FHWA Scenario Planning Guidebook
Phase 4. What Could the Future Look Like?
Create baseline and alternative scenarios.
Phase 4 focuses on developing multiple scenarios, including baseline and alternative scenarios, to assess how future changes could impact the transportation system as well as travel demands or needs. Scenarios combine the trends and variables identified in Phase 2 and values, goals, and aspirations identified in Phase 3 with appropriate policy and investment responses, creating plausible and distinct alternative pictures of how the community, region, or study area might look and function in the future. These alternatives translate broad concepts and possibilities into compelling narratives or stories that can help planners, politicians, the public, and others to weigh and consider transportation choices and priorities. The scenarios provide a common framework for all parties to discuss the costs and benefits of transportation decisions while taking future uncertainties into consideration. Many agencies have involved the public in all stages of Phase 4.
To develop scenarios and later assess their impacts, some agencies have used travel demand models or models developed specifically for transportation and land-use scenario planning. Examples of scenario planning analysis tools include INDEX, CommunityViz, MetroQuest, and UrbanSim. Many of these tools use a GIS format so that users can geospatially plot scenarios and more easily visualize outcomes. Use of these analysis tools to assess scenarios is discussed in further detail in Phase 5. Agencies can facilitate the scenario planning process by identifying appropriate tools or models as early as possible.
The types of scenarios developed and the specific elements they include will vary depending on the focus and goals of the scenario planning process. A few examples of different types of transportation and land-use scenarios and associated questions are provided below:
- Baseline scenarios: What might the future look like given the continuation of current policies, programs, and development forms?
- Growth/socioeconomic scenarios: What might the future look like given different population or growth projections?
- Policy scenarios: What might the future look like given combinations of different policies, actions, or strategies, such as policies focused on mode splits, asset management, or preservation?
- Environmental scenarios: What might the future look like given different environmental trends and needs?
- Economic scenarios: What might the future look like given different trends in various sectors of the economy?
- Hybrid scenarios: Combinations of several scenario types.
There are several steps to Phase 4. Agencies should:
Each step is listed below, along with associated key questions that agencies can consider. Some steps provide examples of additional issues or questions for further consideration.
Step 4.1: Identify needs for scenario development.
- Determine what general type(s) of scenario(s) is/are necessary for the effort, such as:
Scenarios do not need to address every future possibility; rather, they should help to foster discussion around key issues facing the study area.
- Consider how scenarios should be labeled or named. Some general examples of scenario names include traditional growth, compact center, moving inward, system preservation, and technological innovation. Scenario names can be associated with values; to avoid potential bias, practitioners should consider using more neutral labels, such as regional scenario, Scenario A, or Scenario 1.
- Identify the resources that will be necessary to develop scenarios. This step must consider the extent and format of available data (compiled in Phase 2) and its compatibility with various analysis tools. Address the following questions:
- Will scenario analysis use quantitative or qualitative data, or both?
- Will building or analyzing scenarios require significant data collection or software development efforts?
- What data will be required?
- What data and analysis tools are currently available to support these efforts?
- What additional resources could be used if quantitative data are unavailable or not needed in the effort?
- Determine what elements of scenarios need to be measured on the basis of public input and the future values, goals, and aspirations documented as part of Phase 3. Next, identify the tool that can measure these factors most effectively given the specific conditions facing a particular agency. When choosing a scenario analysis tool, the primary factors to consider are applicability, cost, and complexity.
- What questions will the tool help to answer?
- Has the tool been applied in other regions in the state or in regions addressing similar issues?
- Are existing analysis tools sensitive to the key factors and driving forces identified in Step 2?
- How will scenario descriptions be translated into modeling terms?
- How much will this tool cost?
- Are there sufficient staff resources to prepare and run the tool, or are additional resources needed?
- What data does the tool require and at what scale? What amount of data is required?
- What analysis capabilities (outputs) are desired? What outputs will the tool produce and in what format?
- Will outputs be easy for the public or other stakeholders to understand?
Using Qualitative Analysis
MWCOG developed qualitative scenarios as part of the Greater Washington 2050 initiative, an example also described in Phase 3. The qualitative scenarios focused on a wide range of trends. Scenario analysis was conducted through discussions with regional leaders in a workshop format.
MWCOG believed that the use of qualitative scenarios was best suited for the Greater Washington 2050 initiative as they could capture a wide range of variation and potential trends. While quantitative scenario modeling is useful and appropriate for some scenario planning efforts, MWCOG noted that some models rely on forecasts rather than outside-the-box thinking to assess future impacts. In addition, MWCOG noted that some models might portray only modest variations among scenarios and might not be finely attuned to land-use pattern changes.
