National Academies Press: OpenBook

Resilience Primer for Transportation Executives (2021)

Chapter: Chapter 3 - How to Incorporate Resilience in Your Agency

« Previous: Chapter 2 - The CEO Role in Resilience
Page 13
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 13
Page 14
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 14
Page 15
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 15
Page 16
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 16
Page 17
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 17
Page 18
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 18
Page 19
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 19
Page 20
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 20
Page 21
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 21
Page 22
Suggested Citation:"Chapter 3 - How to Incorporate Resilience in Your Agency." National Academies of Sciences, Engineering, and Medicine. 2021. Resilience Primer for Transportation Executives. Washington, DC: The National Academies Press. doi: 10.17226/26195.
×
Page 22

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

13   It’s not always about a huge investment. It’s about operating smart. How to Incorporate Resilience in Your Agency Resilience discussions in agencies and communities today mostly focus on mitigation approaches or adaptations and protective measures that can be put in place to save lives and prevent property loss and disruption of daily life. Often, resilience measures can be taken with marginal or no additional costs because they fit into the agency’s life-cycle asset management as well as O&M. Resilience is about flexibility. Decisions made for resilience can mean trying different approaches to ordinary activities. Examples DOTs cite include creating capabilities from the bottom up; encouraging adaptive practices and procedures—especially those aimed at detect- ing problems before potential disruptions—and exploring innovative corrective actions such as transitional infrastructure “no regret” strategies and relocating assets. Resilience is crosscutting. It won’t flourish if assigned to just one area of an agency to develop. Resilience requires cross-departmental effort, such as O&M working with planning and design. As CEO, you can push toward engagement and commitment across all functions in your agency. You can develop across-the-board performance measures and ask each division to develop and commit to resilient programs with performance measures. Resilience is not an independent objective; it’s an objectives multiplier. Natural and human-made events and extreme weather conditions affect safety by heightening the risk of earthquakes, bridge collapse, and commercial or passenger vehicle crashes or train derailments. Resilience measures lessen these risks. Forward-looking models and design standards that establish priorities for resilience don’t eliminate risk but do multiply factors of safety, reliability, and cost savings, especially for projects with life spans of as much as 50 to 100 years. Resilience applies to everyday operational decisions and to materials and maintenance. From asphalt coatings and crack sealing to making the case for operations budgets to your state leadership, steps toward resilience do not have to be all encompassing to be effective. Integrate Resilience Throughout Your Agency Your agency already practices resilience in some dimensions, such as • Taking short- and long-term measures to prevent or mitigate impacts of events, • Responding and recovering more quickly after an event, and • Applying lessons learned from previous events to current practices. Agency resilience needs more than a response focus, which may deter investment in pre- vention, resilience, and long-term sustainability. In addition to emergency practice, your agency can be building resilience into everyday operations. Already you may have supportive practices C H A P T E R 3

14 Resilience Primer for Transportation Executives in standard O&M procedures. You may already include experience from maintenance and operations into your design and construction. To be intentional, deliberate, and systematic, a resilience focus can ground both long-range planning and daily practices. While the emphasis on resilience may vary across program areas, adoption of resilience is most effective when it is integrated throughout all areas of agency business. Functional business areas in transportation agencies can become silos. Figure 1 illustrates how resilience encom- passes all of customer-focused transportation service by enhancing the crosscutting practices of asset management, safety, and sustainability. Appendix C highlights in tabular form what employees may expect from their CEO and what CEOs may expect from their employees across various disciplines. Appendix D provides a short list of additional useful resources geared to CEOs and senior staff. Integrate Resilience into Planning and Programming DOT planning is commonly conducted and captured in short-range operations plans, long- range transportation plans, hazard mitigation plans, and emergency plans. Incorporating resilience in long-term plans acknowledges risk factors and forecasts real risks to the agency’s operations and equipment over time or over the life span of a capital project. • Resilience is a cornerstone in the long-term plan for some DOTs. Resilience doesn’t mean overbuilding, but does mean building in flexibility for changing conditions, environments, We’re good at recovery. Figuring out how to prevent in the first place is the challenge. Source: Adapted from TCRP Web-Only Document 70: Improving the Resilience of Transit Systems Threatened by Natural Disasters, Volume 1: A Guide, Figure 1.1, p. xv. Figure 1. Adoption of resilience is most effective when it is integrated throughout all areas of an agency to provide a customer-focused service.

