Resources: Land Use and Transportation Modeling Tools - CorPlan Model, Charlottesville, VA

Table of Contents

PROJECT SNAPSHOT

Traffic congestion was a growing problem in the Charlottesville, VA region in the early 1990s. The most apparent solution was to build a new bypass. The area's citizens were actively involved in local planning efforts, and were unwilling to accept road expansion as the only answer. When other areas tried this approach, they found it to be unsuccessful in reducing congestion. Charlottesville's citizens were concerned about repeating this mistake - if building your way out of congestion has not worked in other areas, they asked, why should it work in ours? In addition, adding a major new road would be a huge, expensive effort, and there would be political ramifications of cutting through mountains and historic areas to build the bypass. It would also contradict regional policies.

The region's planners wanted to incorporate the public's concerns, but they found that there was a shortage of tools to address local planning issues. The state's transportation model, MINUTP, was the only available tool to analyze traffic reduction proposals; data constraints prevented it from offering alternative solutions to the bypass. In light of these limitations, the Thomas Jefferson Planning District Commission (Commission) decided to develop CorPlan, a simple, less data-intensive model that would address small city land use and transportation planning issues. CorPlan is a community-based planning model that is funded by a Federal Highway Administration (FHWA) Transportation and Community and System Preservation (TCSP) grant. The intent is to use CorPlan to achieve a regional strategy that will serve as the foundation for the community's 50-year vision.

The model relies on neighborhood-level distinctions (community elements) to estimate land development potential and how that potential translates into the location of households and jobs. The community elements (CE) include data on land use, infrastructure, and socioeconomic characteristics and the amount of land that is available for development. This information is used to generate development scenarios and the associated transportation options for the region.

The model's strength is in the way it incorporates the public's views and the way it uses neighborhoods to build larger planning scenarios. Community elements, the building blocks of CorPlan, describe neighborhood types in straightforward terms, diagrams, and photographs understandable by the public. In the first set of workshops, planners used the model to illustrate the public's perceived vision of the neighborhoods and asked them to discuss what they liked and did not like.

By not focusing solely on numbers, the citizens could see what the alternatives would actually look like in their community. In a second set of workshops, the participants were asked to take a more "birds-eye" view of their area and how they wanted their neighborhoods to mesh with adjacent areas. These results were used to help develop the alternative regional scenarios.

CorPlan was designed to be a tool for both planning professionals and the general public. Ultimately, the Commission's goal is to use CorPlan to monitor growth patterns and identify how and when to influence regulations that affect local planning efforts.

Top of Page

SUMMARY

CorPlan is a community-based planning model developed for the Charlottesville, Virginia region, specifically the Eastern Area Planning Initiative. It is funded by a Federal Highway Administration (FHWA) Transportation and Community and System Preservation (TCSP) grant. The CorPlan model incorporates regional land use goals, developed through visioning exercises with the public, community leaders, and elected officials, into a regional plan that will serve as the foundation for the community's 50-year vision.

CorPlan - Charlottesville, Virginia

The model relies on prototypical community definitions (community elements) to estimate land development potential and how that potential translates into the location of households and jobs. The community elements (CE) are building blocks for the regional plan. Each CE includes data on land use, infrastructure, and socioeconomic characteristics and the amount of developable land. This information is used to generate development scenarios and the associated transportation options for the region.

CorPlan was designed to be a tool for both planning professionals and the general public. It uses laymen's terms and readily available data sets, software, and hardware. The liberal use of pictures and plan graphics simplifies the message and greatly facilitates the public participation aspect of regional plan development. The long term goals are to use CorPlan to monitor regional growth patterns and identify how they are affected by local planning decisions and to develop local planning regulations that achieve regional smart growth.

Top of Page

INtrODUCTION

Background

CorPlan was developed in response to two concerns: 1) growing traffic congestion and public reluctance toward road expansion; and 2) the inability to use existing tools to implement adopted planning goals and "livability" policies for the region. A growing grass-roots support and active citizen involvement in directing planning efforts for the Charlottesville region also fueled CorPlan's development.

