation

In meeting customer expectations, the transportation community faces both challenges and opportunities that require new ways of thinking about moving people and goods. The challenges represent a broadening set of performance demands on the highway system, including technical, environmental, economic, safety, social, and political requirements. Population growth, economic expansion, and changing demographics (the aging population, the baby “boomlet,” immigration) characterize the customer base well into the future and necessitate new approaches to the planning, design, and operation of the highway system. Transportation professionals must respond to the new economy (which is global, rapidly changing, and customer-focused), the desire for greater environmental sustainability, a demand for ever-improving quality of life, the public’s expectations for greater involvement in transportation decision making, and the need for technologies and expertise not traditionally associated with highway engineering. Demand for passenger travel and goods movement is expected to increase significantly during the next two decades, even as Americans continue to place a high value on the privacy and flexibility of personal automobile travel. Strict reliability requirements for freight movement, enabled by information and communication technologies, must be met by an increasingly congested highway system. Yet the capacity of the system is not likely to expand as rapidly as demand, so more efficient operation of existing capacity is paramount. At the same time, selected capacity improvements will continue and must be planned, designed, and built to meet customer expectations.

Research and technology advances offer opportunities to address these challenges. For example, human factors research and new data collection technologies can help in better understanding and addressing factors associated with highway safety. Sensors, high-performance materials, and new approaches to construction and contracting can contribute to the renewal of highway infrastructure that supports mobility and the economy. Communication and traffic control technologies can help in operating the existing system more efficiently and more safely. Better economic and environmental models and improved planning and design approaches can make it possible to provide new infrastructure that enhances the economy, safety, and the human and natural environments.

Page 5
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

Background: After decades of constant use, often exceeding facilities’ original design life, much of the highway system is in need of extensive renewal. Because of the indispensable role of these facilities, however, renewal work, in contrast to the construction of new highways, must be performed while the facilities remain in service, introducing significant safety, mobility, and economic concerns. The public demands that this work be done quickly, with as little social and economic disruption as possible, and in such a way as to reduce future interventions to a minimum. The safety, economic, financial, management, environmental, aesthetic, and technological challenges of facing this situation on an individual project are formidable enough. Meeting these challenges on a nationwide scale will require the development of an entirely new way of approaching highway renewal.

Description: Under F-SHRP, a systematic method of analyzing renewal needs and evaluating alternative strategies and technologies will be produced, and the tools highway agencies need to implement a new model of highway renewal will be developed. Research may be performed in such areas as construction methods, materials, and equipment; innovative management and contracting techniques; work zone safety and traffic analysis and techniques; performance measures; and advanced information technologies.

Potential impact:1 The results of this research would translate into user savings in several ways: smoother pavements would lead to reduced vehicle wear and tear and fuel usage; faster rehabilitation would mean less restriction of access to commercial and residential areas; and rapid, less-disruptive renewal techniques would reduce delay due to work zones. The reduced delay would be achieved not only during renewal activities, as a consequence of better management of work zones, but also over the life of facilities through the use of long-lived materials and methods. In a study of 68 urban areas, the cost of delay to highway users was estimated at about $78 billion in 1999. About 54 percent of this delay was due to nonrecurring incidents, such as construction work, disabled vehicles, and crashes. If implementation of the results of this proposed research, together with the results of the travel

1

The estimates of potential impact used in this executive summary and throughout the report are intended to serve as quantitative economic indicators of the extent of the problems addressed by the proposed research and, correspondingly, the magnitude of potential benefits associated with even small improvements resulting from the research. The estimates are not intended to imply that these are the only or the most important potential benefits of the research, nor are they a claim that a particular order of benefit will be achieved. More precise estimates of the specific types and magnitude of benefits to be derived from applying the results of the proposed research can be derived once specific implementable products of the research have been identified.

Page 6
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

time reliability research described below, reduced such incident-related delay in these urban areas by just 5 percent, the result would be annual savings of about $2.1 billion.

Safety: Making a Significant Improvement in Highway Safety

Overall research program goal: To prevent or reduce the severity of highway crashes through more accurate knowledge of crash factors and of the cost-effectiveness of selected countermeasures in addressing these factors.

Background: While providing indispensable service, highway travel also exacts a high cost in terms of fatalities, injuries, and property damage. Tremendous progress has been made in highway safety during the last several decades, but increases in vehicle-miles traveled threaten to drive up the absolute numbers of fatalities and injuries even as fatality and injury rates fall. Current safety practices and incremental improvements, as important as they are, are not sufficient to break through the safety impasse. To make a significant improvement in highway safety, it is necessary first to develop a much more fundamental understanding of the factors contributing to crashes and the cost-effectiveness of crash countermeasures. A number of advanced technologies make it possible to gather new and more accurate data from which this understanding can be gained.