MWCOG based its qualitative scenarios on themes that emerged from focus group interviews. These themes were related to the region's economy, energy prices, and technology.
Local professionals and researchers reviewed scenario assumptions to ensure their plausibility. During the one-day scenario thinking exercise, participants discussed scenarios. Additionally, local experts in climate change, technology, and economics presented on key regional trends to provide credibility, context, and additional details for the scenarios.
Step 4.2: Refine existing analysis tools or the travel demand model if necessary.
- Identify factors to which the analysis should be sensitive. In Phase 5, these factors might be refined into indicators for measuring scenario impacts or effects.
- Determine whether and how each factor is incorporated into existing travel demand models or analysis tool.
- Refine model(s) or tools to incorporate sensitivity to the key factors. For example, the Southern California Association of Governments is currently working to add an analysis of greenhouse gas emissions to its transportation and land-use model.
- Perform validation and calibration if necessary.
- Consider supplementing models or tools with research and/or qualitative analysis for factors that cannot be directly incorporated.
Step 4.3: Prioritize trends and factors (identified in Phase 2) important to transportation and land use; assess interaction with goals, aspirations, and values (identified in Phase 3).
- How would these trends and factors evolve in the future and what might the impacts be on transportation and land use? For example, assuming a certain percentage of future population growth, where would activity centers be located and what percentage of jobs would be located in these centers? What mode(s) of travel might the population use to access jobs? In the Washington, DC, region, the physical location of Federal government offices has a major impact on transportation needs. MWCOG developed a Federal government dispersal scenario to investigate impacts if this trend did not continue.
- Which changes are predictable and which are difficult to predict?
- What are the key assumptions underlying travel demand forecasts? What would happen if these assumptions changed?
- Are mandated data, such as state-mandated population forecasts, reflected in the forecasts?
- How are other organizations, stakeholders, or agencies in the state, community, region, or study area likely to respond to possible changes? How might these responses affect future land-use and travel demand?
- How do the goals, aspirations, and values articulated by stakeholders in Phase 3 interact or compare with evolving trends and factors?
Step 4.4: Identify potential strategies or actions to address trends.
- Consider the strategies, actions, investments, or potential responses that could support addressing the important trends that will occur over time. For example, assuming that fuel prices increased dramatically, what policies and investments would help to keep the region strong and competitive?
Step 4.5: Compile the trends and strategies identified in Steps 4.2, 4.3, and 4.4 into several scenarios. Each scenario offers a plausible alternative vision of how the future could evolve and how the state, community, region, or study area could respond.
- Develop a baseline scenario that reflects the baseline analysis and assumes no changes in actions, policies, and investments.
- Develop several alternative scenarios by varying the assumptions that underlie travel demand forecasts, growth forecasts, or other anticipated trends. The number of scenarios can vary; two to four is generally sufficient to provide a range of alternatives without overwhelming stakeholders.
- If software tools are used to develop scenarios, input necessary data to build both baseline and alternative scenarios.
Step 4.6: Communicate scenarios to stakeholders.
- Consider using visualization tools or other interactive techniques (see examples below) to help stakeholders understand scenarios.
- Develop a narrative or set of assumptions to describe a developed or modeled scenario.
Using Visualization Tools to Develop and Depict Scenarios
A variety of visualization tools and techniques* can help to communicate the look and feel of different development types and the impacts of scenario choices. Several examples are shown and described below:
- Chips exercises are a technique in which workshop participants place paper or plastic chips on a map to indicate areas of preferred growth or development. The results can be digitized using GIS-based software and presented to participants for validation and review.
- Place-type renderings present a human-scale look and feel for development types. This example was developed as part of CMAP's GO TO 2040 effort. For more information, see www.goto2040.org.
- Schematic images can illustrate a scenario for a broad area. This example shows the Harris Ranch area of Boise, Idaho. For more information, see www.idahosmartgrowth.org/index.php/about.
- Many software programs are available that use GIS or visualizations to demonstrate scenario impacts and effects. This example shows how CommunityViz can depict a scenario. Other software program examples are provided in the overview to Phase 4.
* For more information about visualization tools and techniques, see the conclusion of this guidebook. Additional resources include:
Phase 4 Outputs
Phase 4 has several possible outputs, including identification of an appropriate scenario analysis tool or refinement of the travel demand model if necessary. An additional possible outcome of Phase 4 is the development of several scenarios, including a scenario focused on baseline conditions and alternative scenarios that describe plausible, distinct futures for the state, community, region, or study area. Scenario descriptions should include assumptions about future trends and changes as well as potential responses, actions, and investments. Descriptions should use terms that stakeholders can easily understand.