The area has seen tremendous growth in a relatively short amount of time. Currently, the population of the 1,600-square mile study area is approximately 175,000. This represents a 16 percent growth rate between 1990 and 1998, compared to a state growth of 10 percent. County growth rates ranged from nine percent in the suburbs to 50 percent in rural areas, while the city center lost six percent of its population. It is expected that by 2050, the total population will nearly double.

Such rapid population growth brings additional problems, primarily transportation-related. Projected growth in the region's traffic was a major stimulant to action, because despite non-construction efforts to alleviate congestion, the recommended solution for the area was to extend a bypass road entirely around Charlottesville. This was an unpopular solution with planners and citizens because of the sheer size of the effort, the potential expense, the political ramifications of cutting through mountains and historic areas to build the bypass, and the fact that it contradicted regional policies and the public's desire.

The Thomas Jefferson Planning District Commission had traditionally relied on the state's transportation modeling and planning efforts which were highway-oriented and ineffective in addressing local issues. With the introduction of ISTEA in the 1990s, the Commission decided to adopt policies aimed at not just improving the traffic situation, but at reducing traffic congestion. It used the state travel model, MINUTP, to analyze traffic reduction proposals. The conclusions were to add new lanes and highways, such as the bypass option, which were found to be unsuccessful in reducing congestion. Charlottesville citizens were concerned about repeating this mistake- if building your way out of congestion has not worked in other areas, they asked, why should it work in ours?

Planners pointed out that tools to effectively study transportation alternatives and other local planning issues were in short supply. For example, when the Commission tried using MINUTP to find substitutes for the bypass, it found that it lacked sufficient detail to generate transit alternatives based on the population and employment data entered from the local land use plan. Another problem was that the land use stipulated in the existing plan was not dense enough to generate significant transit markets. Finally, the Commonwealth of Virginia was not interested in involving itself in local planning, so it was unwilling to fund a study of transportation alternatives. In light of these limitations, the Commission decided to apply for funding from the FHWA TCSP program to develop: 1) a 50-year vision for the study area which "brings together and builds upon established regional priorities for sustainability, economic development, environmental protections, transportation, and human services"; and 2) CorPlan, a simple, less data-intensive model that would address small city land use and transportation planning issues.

Definition of the Problem

The problem facing the Charlottesville region is rapid growth in and around a small city and the lack of a model to address the local land use and transportation impacts of that growth on suburban and rural areas of the region. Charlottesville is a fast growing area in Virginia, second only to Loudon County in the northern part of the state. CorPlan was designed to give local and regional planners a way to deal with the impacts of rapid growth by testing alternative land use ideas and providing outputs to be used in transportation models. It was designed to do this in a way that takes full advantage of the area's substantial public interest and involvement in local planning.

Project Goal

The project is still underway, but its goals are to develop a community-based model that:

• Is manageable
• Is not too data-intensive
• Uses existing software (e.g., Excel, Access, ArcView) and hardware
• Uses existing data sets (e.g., Census blocks)
• Uses pictures and diagrams to provide a visual depiction of community element types and land use scenarios
• Involves the public at all stages of development and uses their feedback to refine community elements and development goals

Ultimately, the Commission's goal is to use the model to develop alternative land use and transportation scenarios and identify how and when to influence regulations that affect local planning efforts for the purpose of achieving regional sustainable growth.

Top of Page

DISCUSSION OF THE MODEL

Introduction

CorPlan estimates regional land development potential using community elements (CEs) as its building blocks. Each element is defined by a quarter-mile diameter area and is illustrated by a photograph and plan diagram that convey its visual characteristics. The modelers wanted to define the CEs at a pedestrian scale, and they chose a quarter mile as the maximum distance for pedestrian accessibility. Each CE is given unique land use, infrastructure, and socioeconomic data. Local community input was used to identify and define the characteristics of CE types ranging from urban to rural. These units served as the foundation for modeling regional development scenarios. Results are used as inputs into a transportation model to estimate travel demand. Users can test alternative development scenarios by reassigning community elements. CorPlan is based on the concept that modes of transportation are highly dependent on land use choices. In other words, if you want transit, a certain development density of housing and commercial use is required.

