Step 3: Set Up for Scenario Planning: Evaluation Tools, Data and Building Blocks
Step 3 of the scenario planning process begins by selecting tools that will be used in subsequent steps to assemble and evaluate a range of scenarios in order to compare the estimated outcomes. Two types of evaluation tools are recommended: Metropolitan GreenSTEP, a transportation GHG model developed by ODOT, and a land use sketch planning tool. Using these tools requires deciding a geographic scale for analysis, compiling data and other information needed to create scenarios, and setting up the tools for scenario building. Some new planning concepts and analysis processes are presented here.
Step 3 provides an overview of the tools recommended for the scenario planning process and their interrelationships. This chapter also describes setting up the tools and the types of data needed. Setting up the tools and gathering the data in this step will set the stage for developing and evaluating scenarios in Steps 4 and 5. (For a complete explanation of the full suite of GHG assessment modeling and analytical tools in Oregon, please refer to the Modeling and Analysis Tools Report, a component of the Oregon GHG Reduction Toolkit).
Recommended scenario planning tools include the state’s transportation GHG model, Metropolitan GreenSTEP, and sketch planning tool(s)
that allow for creation and comparison of land use and transportation scenarios. 1) Metropolitan GreenSTEP allows planners and decision makers to analyze the effects of a large number of factors on transportation GHG emissions (e.g., land use, transportation system, pricing, technology). Metropolitan GreenSTEP has the ability to quickly test hundreds of high-level policy scenarios. It can also be coupled with a sketch planning tool to estimate transportation GHG emissions from more detailed land use scenarios. 2) Sketch planning tools involve creating land use types, called building blocks, which are then used to construct different detailed land use scenarios in order to evaluate alternative future land use patterns.
Use of the recommended scenario planning tools will be described in three major steps as follows:
- Metropolitan GreenSTEP is used to model a number of high-level policy scenarios for impacts on transportation GHG emissions and other related evaluation measures, as defined by local community values. This is an opportunity to assess the range of possibilities and to use the results in building a coalition to spearhead the scenario planning process.
- A sketch planning tool is then used to develop scenarios at a more detailed scale. In this step, the process moves from geographically generalized analysis to refining data at a specific geographic scale.
- After developing geographically detailed scenarios using sketch planning tools, Metropolitan GreenSTEP is again used to evaluate transportation GHG emissions and other evaluation measures.
As with most analytical tools, an initial setup is required prior to using the tools. A base year
will need to be established as the starting point for scenario planning along with a planning year
representing an end date for the future scenarios. The sketch planning tool will require designation of a planning unit
size, reflecting the geographic scale at which the scenarios will be designed. A part of the setup for both tools will be collecting data
about existing conditions and plans in place, along with future forecasts.
Set a Base Year and Future Planning Year
Selecting a base year is an essential first step to define the process and to gather the data needed for the tools. A base year scenario will approximate existing conditions in the metropolitan area using data from that time period, which officials and public stakeholders can verify and confirm. The base year provides a benchmark for comparison of existing conditions with the reference case and future alternative scenarios.
2005 is the recommended base year for conducting scenario planning to meet metropolitan GHG reduction targets because the state and most local jurisdictions have comprehensive and available data for that year. If there are significant studies, inventories or other published data (such as the 2010 Census) that would enable more accurate or in-depth analysis, a more recent base year may be chosen. However, since the adopted targets for metropolitan GHG reduction are based on decreases from 2005 emission levels, some additional work would be needed to properly account for changes in emissions from that 2005 base year.
The minimum future planning year for the reference case and alternative scenarios should be 2035. Because most local land use and transportation plans currently extend to this date, or close to it, making needed information readily available, the adopted metropolitan area GHG reduction targets are set for 2035. However, scenario planning is also an opportunity to engage in a long-range visioning process that looks beyond normal planning processes and timelines. Using a longer planning period enables a community to see the cumulative impacts of current trends more clearly. It also allows the community to consider a broader range of options, which may take more time to implement, given that major changes in land use and transportation patterns take a long time.
