UrbanSim is a software-based system designed to be used for integrated planning and analysis of urban development, incorporating the interactions between land use, transportation, and public policy. It is designed to interface to existing travel modeling procedures, including both current four-step as well as newer activity-based travel models. It is currently being extended to address environmental impacts of development by simulating land cover, water demand and nutrient emissions. Specifically, the model:
* Simulates the key decision makers and choices impacting urban development; in particular, the mobility and location choices of households and businesses, and the development choices of developers;
* Explicitly accounts for land, structures (houses and commercial buildings), and occupants (households and businesses);
* Simulates urban development as a dynamic process over time and space, as opposed to a cross-sectional or equilibrium approach;
* Simulates the land market as the interaction of demand (locational preferences of businesses and households) and supply (existing vacant space, new construction, and redevelopment), with prices adjusting in response to short-term imbalances between supply and demand (vacancy rates);
* Incorporates governmental policy assumptions explicitly, and evaluates policy impacts by modeling market response;
* Is designed for high levels of spatial and activity disaggregation, currently using a 150 meter grid; and
* Addresses both greenfield development and redevelopment or intensification.
UrbanSim
Submitted by admin on Mon, 06/04/2007 - 3:11pm.
Developers:
Paul Waddell: model design and project lead<BR>Michael Noth, Alan Borning: software architecture<BR>
Website:
www.urbansim.org
Email:
pwaddell@u.washington.edu
Strengths:
• Dynamic behavioral foundation is used that makes the model more transparent and explainable to users and decision-makers; reflects real-world processes that make the model easier to evolve and to interface to other process models such as environmental models.
• High degree of spatial resolution: Currently uses spatial grid of 150 meters for interface with environmental models such as land cover.
• Model and source code are entirely open source: They are freely available for use and modification, and can be downloaded from the web site. This is intended to facilitate collaborative use and further development.
• A visualization component has been designed into the model architecture, and is now operational. This provides integrated 2 and 3-dimensional mapping, in addition to charts and graphs for interpreting and comparing model results, and for diagnosis during model development and testing.
Outputs:
All outputs are currently by zone, but can be made available at parcel or grid cell level.
User Input Requirements:
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Time Commitment:
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Data Input Requirements:
ArcView shape files: Parcels; Environmentally sensitive layers; e.g. wetlands, floodplains, high slopes, fault zones; and Urban Growth Boundaries or other policy boundaries; Zones used in travel modeling.
ASCII data: Business establishments; Household data from Census (STF3A and PUMS); Travel impedance from travel models (peak times and logsums).
Equipment Needs:
UrbanSim requires a 333 MHz or higher computer with 128 MB of RAM, 2+ GBs of free hard drive space (can be less depending on study area grid resolution). It runs on Windows 95/98, Windows NT 4.0/2000, Linux or UNIX, using Java JKD 1.3.
Limitations:
• The model currently has high data requirements; data mining and synthetic data cleaning tools are currently being designed to facilitate working with messy data.
• The model has been recently developed, so experience is limited to current applications in Hawaii, Oregon, Utah and Washington.
• The model is being rapidly evolved, with the first major release based on a complete redesign of the software architecture in the second quarter, 2000.
Staff Requirements:
Calibration of the model requires knowledge of statistical software to perform multiple regression and logit model estimation using external econometric software such as Alogit or Limdep. Further work on calibration tools may make the use of external software unnecessary in the future. Use of the model requires land-use and transportation planning expertise and general computer experience. The user interface for the model is intended for relatively non-technical users.
Software Cost:
None - may be downloaded for free at http://www.urbansim.org/.
Preview:
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Maintenance Costs:
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