With the model, the user estimates land development potential by defining subareas and assigning CEs to them. The subareas are either traffic analysis zones (TAZ) in and around Charlottesville or an aggregation of Census blocks further out (TAZs and Census block aggregations are used for calibration). CorPlan then calculates the development potential for each subarea by multiplying its net developable acreage by the data associated with its assigned CE. This is accomplished via a Microsoft Excel spreadsheet that is linked to ArcView GIS software. ArcView is able to easily create new polygons (subareas). To test alternative land development scenarios, the CEs and subareas can be reassigned and the model calculates new totals. All scenarios utilize the same estimates of future population and employment, but they differ in how they consume land. For example, a "dispersed" scenario would use more farm/forest acres than an "urban core" scenario. Consequently, the suggested transportation improvements also differ among scenarios.

The various steps in the CorPlan model are outlined below:

Step 1 - View Table of Contents

Step 2 - Review the Available Community Element Information

This includes the characteristics for each of the preset Charlottesville-area CEs, including the distribution of land uses, socioeconomic characteristics and key ratios (e.g., persons/household; # of units/building).

Step 3 - Review, Update, and/or Create Community Element Inventories

Each inventory includes land use types and associated land areas, building types and areas, roadway and parking areas, and socioeconomic ratios. Specific land use areas and socioeconomic totals are calculated based on user-entered data. Examples are:

• User enters number of single family dwelling units and the average floor area, and the spreadsheet calculates the total area occupied by all single-family dwellings.
• User enters the average number of floors and the model calculates the total building area.
• For each residential building type, user enters number of persons per dwelling unit and the model calculates the number of residents.
• For any given non-residential building type, user enters the ratio of employees per 1,000 square feet of gross building area and the model calculates the number of employees.

CorPlan also includes blank inventories that can be used to create additional CEs.

Step 4 - Enter Area Information

The total land area of each subarea is entered in the land use worksheet. The user can also enter specific land use data such as number of agricultural acres, number of commercial acres, and number of industrial acres. Using this information, the model calculates the amount of usable, developed, and vacant areas.

Step 5 - Enter Socioeconomic Information

This step is not required but highly recommended for model calibration and establishing a socioeconomic baseline for comparison. User enters data such as total employment, retail employment, school enrollment, total dwelling units, and population.

Step 6 - Enter Community Element Assumptions

Users define the mix of CEs for the base condition by entering the three-letter code (e.g., UMX for Urban Mixed Use) in the community element input worksheet. There are nineteen preset codes. The model then automatically calculates the base land use and socioeconomic conditions for that subarea. This worksheet also allows the user to create alternative scenarios by entering other three-letter codes and comparing the output to the base case.

Step 7 - Review Regional Summary

CorPlan presents information on three conditions: actual, base, and alternative. A summary of these three conditions tells the user how the region is proportioned among CEs under the base and alternative scenarios, and the actual, base, and alternative land use and socioeconomic totals.

Step 8 - Create and Review Alternative Scenarios

The user enters a unique name for the scenario and then modifies the CE codes for each subarea. Multiple alternatives can be entered and the model allows the user to compare among alternatives and to the existing and base conditions.

Relationship to and/or Incorporation of Travel Models

Before the CorPlan effort began, population and employment figures derived from existing local land use plans were input into the MINUTP model to generate travel demand data (the model uploads and generates socioeconomic data in the format needed by the MINUTP model). The problem was a coarse-grained land use plan, which did not support transit alternatives- key issues in the local planning process. CorPlan addresses this disparity by tying local land use with transportation; the model generates more fine-grained socioeconomic inputs for travel demand models with a local focus.

Data Inputs and Outputs

Data inputs to CorPlan are:

• Building footprint/land ratio
• Number of units, by building type (e.g., # of single family units, # of offices, # of government/institutional buildings)
• Average floor area, by building type

Required Area Inputs

• Usable area- the total area that is suitable for land development in each subarea. This area nets out land unfit for development because of environmental, historical, or policy reasons.
• Developed area- the amount of usable area currently developed (including area that is used for parks, public open space, agriculture and forestry).
• Vacant area- the amount of developable area that is not currently developed. This is the difference between usable area and developed area.
• Conversion factor- this factor converts the measurement units for the input data into acres. The Charlottesville area inputs are measured in square meters.