Description: Under F-SHRP, a combination of traditional crash analysis methods and advanced data collection technologies will be used to understand the importance of various factors in highway crashes and to assess the cost-effectiveness of existing crash countermeasures.

Potential impact: Application of more fundamental knowledge of crash factors and the effectiveness of countermeasures could lead to sizable reductions in deaths and injuries, making it possible to outstrip the anticipated growth in vehicle-miles traveled. Every 1 percent improvement in highway safety resulting from application of the results of this research would mean more than 400 lives saved, 30,000 injuries averted, and $1.8 billion in economic costs avoided annually.

Reliability: Providing a Highway System with Reliable Travel Times

Overall research program goal: To provide highway users with reliable travel times by preventing and reducing the impact of nonrecurring incidents.

Background: As noted above, dependence on the highway system to help Americans achieve a wide variety of business, personal, and professional goals has led to a significant increase in vehicle-miles traveled, while capacity

Page 7
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

increases have remained quite small. The result has been increased congestion and delay. Moreover, such a heavily used highway system is more susceptible to unforeseen variations in travel time due to nonrecurring incidents such as crashes, disabled vehicles, construction work zones, hazardous materials spills, and special events. At the same time, users have become more sensitive to such unforeseen variations in travel time, making highway system reliability a paramount customer need.

Description: Under F-SHRP, strategies and tactics for reducing the impacts of particular types of nonrecurring incidents will be developed. This will be accomplished by studying the likelihood of occurrence of such incidents, the impacts on users, and associated customer expectations, and by applying the many tools and technologies available for managing and responding to highway incidents.

Potential impact: More reliable travel times would mean reductions in unexpected delay, which would in turn translate into significant user savings. As noted above, if implementation of the results of this research in combination with those of the proposed renewal research reduced incident-related delay in 68 urban areas by just 5 percent, the result would be annual savings of about $2.1 billion.

Capacity: Providing Highway Capacity in Support of the Nation’s Economic, Environmental, and Social Goals

Overall research program goal: To develop approaches and tools for systematically integrating environmental, economic, and community requirements into the analysis, planning, and design of new highway capacity.

Background: The existing highway system is straining to handle the current demand in many locations. Given the anticipated growth in vehicle-miles traveled, selected additions to highway capacity are warranted. During the decades spent building and operating the Interstate highway system, much was learned about the complex set of relationships between highways and the economy, communities, and the environment, and much remains to be learned. Any effort to provide new highway capacity must incorporate explicit consideration of these relationships from the earliest planning and design stages so the highway system will simultaneously contribute to national goals in the areas of safety, mobility, productivity, and environment.

Description: Under F-SHRP, an integrated, systems-oriented approach to highway development will be formulated that encompasses engineering, economic, environmental, social, and aesthetic considerations and uses

Page 8
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

appropriate tools and technologies to integrate these considerations in a systematic way throughout the highway development process.

Potential impact: The principal impact of this research is expected to be the provision of new capacity where it is needed, along with all the economic and quality-of-life benefits associated with that capacity, in a way that responds to the full range of customer requirements: highways that are aesthetically pleasing, enhance historical and community values, and contribute to a healthier economy and environment. These types of benefits are difficult to quantify. However, one set of estimates for selected environmental impacts—the costs of road dust, highway runoff, and road noise—indicates that a 5 percent reduction in these costs due to more environmentally sensitive designs would translate to savings of approximately $180 million per year.

Recommendations

Research Program

Recommendation 1: A Future Strategic Highway Research Program should be established.

Given the significant needs and problem areas identified through the outreach process conducted for this study, the opportunities to address these needs through research and technology, and the limited ability of existing programs to exploit these opportunities, the F-SHRP committee concludes that a large-scale, special-purpose, time-constrained research program, modeled after the first SHRP, is justified if the highway system is to meet its customers’ demands over the next several decades. The research conducted under F-SHRP should be focused in the four areas described above.

Administration and Funding

Recommendation 2: The administrative structure of F-SHRP should meet the following criteria: (a) it should possess essential quality control mechanisms (including open solicitation and merit-based selection of research proposals, appropriate review procedures during the conduct of research, and mechanisms for redirecting research as needed on the basis of results); (b) it should have the characteristics required to carry out a large contract research program (including appropriate management, administra-

Page 9
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

tive, and contract support capabilities and the ability to attract and retain talented staff and other resources); (c) it should have focused core staff and secure funding over the program’s time frame (including a reasonably predictable budget that can be managed on a multiyear, program basis, not subject to annual programming decisions or competition with other research priorities); and (d) it should have the flexibility to institute stakeholder governance mechanisms at both the executive, overall program level and the technical, component program level.

