Sensitivity Testing ¶
Overview ¶
Sensitivity testing evaluates whether ABM3 responds to changes in inputs and policies in a logical and defensible manner. Rather than testing model accuracy against observed data (which is the role of validation), sensitivity testing assesses the internal consistency and reasonableness of model behavior. A well-performing model should produce directionally correct and proportionally reasonable responses when key inputs are changed.
A broad range of sensitivity tests were conducted prior to using ABM3 for the 2025 Regional Plan.
Policy Sensitivity ¶
Policy sensitivity tests examine how the model responds to changes in travel demand management (TDM) strategies and pricing mechanisms. Tests include:
- Auto Operating Cost (AOC) increases — testing whether vehicle miles traveled (VMT) and mode shares respond appropriately to higher auto operating costs
- Parking pricing — evaluating shifts in mode choice and destination choice when parking costs increase in employment-dense areas
- Transit fare changes — assessing ridership sensitivity to fare increases and decreases
- Managed lane pricing — testing diversion between general purpose and tolled facilities
Land Use and Demographic Sensitivity ¶
These tests assess the model’s response to changes in the spatial distribution of population and employment, as well as shifts in household characteristics. Tests include:
- Household income shifts — examining changes in auto ownership, mode choice, and trip generation under higher and lower income distributions
- Employment density changes — testing whether trip attraction patterns respond appropriately to changes in job locations
- Transit-oriented development — evaluating mode share and VMT responses to increased density near transit stations
Other ¶
Several other tests were conducting to assess model response to teleworking levels, Electric Vehicle (EV) rebates, EV charging infrastructure, and microtransit service levels.