Land Use Categories (land use data must be translated into one of these categories, but specific definitions are up to the user)

• Single family residential
• Multifamily residential
• Offices
• Commercial retail
• Cultural/Civic
• Government/Institutional
• Industrial
• Common parking
• Streets/Right of Way
• Public Open Space
• Parks/playfields
• Agriculture/forest
• Vacant
• Permanently vacant
• Miscellaneous

Data outputs cover three categories of information: land use, infrastructure, and socioeconomic. These are listed below.

Land Use Distribution

• Single family
• Multifamily
• Offices
• Commercial retail
• Cultural/Civic
• Government/Institutional
• Industrial
• Common parking
• Streets
• Public open space
• Parks/playfields
• Agricultural/Forest

Socioeconomic

• Households
• Population
• Total employment
• Retail employment

Ratios

• Persons per household
• Workers per 1,000 sq.ft.
• Single family dwellings/acre
• Multifamily dwellings/acre
• Non-residential floor area ratio

GIS and Visualization Components

CorPlan is designed to work with or without the ArcView GIS software, but it is helpful to make community element assignments using ArcView. GIS allows the user to see, in map form:

• The average number of employees per acre and the average number of people per acre for all CEs.
• Each CE and subarea as unique color-coded areas.
• A window of summary statistics when a subarea is selected on the map.
• All subareas that contain a selected community type.
• The effect of various alternatives on the land use map.

It also uses photographs and plan graphics to help the public visualize a particular community element.

Top of Page

APPLICATION

The CorPlan model focuses on alternative land use scenarios, their transportation implications, and visioning techniques to generate results that reflect the concerns of the community.

Smart Growth/Growth Management

Land Use

During an Eastern District Planning Initiative workshop, the public was asked to provide feedback on both community and regional-level planning efforts. They were asked to create development scenarios that would meet regional goals based on themes that the team had identified during the planning process. It was conducted as a game show where the themes were named after old television shows. Planners plugged these results into the CorPlan model to formulate three alternative land use and transportation scenarios. The aim was to undertake an iterative process where the public evaluates each scenario and then the Advisory Committee discusses the responses.

The scenarios are designed to elicit reaction on two levels: 1) what the development option looks like on a regional scale; and 2) the associated transportation options. Planners tested various regional growth patterns to demonstrate that transportation options vary according to different density levels. Each of the land use and transportation scenarios is discussed below.

Scenario 1 - DISPERSED

This option can be referred to as the "suburbanization" scenario. It depicts what the region's development patterns would look like in the absence of directed planning efforts. Of the three choices, this one has the largest percentage of land assigned to suburban development. In addition, it devotes the smallest percentage of land to rural development, it has the smallest urban center, and there is no land set aside for the "enhanced suburban" community element. Its associated transportation plans are for a new expressway (bypass) around Charlottesville, adding new roads and/or widening many roads, and adding new greenways that traverse the region. The following percentages represent the resulting land use:

• Urban 0.6%
• Suburban 25.1%
• Enhanced Suburban 0.0%
• Rural 74.3%

Scenario 2 - NODAL

This option focuses on a few development centers (nodes). It significantly increases the rural community element portion and decreases the suburban portion compared to the Dispersed Scenario. It also increases the urban and enhanced suburban portions, albeit to a lesser degree. Its associated transportation plans are for adding and/or widening a few roads, adding express bus routes and rail/busways to serve Charlottesville and the surrounding nodes, and adding new greenways that traverse the region. The following percentages represent the resulting land use:

• Urban 0.9%
• Suburban 2.8%
• Enhanced Suburban 3.4%
• Rural 92.9%

Scenario 3 - URBAN CORE

This is the urban-centered option. It has the highest percentage of land devoted to urban and rural development, compared to the Dispersed and Nodal scenarios. Consequently, it has a very small percentage assigned to suburban or enhanced suburban development. Its associated transportation plans are for adding and/or widening some roads, adding express bus and rail/busways to serve Charlottesville and the surrounding nodes, and adding new greenways that traverse the region. The following percentages represent the resulting land use:

• Urban 4.1%
• Suburban 0.6%
• Enhanced Suburban 0.8%
• Rural 94.5%

The model's assumptions are as follows:

• None of the density levels exceed existing density in downtown Charlottesville.
• Mass transit in the Urban Core and Nodal scenarios would be combined with an urban street grid with one-mile connectors (one mile "spacing" of streets in the urban area).
• The dispersed scenario relies on roadways and includes a bypass around Charlottesville.
• Some land is "undevelopable" due to greenways, floodplains, eased land, etc.

Visioning/Public Participation

The CorPlan project team includes a wide range of participants: local, regional, and state staff, private sector transportation and land use planning consultants, and faculty from the University of Virginia. An appointed 42-member Citizen Advisory Committee hosted community workshops to guide the model's development, vision, and plan. The committee includes transportation and land use planners, artists, environmentalists, human services providers, realtors, developers, business people and advocates for the poor, elderly, and people with disabilities. Local citizens also had significant involvement: the workshops and presentations incorporated 150 people and a community survey targeted 1,200 households.

The most notable aspect of CorPlan is how the Commission chose to incorporate the public's views. Planners used the model to illustrate the public's perceived vision of the neighborhoods and asked them to discuss what they liked and did not like in terms of density, land use, and the street network. Participants felt that the model accurately portrayed the current feel of their neighborhoods and they offered suggestions for new community-level development characteristics. This information-gathering phase was the foundation for the model's community element concept. In the second set of public workshops, the planners asked participants to consider broader development patterns and take a more "birds-eye" view of their area. They asked them to clarify how they wanted future CEs to work as part of a unified group.

CorPlan uses neighborhood-level community elements that are described in terms understandable to the public and supplemented by photographs and clear diagrams. Citizens use the pictures and diagrams to compare the various development scenarios instead of having to rely on numbers to envision the results. This allows them to actually see what the alternatives would look like in their community and how individual CEs fit together to generate a regional plan. The process starts small by focusing on community elements that are circumscribed by the maximum pedestrian distance of one-quarter mile, and then it incrementally scales up into a regional plan.

Ease of Use/Replicability

The current version of CorPlan is available for download from the Thomas Jefferson District Planning Commission website. The model also uses readily available data sets, software, and hardware.

Key Findings and Implications

Beta versions of the model and user's manual were completed in March 2001. At this stage, the developers have made a few key discoveries:

• Local citizens, planners, and planning commissions have a higher than expected sense of what they want for their region.
• There was a surprising level of immediate support among local residents for the transit-oriented regional scenario.
• The challenge is not finding a common vision but about how to achieve that vision; the strategies should be politically and financially feasible. This means addressing citizens' desires while adhering to budgetary restrictions.
• The model development team found that it needed a flexible strategy for implementing transportation and land use plans- one that reflects the current political, demographic, and financial challenges facing the region.
• The Eastern Planning Initiative will aim to function as a springboard for meaningful dialogue about how the region wants to achieve its vision as times change.
• The 50-year time frame was found to be effective for several reasons:
  • It allows participants to be more imaginative about possible futures because they are not constrained by current policy, finance, technology, or demographic issues.
  • As a small region, it is possible to consider socioeconomic projections that are large enough to support significantly new transportation systems, especially mass transit.
  • It is easier to explain that the visioning process has to be considered over time as the local land use and transportation plans are updated.
  • It provides a long-term planning perspective.

Top of Page

CONCLUSIONS

Strengths of CorPlan

The CorPlan model has several strengths:

• It allows public participation from the beginning, in an easy to understand, visually appealing way.
• It allows for a more detailed approach by using community-level information.
• It uses existing data sets (e.g., Census tracts, land use).
• It is not too data intensive.
• It uses everyday language instead of planning jargon.
• It makes use of photographs and graphics to facilitate understanding.
• It uses readily available software and hardware.