The longer timeframe embodied in the STS looks out to 2050 and should be taken into consideration in the development and evaluation of alternative scenarios. The STS also includes county level data and estimates about population, age, income, and fuel prices to 2050. The data and assumptions used to create the 2035 GHG reduction targets for light vehicle travel were themselves based on 2050 projections produced by Metropolitan GreenSTEP. Metropolitan GreenSTEP is capable of producing estimates and projections for both 2035 and 2050.
If scenario planning is based on a future planning year other than 2035, the development, analysis and evaluation of expected outcomes for the reference case and alternative scenarios should also include an estimate of outcomes in 2035 to address the adopted GHG reduction targets.
The Guidelines recommend and focus on two analytical scenario planning tools. First, the Metropolitan GreenSTEP model used to estimate the effects of a large number of policies including, but not limited to, land use and transportation on transportation GHG emissions and other evaluation measures. Second, a GIS based sketch planning tool used for efficient creation and evaluation of alternative future land use patterns, which can provide data for Metropolitan GreenSTEP to evaluate transportation GHG emissions. (Other tools are also available for evaluating GHG emissions. For guidance on the range of modeling and analytical tools in Oregon to assess transportation GHG emissions, please refer to the Modeling and Analysis Tools Report in the Oregon GHG Reduction Toolkit.)
Applying the Evaluation Tools: Using Sketch Planning Tools and Metropolitan GreenSTEP Together
Metropolitan GreenSTEP and sketch planning tools each have many strengths and can greatly inform the planning process as stand-alone tools. However, using these tools together to fully benefit from the unique strengths each provides allows for the most comprehensive analysis for scenario planning. The recommended process and use of these tools for scenario planning involves three analysis phases.
First, Metropolitan GreenSTEP is used to conduct an initial, high-level test of a range of policy scenarios for impacts on transportation GHG emissions and other transportation related evaluation measures. This large set of scenarios allows stakeholders to select and focus on the types and combinations of policies that meet their desired outcomes and overall community goals. This is an opportunity to gauge the range of possibilities and to use the results in building a coalition to spearhead the scenario planning process. Land use inputs at this stage are generalized and large scale (i.e. regional transportation service levels not specific projects).
Then sketch planning tools are used to further detail future land uses and scenario concepts for additional analysis by GreenSTEP. In this step, the process moves from the general to the specific, using the geographic scale selected earlier, possibly as specific as parcels. The sketch planning tools described in the Guidelines build on the functionality of GIS to allow testing of different land use and transportation options for the future. Land use inputs using the building blocks defined earlier are much more detailed.
At this point, the outputs from the sketch planning tool can be used to define new Metropolitan GreenSTEP inputs for a select number of alternative scenarios. After developing geographically specific scenarios using sketch planning tools, the data is converted to translate the outputs from the sketch tool to be usable in Metropolitan GreenSTEP. This allows for a more complete evaluation of how proposed land use scenarios will perform given the policies that the state has assumed and the metropolitan area has chosen to test. This allows refinement of the measurements from the initial analysis in the first phase and more detailed analysis of transportation GHG emissions and other transportation related evaluation measures. Using Metropolitan GreenSTEP and sketch planning tools together provides the flexibility to evaluate how proposed land use scenarios will perform in relation to the policies the state has assumed, as well as the outcomes and aspirations defined by a local community.
By feeding the more detailed land use scenario back into Metropolitan GreenSTEP to do the GHG assessment, the land use concepts, non-land use concepts, and policies an area is planning on pursuing will be accounted for and allowed to impact one another in the analysis. Sketch planning tools do not take into account federal or statewide policies, such as the efficiency levels of the future fleet or taxing policy impacts on VMT. For these reasons it is necessary to use Metropolitan GreenSTEP to produce the final GHG evaluation out of the sketch planning process. Sketch planning tools can provide GHG estimates to help refine land use scenarios (development visions) as they are being created by planners or the community in Step 5. A final evaluation should occur with the land use information from those scenarios input back into Metropolitan GreenSTEP to get a more accurate measure of GHG.
Metropolitan GreenSTEP Model
ODOT developed the GreenSTEP model to evaluate a range of different policies and factors affecting GHG emissions from the transportation sector to help guide statewide policy decisions. GreenSTEP was the primary analysis tool employed in the development of the GHG reduction targets and the STS. Metropolitan GreenSTEP is an adaptation of GreenSTEP intended for use at the metropolitan level for scenario planning.