How to Incorporate Resilience in Your Agency 15   and technological improvements that are current unknowns for the life span of infrastruc- ture projects. • Scenario planning is increasingly being used by transportation planning organizations to help determine policies, strategies, or investments in light of uncontrollable or unknown future conditions. • Scenario planning brings together interagency and intra-agency stakeholders needed to address an issue effectively and helps them make decisions that are robust in a variety of futures. – Work with major users of transportation in your region (medical centers, manufacturers, human services) to develop prioritized strategies for response and recovery. – Work with infrastructure and utility owners and operators in the energy, water and sewer, communications, and other sectors to address interdependencies and develop integrated resilience plans and strategies. – Include private-sector organizations that will contribute to regional recovery (e.g., big box stores, home improvement centers, logistics and distribution centers) in resilience planning. Reach out to the press and in public long-range planning meetings to explain why resilience is critical to the DOT’s continued success. If new materials or technologies are being introduced, use the planning forums to unveil and discuss them with the public. ✔ Encourage wide-ranging staff engagement • The Colorado DOT, in the I-70 Risk and Resilience Pilot, has purposely engaged a wide range of staff—engineering, maintenance, operational, planning, and execu- tive staff—to capture the knowledge of each of these areas and to ensure buy-in across the agency for a proactive approach. ✔ Take design to O&M • The California Department of Transportation (Caltrans) found that resilience has to include long-range planning and O&M working with planning and design as a team effort. ✔ Make sure everybody is involved • In the Illinois DOT at project level, everybody is involved, with the driver being main tenance. Sign-off from maintenance is needed to go forward and the DOT “completes the circle” at the district level. Leverage Asset Management Become aware of the ways you can use your asset management system (including bridge, pavement, facilities, and equipment management systems) to help inform your decision- making. Proficient asset management is the foundation of an effective approach to mitigating vulnerabilities, improving maintenance practices, and, ultimately, extending the life span of your assets. Asset management can also allow you to map out how assets are interconnected and gain an understanding of assets that are most critical to your agency. • Risk-based asset management can help in planning preventive measures, prioritizing main- tenance response, and coordinating recovery efforts across your agency and with third parties. For example, you can incorporate fields to help monitor vulnerabilities (e.g., closures due to flooding) and the effectiveness of adaptations over time, and you can configure the system to provide alerts when vulnerable assets are due for maintenance, repair, or replace- ment. You can require that risk assessments of asset management explicitly include forecasts of weather events and other hazards. Asset management is starting to pay big dividends. It allows focus on what you need to do versus what you want to do.

16 Resilience Primer for Transportation Executives • When agencies produce asset management plans that analyze future risk, it becomes easier to justify the use of the resources needed to build and maintain such assets. • Consider resilience in the prioritization process in asset management. Projects can be scored on the basis of extreme weather and seismic and other vulnerabilities, along with the usual considerations of age, performance, impact on operating costs, ridership, customer comfort, employee welfare, safety, response to regulatory demands, and more. • Asset management systems digitize important elements of information and action, such as operation manuals for temporary countermeasures, procedures for dealing with a large accident or emergency, or maps of which roads deteriorate the fastest. ✔ Develop databases and keep them current • The Vermont DOT developed an online database of every culvert in the state after Hurricane Irene to help plan for improvements and to aid in future events. Maintain- ing up-to-date status and condition in the system provides information for quickly making decisions and taking action. ✔ Overlay projections onto asset data • The Michigan DOT conducted an assessment using a geographic information system (GIS) to overlay climate projections onto asset information from the agency’s exist- ing asset management database to help identify locations and infrastructure that may be at risk. ✔ Use systems to predict, track, and assess • Asset management systems with standardized site codes have been used to track and document predisaster conditions of DOT facilities and impacts of the event or incident. Bridge management systems have been used to predict and assess impacts of disasters on bridges. Incorporate Resilience into Design and Engineering As infrastructure and safety agencies, DOTs are exceptionally positioned to take resilience actions and to develop actual solutions. Mitigation approaches and adaptations are available to assist in increasing the strength or the ability of your system to resist stresses and reduce some of the vulnerabilities. • Seek guidance to improve the design of infrastructure to increase resilience. Many resources available at DOTs identify cost-effective approaches and strategies. • Conduct cost–benefit analyses. Understanding the trade-offs with competing priorities is critical. • Recognize the potential co-benefits of adaptations, such as decreased operating costs or improvements in other performance measures. ✔ Develop asset-specific design guidance • The Port Authority of New York and New Jersey (PANYNJ) has developed guidance that uses an asset-specific approach that takes into account the life expectancy of each asset and the risk of agency-specific events happening during that life span. PANYNJ also examines the need for improving reliability when undertaking major repairs and reconstruction and has documented significant cost savings by doing this. We build and prevent scour issues upfront in bridge design. We design facilities [to seismic standards] to provide transport to key lifeline facilities in a response situation. Lowest cost of ownership drives action.