Challenges/Limitations to CorPlan

There are also challenges and limitations to using the CorPlan model:

• It does not directly provide transportation, environment/social, or economic information, but this information can be derived from model outputs.
• Currently, it does not incorporate a public cost element so funding implications for transportation alternatives are not expressed.
• Like most models, it is a decision support tool, and ultimately, elected officials make land use decisions.

Future Goals

In the future, the software developers would like to include additional development scenarios and a module that determines the fiscal impacts of community elements. There is discussion about connecting CorPlan with community assessment and quality of life tools such as EPA's Smart Growth Index. The developers are trying to create a map overlay process that assigns CEs to defined areas in an effort to improve the topology and simplify modeling efforts. They may incorporate a transportation "threshold" concept, which would allow the user to see what transportation options are triggered by certain population levels. In addition, the developers are considering setting up an independent foundation to maintain the computer software and provide technical assistance to communities using it.

For more information on CorPlan go to the Thomas Jefferson Planning District Commission at www.TJPDC.org

Top of Page

GLOSSARY

Community Elements (CEs) - recognizable neighborhood-level planning entities, as defined by CorPlan. Community elements are the building blocks for the regional plan. Each one is defined by a quarter-mile diameter area and includes data on land use, infrastructure, socioeconomic characteristics, and the amount of developable land.

ESRI ArcView - a desktop geographic information system and mapping software from the ESRI company that provides data visualization, query, analysis, and integration capabilities along with the ability to create and edit geographic data. Currently, more than 500,000 copies are in use worldwide.

Floor Area Ratio (FAR) - the term used to describe the intensity of development on a unit of land; it is determined by dividing the gross floor area of all buildings on a lot by the area of that lot.

GIS (Geographic Information Systems) - a computer system that can spatially manage, analyze, and present geographic data tied to a particular location. A GIS combines layers of information about a place and allows the user to create customized maps and analyze patterns and relationships.

ISTEA (Intermodal Surface Transportation Efficiency Act of 1991) - Federal legislation designed to develop a national intermodal surface transportation system, to authorize funds for construction of highways, for highway safety programs, for mass transit programs, and for other purposes.

MINUTP- the Commonwealth of Virginia's transportation model.

One-mile Connectors - one-mile "spacing" of streets in the urban area.

Smart Growth - a planning policy that addresses suburban sprawl by concentrating growth in currently developed areas and increasing the use of alternative modes of transportation. It is aimed at minimizing haphazard development, preserving open space, and reducing traffic congestion, while maintaining property values and economic activity.

TEA-21 (Transportation Equity Act for the 21^st Century) - Federal legislation enacted in 1998 authorizing highway, highway safety, transit and other surface transportation programs for the next 6 years. TEA-21 builds on the initiatives established in ISTEA.

Traffic Analysis Zone (TAZ) - the smallest geographically designated area for analysis of transportation activity.

Usable Area - the total area that is suitable for land development in each subarea. This area nets out land unfit for development because of environmental, historical, or policy reasons.

Vacant Area - the amount of developable area that is not currently developed. This is the difference between usable area and developed area.

Vehicle Miles Traveled (VMT) - the amount of vehicle travel on a designated set of roadways multiplied by the total mileage of those roadways.

Zoning- the division of land into different types of uses to avoid nuisances and promote healthy and orderly development.

Top of Page

REFERENCES

Renaissance Planning Group, 2001, "Community-Based Planning," Volume 1, Issue 1, January.

Renaissance Planning Group, CorPlan User's Manual (Beta Version).

Thomas Jefferson Planning District Commission, 2001, "Jefferson Area Eastern Planning Initiative," Issue 3, January.

Thomas Jefferson Planning District Commission, 2000, "Jefferson Area Eastern Planning Initiative," Issues 1 and 2, April and August.

Contact: Thomas Jefferson Planning District Commission, Charlottesville, VA (434-979-7310 or http://www.tjpdc.org/)

Top of Page