Both versions of GreenSTEP estimate emissions based on individual household characteristics such as income, household size, urban density, land use mix, and transit service. These characteristics then respond to assumptions about future technology and transportation and land use policies. In addition, factors such as electric car adoption programs, travel demand management programs and parking policies can be tested.
Metropolitan GreenSTEP allows for the measurement of transportation sector GHG emissions, other indicators of community values, and enables the comparison of many policy scenarios. Metropolitan GreenSTEP has enabled the state and the Portland area’s Metro to evaluate many different policies for reducing transportation sector GHG emissions.
When Metropolitan GreenSTEP is used initially by itself, a range of geographically generalized land use and transportation policies that a local area might want to pursue can be tested, such as:
- Urban characteristics: density, mixed use, public transportation, non-motorized transportation, parking management.
- Road characteristics: the supply of freeways and other arterials and the management of operations.
- Marketing characteristics: such as the deployment of employer-side and household-side travel demand management programs, eco-driving, low-rolling resistance tires, and pay-as-you-drive insurance.
In addition, Metropolitan GreenSTEP can be used to evaluate the implications of changes in the vehicle fleet, vehicle and fuel technologies, and various types of pricing. However, these are typically viewed as factors that require state and/or federal action and are not actions that a local area would generally pursue.
Metropolitan GreenSTEP can be used as a strategic level tool to evaluate many scenarios relatively quickly. This approach is the first phase of the three phase approach described earlier in Applying the Evaluation Tools.
Many interrelated factors influence GHG emissions, and adjusting one can directly impact others. For example, vehicle ownership relates to how the vehicles are used. The way the transportation network is managed and priced effects future land use development. Land use development affects how vehicles are used. Vehicle use, especially the distance vehicles are driven, impacts the market penetration for electric vehicles. These are just a few examples of how different factors impact and influence one another. (Figure 5 provides an illustration of these relationships.)
Because of these complicated interactions, Metropolitan GreenSTEP is constructed to analyze the interactions at a very disaggregate level, modeling decisions at the household and vehicle level. So while the inputs only need to be high-level regional approximations, based on state and national data on travel behavior, the computations occurring within Metropolitan GreenSTEP estimate how individual households will make decisions based on different conditions. For example, Metro’s initial runs using Metropolitan GreenSTEP divided the entire Portland metropolitan area into 20 different districts to distinguish different land use types based on the 2040 Growth Concept, which focused on town and regional centers. GreenSTEP then was able to model anticipated household travel behavior based on those districts.
However, as detailed later in this step, sketch planning tools can be used to help communities compare and agree on varying development strategies at a very detailed level, even specific parcels if desired. The detailed land use visioning done with sketch planning tools is ideally developed in conjunction with Metropolitan GreenSTEP, which then allows Metropolitan GreenSTEP to provide GHG reduction estimates for specific land use patterns developed with the sketch planning tool, while accounting for the interactions and potential synergies of all the other (non-land use) policies.
Baseline Planning Assumptions
Metropolitan GreenSTEP uses a large number of inputs to model GHG emissions. However, some of the inputs will be used from the data developed for the analysis of metropolitan GHG target rules and for the STS. The default assumptions in GreenSTEP address:
- Fuel Prices
- Statewide policies on pricing and finance (e.g. gas tax, VMT tax, carbon fee, tolling)
- Pay-as-you-drive insurance
- Vehicle Fleet Mix and Age
- Fuel economy goals
- Advanced vehicles in the fleet (e.g. electric vehicles)
- GHG production from Oregon’s electricity generation
- Future fuels and fuel standards (e.g. low carbon fuel standard, amount of GHG produced per unit of fuel)
Selecting the Geographic Scale for Metropolitan GreenSTEP
A level of detail needs to be selected for use in the metropolitan area and incorporated into Metropolitan GreenSTEP. The statewide GreenSTEP model uses counties as the minimum geographic units. For metropolitan area scenario planning a smaller unit of geography should be employed to make the model more sensitive to localized details. Census tract block groups are the recommended starting point. Much of the data required for the tool is available at this geographic level, or within smaller geographic areas such as Traffic Analysis Zones, which often nest within the tracts.
