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Case Study:
Albany, New York
Methodology
Calibration
RDS coefficients: The coefficients for the RDS equation are based on multivariate linear regression of Capital District residential growth between 1970 and 1990.
Travel time impedances: Travel time impedances for accessibility factors are based on gravity model friction factors from the CDTC's travel model.
Zone-specific calibration factors: To calibrate the model to regional employment and household forecasts, the following procedure is used:
- Run the model to allocate forecast (2015) growth under base year (1990) travel times, property taxes, property values, and developable land.
- Determine household and employment calibration factors for each zone. This is done using the ratio of the regional forecast growth by zone to the model's predicted growth increment by zone. This approach to calibration can save a significant amount of time, since it is not necessary to calibrating each of the equations used in the land use model.
- Re-run the model under future alternative scenarios (travel times, tax rates, etc.), with the calibration factors incorporated into the household and employment allocation equations.
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