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This wiki is intended to serve as a user guide to describe the overall structure of the SanVE modeling system, model set up and running procedures, and the model system inputs and outputs. Additionally, this wiki demonstrates the visualization tool developed for the model.
SanVE is a custom implementation of VisionEval, a programming framework for disaggregate strategic planning models. To learn more about VisionEval, please visit the project Website, including the System Design. There are three models available in VisionEval: VERPAT, VERSPM, and VEState. SanVE focuses on the SANDAG version of VERSPM (SDRSPM).
VERSPM is a strategic planning model that assists state and metropolitan area planners with the evaluation of transportation and land use policy scenarios. It considers a large number of factors that affect the performance of transportation systems and their effects on people and the environment.
- Changes in population demographics (age structure).
- Changes in personal income.
- Relative amounts of development occurring in metropolitan, urban and rural areas.
- Metropolitan, other urban, and rural area densities.
- Urban form in metropolitan areas (proportion of population living in mixed-use areas with a well-interconnected street and walkway system).
- Amounts of metropolitan area transit service.
- Metropolitan freeway and arterial supplies.
- Auto and light truck proportions by year.
- Average vehicle fuel economy by vehicle type and year.
- Vehicle age distribution by vehicle type.
- Electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs)
- Light-weight vehicles such as bicycles, electric bicycles, electric scooters, etc.
- Pricing -- fuel, vehicle miles traveled (VMT), parking.
- Demand management -- employer-based and individual marketing.
- Car-sharing.
- Effects of congestion on fuel economy.
- Effects of incident management on fuel economy.
- Vehicle operation and maintenance -- eco-driving, low rolling resistance tires, speed limits.
- Carbon intensity of fuels, including the well-to-wheels emissions.
- Carbon production from the electric power that is generated to run electric vehicles.
VERSPM is a disaggregate policy model that predicts travel demand impacts at an individual household level. The model estimates vehicle ownership, vehicle travel, fuel consumption, and GHG emissions at the individual household level. This structure accounts for the synergistic and antagonistic effects of multiple policies and factors (e.g., gas prices) on vehicle travel and emissions. For example, the battery range of electric vehicles (EVs) and plug‐in hybrid electric vehicles (PHEVs) is less of an issue for households residing in compact mixed‐use neighborhoods because those households tend to drive fewer miles each day. Modeling at the household level makes it possible to evaluate the relationships between travel, emissions and the characteristics of households, land use, transportation systems, vehicles, and other factors. In addition, household level analysis makes it possible to evaluate the equitability of the costs and benefits of different strategies.
The model comprises sequential steps with feedback. Each calculation step is composed of a number of calculations that operate on the results of the previous calculation step and on input data that reflect inputs.
The RSPM steps are grouped as follows:
- Define households.
- Characterize vehicles.
- Calculate VMT.
- Balance VMT with travel costs.
The iterative process to balance the VMT with travel costs allows congestion and other costs introduced at this step influence the amount of travel. This step balances the amount of household travel with the cost of travel and recalculates household VMT, Fuel & GHG in the process. The primary outputs of the RSPM are household travel, fuel, and power consumption, and GHG emissions calculations, but other information is produced for households and commercial vehicles as well. The amount of commercial (light‐duty) and freight (heavy duty) travel is calculated as well as associated fuel, power consumption and GHG emissions for those vehicles.