The goal in determining the geographic scale is to find areas small enough to reflect significant differences between sub-areas within the metropolitan area. For example, residents in downtown, be it Bend or Medford, are likely to have different travel patterns, and other characteristics, than people in neighborhoods dominated by single-family homes, such as South Eugene or West Salem. At the same time, there is no significant benefit of smaller sub- geographies if there are few differences between the residents’ travel behavior and lifestyles throughout the area.
Collecting Data for Metropolitan GreenSTEP
To model prospective land use and transportation policies at a local or district level, a number of inputs are required for each policy area. Figure 10 provides a list of inputs that will be calibrated and selected for the local jurisdictions. The Community Design, Pricing, Marketing and Incentives, and Roads inputs will be locally generated and therefore do not have standard values for all metropolitan areas. The Fleet and Technology inputs use values from the Target Rule as a starting point for all metropolitan areas. Input values can be found in the Target Rule
Policy Area Inputs to choose from for use in Base Case, Reference Case and alternative scenarios.
|Urban growth boundary (UGB) (rate of expansion relative to rate of population growth)|
|Households in mixed-use areas by census tract or county (percent)|
|Rate of growth of public transportation service (revenue mile growth per capita compared to base year level)|
|Bicycle or light vehicle mode share|
|Work and non-work parking extent and cost|
|Pay-as-you drive insurance (percent households and cost)|
|Gas tax (includes state and federal gas tax, reference scenario assumes HB 2001 gas tax increase)|
|Carbon emissions fee|
|Vehicle travel fee|
|Marketing and Incentives|
|Households participating in individualized eco-driving marketing programs (percent)|
|Participation rate in individualized marketing and employer-based commute programs (percent)|
|Extent and participation in car-sharing|
|Rate of growth of freeway and arterial lane miles|
|Fleet turnover rate/ages|
|Auto fuel economy - internal combustion engine|
|Light truck fuel economy - internal combustion engine|
|Auto fuel economy - plug-in hybrids|
|Light truck fuel economy - plug-in hybrids|
|Carbon intensity of fuels (CO2e grams/megajoule)|
|Percent of autos that are plug-in hybrids or electric vehicles|
|Percent of light trucks that are plug-in hybrids or electric vehicles|
Sketch Planning Tools
Today, sketch planning tools facilitate the development and evaluation of a variety of land use and transportation alternative scenarios. The discussion in this guidance document focuses on the sketch planning tools that are software extensions to GIS and allow planners to “paint” building blocks (descriptive land use types described in detail below) and “draw” transportation improvements on the landscape to create unique land use and transportation scenarios.
The GIS based sketch planning tools are used to report various land use, housing and environmental measures based on designated building blocks. This process allows convenient comparisons of the impacts of different land use and transportation arrangements. Sketch planning tools currently used in Oregon are Envision Tomorrow and INDEX.
A major benefit of using sketch planning tools is the ability to conveniently develop many possible future land use scenarios with detailed information describing the locations, types and intensities of land uses. This land use information can then be output and used by other evaluation models and tools in the planning process. These other models include traditional traffic analysis zone (TAZ) based travel demand models, transportation post-processing models that estimate vehicle trip reductions (also known as traffic calculation models), energy models, land use models and infrastructure models . Land use models such as Metroscope and LUSDR are also a potential source of information for the scenario planning process and can assist in allocating the growth forecast. However, the use of such land use models is optional and do not need to be directly used in scenario planning.
Collecting Data for Sketch Planning
Development of base year and reference case scenarios – using sketch planning tools - relies on compiling and developing accurate, region-wide land use and transportation data for the base year and the future planning year. Some of this data, such as the transportation network and the geographic scale are displayed on a base map that will serve as a guide when painting scenarios.