How to Incorporate Resilience in Your Agency 17   ✔ Incorporate vulnerability in design manual • Florida DOT signs and signals are designed with mast arms along coastal areas instead of strain poles, to be more resilient and withstand hurricane wind loads. The agency is strengthening areas with sea walls and elevating roads where possible to mitigate flooding. The design of its drainage systems is being adjusted along the coastline to allow for more efficient water flow out of flooded areas. The agency is continuing to identify other resilience strategies. ✔ Learn to adapt from events • The Maine DOT, following Superstorm Sandy, increased its design standards for most culverts and some bridge replacements to 500-year storm event levels. As a result, culvert blowouts are becoming a thing of the past, annual costs for culvert clean- ing and main tenance are down, and fish and wildlife habitats and passages have improved as well. Incorporate Resilience into Operations and Maintenance In any agency, O&M staff can be some of the most knowledgeable employees regarding the facilities you oversee. They possess hands-on critical institutional knowledge that can inform proper decision-making on virtually any topic, even those beyond their traditional roles. • Consider preventive and predictive maintenance practices that prepare for potential natural and man-made emergencies as key to keeping operational costs in check and avoiding unforeseen events. The FHWA Climate Change Adaptation Guide for Transportation Systems Management, Operations, and Maintenance (see Appendix D) highlights adjustments to O&M programs ranging from minor to major changes that can help minimize current and future risks. • Enable best practices in O&M of current assets to gain obvious benefits for your agency. • Incorporate O&M input into the design of new assets—this overlooked benefit could dramati- cally improve the lifetime and performance of these assets. O&M staff can use their collective institutional knowledge to steer the design and engineering of assets toward a more resilient approach. Prioritizing feedback from these staff members can highlight easy-to-miss problems that should be addressed in the design of assets. • Establish regular coordination between on-the-ground staff and other departments to discuss hot spot areas and inform investment decisions on the basis of past performance. ✔ Incorporate flexibility in agency policies • The Alaska Department of Transportation and Public Facilities issued a policy direc- tive on winter maintenance coordination that requires all regions in the agency to assist in the event of an emergency, regardless of location. The Wisconsin DOT effectively dissolves district lines within the organization when responding to major events so that resources can be applied where they are most needed across the state. ✔ Purchase versatile equipment • The Alabama DOT purchased versatile equipment to double as snow plows. It has also established mobile stockpiles of traffic control equipment, factoring in likely future needs. Our state residents would rather maintain than build. We track conditions carefully and replace when we start doing too much maintenance. Lowest cost of ownership drives action.

18 Resilience Primer for Transportation Executives ✔ Use maintenance data to identify vulnerable areas • The Oregon DOT uses maintenance dispatch data and weather-related data to map areas within its system most vulnerable to climate impacts. Maintenance personnel are able to identify locations susceptible to weather or other conditions that need to be monitored more closely over time. ✔ Configure tracking systems to create metrics • Configuring work order/labor-tracking systems to better track the impacts of events over time by creating work order numbers, charge codes, or similar codes tied to specific events or types of events has allowed many DOTs to create a metric or severity index that compare expenditures with the relative severity of the event, which helps identify efficiencies and inform budgets. See Emergency Management and Response in Resilience Context Response and recovery are critical aspects of resilience, because it is not possible to mitigate all risks or prevent all events from happening. Quickly responding to an incident or event and getting operations back to normal as rapidly as possible after an event minimizes disruptions and reduces impacts on the transportation system and the community. Your agency undoubtedly has responded to weather-related events, a serious highway accident, or a breakdown of critical infrastructure. The nation as a whole has had to respond to the COVID-19 pandemic by providing essential services while implementing social distancing, appropriate protections for employees, and regular decontamination of public surfaces. Learning emergency response under fire is an all-too-common experience for CEOs of state DOTs. Some types of events are long in developing and may slowly creep up. The consequences of such events may take time—sometimes years—to become obvious. Others, despite the best efforts of engineering and maintenance, always have potential to occur, such as accidents and structural failure. • Know what is out there and be prepared for when events occur. Understand what types of events are likely to occur in your state and the potential impacts those events can have on your agency. By anticipating events and the potential impacts, you can plan in advance. • Recognize that worker safety and providing a healthy and safe workplace, especially in a pandemic, is critical to maintaining ample human resources. • Examine the efficiencies that make your agency nimble during an emergency and explore what can be done to integrate at least some of them into daily operations. • Recognize how the great work your staff does in emergencies can help build the argument with your public and policy makers for resilience planning and funding. Your understanding and leadership of the political implications of the event can shape guidance for the elected official (typically the governor) to whom you report. Highlight the successes of your staff during these times, in order to advocate for greater resources needed to mitigate against and prepare your agency for any future emergency that might occur. ✔ Participate in multiagency resilience groups • Washington State has a multiagency resilience cabinet with DOT participation that holds regular meetings and tabletops across the state.