The choice of administrative structure should be made during the interim work stage (see Recommendation 5). The details of the mechanisms to be used to meet the above four criteria should be developed during the interim stage as well. The organizational design should address the fundamental aspects of the F-SHRP philosophy: it should support a customer orientation, a systems approach to research, the incorporation of nontraditional research, and coordination with existing highway (and other appropriate) research and technology programs. The committee notes that the National Research Council meets these criteria and successfully administered the first SHRP.

Recommendation 3: The same funding mechanism used for SHRP is recommended for F-SHRP: a takedown of 0.25 percent of the federal-aid highway funds apportioned under the next surface transportation authorizing legislation.

On the basis of the federal-aid highway funding levels of the Transportation Equity Act for the 21st Century and an assumed reauthorization period of 6 years, this recommended funding mechanism can be expected to produce approximately $450 million to $500 million. Given the relative scope and complexity of the required activities, the distribution of funding among the four research areas should be approximately 25 percent for the infrastructure renewal research; 40 percent for the safety research; 20 percent for the travel time reliability research; and 15 percent for the research on tools for providing new capacity in an environmentally, economically, and socially responsive manner. During the interim planning stage, detailed cost estimates should be developed and the total funding requirement, distribution, and percentage takedown modified as necessary.

Page 10
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

Implementation

Recommendation 4: F-SHRP should address the need for implementation of program results from the initial planning stages throughout the management and conduct of the program.

Recommendation 4a: A determination should be made as early as possible regarding where the long-term responsibility for coordination and facilitation of implementation will lie.

Recommendation 4b: A portion of the research funding should be devoted to implementation-related activities appropriate to the research stage; additional funding for full-scale implementation activities will be required once the research program has been completed.

Interim Work

Recommendation 5: A strategic direction for F-SHRP is provided in this report; additional detailed planning is necessary before the research can be carried out. The American Association of State Highway and Transportation Officials and the Federal Highway Administration should consider funding and overseeing the development of detailed research work plans during the period immediately preceding initiation of the research program proper (which is assumed to take place at the beginning of the next surface transportation authorization period).

This interim work should include extensive outreach, a broad range of technical expertise appropriate to each research program, and review of relevant international efforts.

Page 11
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

Characteristics of a Future Strategic Highway Research Program

The committee has identified various criteria and characteristics to help define different aspects of F-SHRP: the four strategic focus areas, specific research programs, and the overall program’s administrative structure. Taken together, the following characteristics describe what F-SHRP should look like and provide a guide for further development of the program:

  • Focused on a few topics of national significance for which a research program of critical mass and continuity is expected to achieve breakthrough impacts in highway practice

  • Time-constrained

  • Driven by stakeholders at the highest management and technical levels

  • Complementary to and interdependent with other highway research and technology programs

  • Customer service–oriented

  • Systems-oriented

  • Open to research in nontraditional highway-related areas

  • Implementation-oriented from the research planning stages through adoption of research results

Page 12
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×

This page intially left blank

Page 1
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 1
Page 2
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 2
Page 3
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 3
Page 4
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 4
Page 5
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 5
Page 6
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 6
Page 7
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 7
Page 8
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 8
Page 9
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 9
Page 10
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 10
Page 11
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 11
Page 12
Suggested Citation:"Executive Summary." Transportation Research Board. 2001. Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260. Washington, DC: The National Academies Press. doi: 10.17226/10223.
×
Page 12
Next: 1 Introduction »
Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life -- Special Report 260 Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB Special Report 260 - Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life examines the goals, research agenda, administrative structure, and administrative needs for a new strategic highway research program. After extensive outreach to the highway community, the committee recommended the establishment of a Future Strategic Highway Research Program (F-SHRP). F-SHRP would comprise four research program areas: accelerating the renewal of America's highways; making a significant improvement in highway safety; providing a highway system with reliable travel times; and providing highway capacity in support of the nation's economic, environmental, and social goals.

The committee recommended that F-SHRP be administered by a credible, independent organization capable of managing a large-scale contract research program in a manner that would ensure the highest-quality research. The initial SHRP program was managed by the National Academies for just these reasons. The committee recommended that F-SHRP be funded at $75 million per year through a 0.25 percent takedown of federal-aid highway funds apportioned under the next surface transportation legislation. As recommended by the committee, the American Association of State Highway and Transportation Officials (AASHTO) has funded the development of detailed research program plans. These plans will be implemented if F-SHRP is authorized.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!