Selecting the Geographic Scale for Sketch Planning
Scenario planning analysis can be conducted at a variety of geographic scales. The sketch planning tool relies heavily on geographic data in order to allow for testing different geographic combinations of land uses. The size of the metropolitan area and the resources available often dictate how coarse or fine the geographic planning units should be. For instance, a regional scenario project for a large MPO like Portland Metro may use either an acre-sized grid cell planning unit or census blocks, while a project for a smaller MPO could make use of aggregated parcel data (if the data resources are available) to create planning units smaller in scale and more finely grained.
Developing Building Blocks for Sketch Planning
Sketch planning tools use building blocks that describe the different types of land uses that exist within the metropolitan area or are planned for the future. Each building block is comprised of a mix of different types of buildings along with assumptions about characteristics such as the amount of land devoted to streets, parks, and civic areas. The building blocks represent the places people are familiar with, such as main streets, town centers, and residential neighborhoods. Communities that have engaged in scenario planning have typically used between 10-25 different building blocks depending on the size of the area, and diversity of places within the area. Comprehensive plan land use categories will inform the building blocks. When assembling the building blocks within the sketch planning tool (often into a spreadsheet), refer to the comprehensive plans of local jurisdictions for ideas on the types of places that should be represented in the scenarios. The purpose is not to create a category to match every city’s comprehensive plan category, but rather a description of all of the places that exist today, and those that may exist in the future.
Once the building blocks are constructed, they are painted onto the base map of the metropolitan area using the sketch planning tool. Each building block carries with it values that describe the characteristics of the places they represent.
Through use of the sketch planning tool, building blocks are used to estimate likely outcomes, and comprise the foundation of the future land use scenarios. Baseline data and information about each building block used in the sketch planning tool allows the sketch planning tool to calculate results for many of the evaluation criteria discussed in Step 2. Examples of the outcomes that sketch planning tools estimate include: employment and housing densities, new impervious surface (e.g., rooftops and parking lots), the amount of land developed and redeveloped, total number of parking spaces, mix of housing types, mix of employment types, and if calibrated to local markets, the relative value of new development, along with other measures. Each sketch planning tool handles building blocks a little differently, but their fundamental variables are related to housing and employment densities and urban design. (See the Technical Appendix
for more detailed discussion and examples.)
After applying these building blocks across the planning area, for the base conditions and the reference case scenario, household information is extracted from the building blocks, through a conversion process (described later in Step 3, Preparing the Sketch Planning Results for Analysis with Metropolitan GreenSTEP) to enable Metropolitan GreenSTEP to calculate the remaining evaluation criteria. The scenario also produces data that can be transferred to TAZs or census tracts, which is what Metropolitan GreenSTEP will likely use, including population, housing units and employment. This data can then be fed into the regional transportation model to determine how the potential land use pattern impacts travel behavior.
Within a spreadsheet, each building block will be assigned a mix of building types, each having an associated job and housing density. Examples of building types include: mixed use residential four-stories, garden apartment, compact single family home, office, main street retail, and business flex. Because building blocks make it possible to measure evaluation criteria that rely on information tied directly to individual buildings and uses, many of the assumptions are built into the individual building spreadsheets (called prototype buildings), which are then linked to the building block spreadsheet and grouped together to form building blocks. (Be sure to show the key characteristics of building blocks needed to generate estimates of key outcomes, especially land use and transportation related outcomes, e.g., street network, density, parking.)
Building blocks are primarily used in the sketch planning tools to perform the land use analysis. While building blocks themselves do not include measurable transportation characteristics, they are intended to match or complement specific transportation investments included in the scenario. The transportation design and assumptions serve as a guide so that placement of building blocks is consistent with, and takes advantage of, planned transportation improvements and programs. For example, it may not be highly effective to locate auto-oriented, low-density building blocks in an area of the region where transit investment is already in place or planned. Conversely, it could be effective to place high-density and mixed-use building blocks in areas along transit lines and in areas with well-connected streets. The sketch planning tool itself will not incorporate the transportation infrastructure in delivering its evaluation criteria. The sketch planning tools which produce transportation estimations are based on just a few land use factors such as density, use mix, the connectedness of the street network, and availability of transit service.
The base and reference case scenarios should be based on the financially constrained transportation network. However, testing additional investment strategies (transit, sidewalks, bike paths, additional infrastructure, etc.) either generally through Metropolitan GreenSTEP, or in detail through a travel demand model, can be a productive way to evaluate and prioritize other, non-funded investments.