How to Incorporate Resilience in Your Agency 19   ✔ Establish coordinated processes and procedures • The Colorado DOT established a flood recovery office to coordinate and oversee recovery and resilience efforts after the 2013 floods. ✔ Incorporate risk into recovery • The Colorado DOT adopted a process for its flood emergency relief program on the basis of risk assessment, to justify resilience and mitigation projects at locations that suffered severe damage from the floods. ✔ Use continuous learning and improvement processes • After Hurricanes Lee and Irene in 2011 and Sandy in 2012, the New York State DOT refined its emergency responses and incorporated lessons learned into many practices, from maintenance management to programming, project selection, and managing assets. The maintenance management system allowed the agency to record damages, issue work orders, and capture costs for later federal emergency reimbursement. See Technology and Materials Through a Resilience Lens Technology can play a critical role in resilience by providing valuable information and increasing capabilities critical to resilience. Improving system infrastructure with the tech- nology your agency has in place or could obtain will require mainstreaming the possibilities into planning and programming with appropriate funding. • Existing technologies, such as FHWA’s Road Weather Information System (RWIS) and commercially available decision support systems, can be leveraged to track trends or examine potential scenarios for operational planning. • Rapidly developing technologies provide digitized data acquisition and structural diagnostics through remote, in situ, or portable monitoring/damage detection sensors and devices. • Emergency apps can be loaded onto phones before disasters to provide tools for your personnel. Both the Red Cross and FEMA offer lists of downloadable emergency apps. • GIS allows the tracking, mapping, analysis, and modeling of geospatial data that can assist and inform in asset management and emergency management. Your team most likely already includes GIS analysts, who may benefit from additional training for resilience. • Intelligent transportation systems (ITS) can help enhance resilience. ITS can be used to develop a system for forecasting the effects of weather on transportation systems, traveler information systems, and support for emergency operations. Working together, your traffic management center and your emergency response team can leverage ITS for resilience in rerouting traffic in preparation for or during events. As a term, “technology” often conjures electronic and cyber capabilities, but advances in materials technology are an important part of resilience, too. New and more durable materials, such as high-performance concrete, high-performance steel, smart materials for bridges, reflective paint for roads, and paving materials that better address current and future conditions, are becoming available. ✔ Explore innovative techniques and materials • The Virginia DOT uses innovation to build to last longer, for example, in building corrosion-free bridges with new materials. To get buy-in for higher costs up front,

20 Resilience Primer for Transportation Executives the agency shows benefits, such as savings/cost avoidance down the line, consistent with its goals. ✔ Use materials that better address current and future conditions • In the City of Los Angeles, streets covered with reflective paint were 10 to 15 degrees cooler on average than streets not covered. ✔ Identify means to gather better data at lower cost • The Utah DOT and other states have incorporated drone technology into many different functional areas to provide better information at lower cost within a framework of training and policies to avoid abuse. Applications include topographic surveys, bridge inspections—structures and delaminations—and landslide assessment. Capitalize on the Resilience Theme in Agency Communications Fundamentally, all communication between DOT CEOs and everyone else in their DOT’s universe is about resilience. Every message about a DOT’s achievements, difficulties, necessities, or plans—even reports on ordinary activities—can have the baseline message of resilience in it. That baseline is, “We are working hard to be sure your transportation opportunities won’t be interrupted and, if they are, it won’t be for long.” From that baseline, a CEO can build simple, effective communication strategies and messages for internal and external audiences as a means of building agency resilience. Audiences Resilience is important to every DOT internal and external audience, in different ways. Individuals among the public, businesses, civic and political stakeholders, as well as everyone who works for or with the DOT will have specific “how does this affect me/us?” questions that have to be answered at different times. All audiences want a CEO to be informative and, ideally, to be reassuring about safety, emergency readiness, and the quality and continuity of service. As you are well aware, addressing the issue of funding and reserves is basic to building resilient infrastructure, redundancy, and system security into agency assets. Honest and continued dialogue with the business community and the general public about funding challenges and prioritizations and their impact on service can provide the support you need in your discussions with the governor and the legislature. Key Messages Resilience is not so much the subject of messages on its own, but rather the essential message thread that can hold the fabric of an organization together, no matter what comes. Therefore, the messages critical to your audiences are ones that reflect their needs and your DOT’s capa- bilities to meet those needs. The messages may take a wide variety of forms, but their content has three basics: • What our transportation system provides, how it functions, and what we do to maintain and improve it. People need reasonable expectations about transportation in general and about resilience in particular. They need to know what they can count on and what to hope for when disruption occurs.