Recommended Building Blocks
Oregon’s metropolitan areas have similar land use patterns. Each region includes a primary downtown area, a number of smaller town or neighborhood centers, and larger single-use areas like residential neighborhoods, commercial strips, industrial areas and parks. Similarly, each of Oregon’s metropolitan areas is planning for some newer development types, like transit-oriented developments and mixed-use neighborhoods. The recommended building blocks are suggestions that represent both existing forms of development common in the metropolitan areas of Oregon and new types considered possible over the next 10-20 years. Much more detail about the recommended building blocks (i.e. building types, FAR, number of stories, parking factors, street network, level of transit service or other key characteristics used by sketch planning tools to generate estimates of outcomes) is provided in the Technical Appendix
|City Center (similar to downtowns in Eugene, Corvallis, Bend, Salem, and Medford)
||25 - 40
||60 - 100|
|Town Center (similar to downtowns in Ashland and Coburg)
||20 - 30
||30 - 50|
|Mixed-Use Neighborhood Center
||15 - 25
||0 - 15|
||15 - 25
||0 - 2|
||15 - 25
||20 - 30|
||30 - 50
||8 - 10|
||8 - 9
|Single-Family Residential Area
||4 - 7
|Multi-Family Residential Area
||12 - 24
||15 - 35|
||25 - 40|
||8 - 10|
Preparing the Sketch Planning Results for Analysis with Metropolitan GreenSTEP
Transferring data from a sketch planning tool to Metropolitan GreenSTEP may require some additional post processor formatting and analysis depending on the type of sketch planning tool and the number of Metropolitan GreenSTEP policy areas incorporated into the sketch planning tool interface. Data produced by the sketch planning tool will need to be manually analyzed and aggregated before entering the data into Metropolitan GreenSTEP. Sketch planning tools assign dwelling units to land uses, whereas Metropolitan GreenSTEP is household based. Therefore, the results measured in dwelling units produced by the sketch planning tool need to be translated into households for use in Metropolitan GreenSTEP. For instance, if there are 100 dwelling units in a particular census tract used in the sketch planning tool, that data is stored as one record of data. For Metropolitan GreenSTEP, 100 records need to be created from that one record – one for each of the households. The process for analyzing and aggregating the data for transfer between sketch tools and Metropolitan GreenSTEP should include at a minimum a density of households and whether or not it is in a mixed-use environment. Each of the household records may have additional characteristics attached to them, such as income, access to transit, and access to personal vehicles. The geographic scale of Metropolitan GreenSTEP delineated previously in this step must be kept consistent when preparing the sketch planning results in order to easily aggregate to the appropriate geography (e.g., census tract, district, county).
This step of the scenario planning process involved selecting the tools and assembling the data to be used in succeeding steps to develop and evaluate alternative scenarios. Deciding which combination of tools to use depends on the data and resources available, and how scenario planning fits with other local and regional planning work. The Metropolitan GreenSTEP model (developed by ODOT), which provides metropolitan areas with a powerful tool to evaluate GHG and other transportation related outcomes of a broad range of regional policy choices, is recommended. Sketch planning tools enable local planners to construct and evaluate detailed land use and transportation options, based on compilation of detailed information about local conditions and construction of data based land use building blocks. With these tools in place, local planners can move forward in Step 4 to using the tools to document existing conditions and estimate the likely result of currently adopted plans in relation to community goals and values, as well as GHG reduction targets and goals.
Case Study: Metro and Metropolitan GreenSTEP
Metro utilized a version of Metropolitan GreenSTEP with 20 sub-regional geographies. Metro delineated these minimum geographic units based from its 18 district TAZ map and then adjusted them to Census boundaries to be consistent with Metropolitan GreenSTEP data inputs. Each metropolitan area will be able to delineate the minimum geographic units, or sub-regional geographies that it feels work best for the land use scenario development using sketch planning tools.
Metropolitan GreenSTEP and sketch planning tools are described in greater detailed in the Technical Appendix
and the Modeling and Analysis Tools Report in the Oregon GHG Reduction Toolkit.