How to Incorporate Resilience in Your Agency 21   • How we are working to reduce disruptions and improve safety. No doubt your agency has communications about emergency readiness, response, and recovery built into overall communications and public outreach. To increase public awareness, add the fourth r to your messages—resilience. Share the work your agency is doing to reduce future disruptions by addressing your vulnerabilities and improving your approaches to minimize the consequences of future events. • Our commitment to resilience. Once your agency has defined resilience in terms that make sense for your community, craft a message that makes clear your conviction that your DOT will be an increasingly resilient organization—one that will strengthen community resilience in the process. These three content areas ground almost any message, from the tight and tidy elevator speech to a full keynote address. With remarks and examples for each, you will be ready to tell the resilience story as a meaningful part of any discussion about your agency’s direction, impact, and legacy. Address Cybersecurity Early and Often Cyber incidents migrate from one industry to another as compromises become easier and the rewards of cybercrime become greater. The likelihood of a significant event in any industry is increasing, along with the cost of cyber incidents. Hacking is not the only cause of cyber incidents. Equipment failures, or even maintenance procedures, can cause unexpected cyber incidents. Structural network failures and human error have the potential to occur more frequently than intentional cyberattacks. The impacts of a cyber failure differ widely in duration and cost. For most agencies, the consequences can be significant. Along with economic and potential safety impacts, damage is done to an agency’s reputation and credibility, and the resulting political repercussions can be severe. A rich body of cybersecurity guidance and resources has developed over recent years. Resources for transportation are available from TRB, AASHTO, and other transportation Cyber Resilience Cyber resilience is the ability to identify, prevent, detect, and respond to cyber incidents and recover while minimizing service impact, customer harm, reputational damage, and financial loss. Strategies that support resilience include the following: • Plan for incidents and have approaches to isolate attacks, contain the damage done to systems, and be able to recover gracefully and as quickly as possible. • Establish an enterprise-wide strategic approach to cybersecurity to yield the most long-term benefits. • Expand your organizational risk decision-making and mission priorities to include cybersecurity, if it is not already included. • Advocate for cybersecure policies in your agency procurement processes because vendors often play a major role in the implementation and maintenance of your digital systems.

22 Resilience Primer for Transportation Executives organizations. Establishing and sustaining cybersecurity requires a CEO’s active—and visible— support. Best practices include the following: • Maintaining situational awareness of digital threats. Awareness of digital threats—both intentional and unintentional—is important to becoming a resilient agency. • Fostering a cybersecurity culture. An environment in which cybersecurity best practices are a way of life goes a long way toward preventing and mitigating cyber incidents. Awareness and training, along with established security policies and procedures, are important aspects of building a cybersecurity culture. • Recognizing that users are crucial to cybersecurity in preparing, exercising, and implement- ing backup and downtime processes and systems. Complete protection against cyber incidents is not achievable, and incidents will happen. Assume that a cybersecurity incident will happen in your agency and focus on what will be needed to maintain operations while mitigating the consequences. This is cyber resilience. In an ever-changing security landscape, cybersecurity must be a continuous process, with evaluation and monitoring as key components to identify and manage necessary changes to systems and environments. Having technology in place to provide cybersecurity is only one part of an effective approach.

Next: Chapter 4 - Conclusion »
Resilience Primer for Transportation Executives Get This Book
×
 Resilience Primer for Transportation Executives
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

CEOs of departments of transportation (DOTs) face many challenges, including some that will have serious impacts on people's mobility and safety, and possibly on the tenure of CEOs. Many of these challenges revolve around the resilience of the transportation system—how well it can withstand disruptions from natural causes, catastrophic failures of the infrastructure or cyber events, and how quickly the agency can restore services when they are impacted.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 976: Resilience Primer for Transportation Executives provides a quick grounding in resilience benefits, the CEO’s role in resilience, and approaches taken in various states to increase the resilience of their transportation system. It also offers concepts and tools to lead agencies toward greater resilience.

An electronic brochure, Resilience in Your Pocket, details for practitioners internal and external resilience talking points and action steps.

READ FREE ONLINE

  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. ×

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

    « Back Next »
  6. ×

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

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    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!