Free Parking Eligibility

The Free Parking Eligibility model predicts the availability of free parking at a person’s workplace. It is applied for people who work in zones that have parking charges, which are generally located in the Central Business Districts. The purpose of the model is to adequately reflect the cost of driving to work in subsequent models, particularly in mode choice.

Structure

• Configuration File: free_parking.yaml

• Core Table: persons

• Result Field: free_parking_at_work

This model generates only True or False outcomes, and is structured as a binary logit model.

Configuration

settings activitysim.abm.models.free_parking.FreeParkingSettings

Bases: LogitComponentSettings

Settings for the free_parking component.

Fields:

• COEFFICIENTS (pathlib.Path | None)

• CONSTANTS (dict[str, typing.Any])

• FREE_PARKING_ALT (int)

• LOGIT_TYPE (Literal['MNL', 'NL'])

• NESTS (activitysim.core.configuration.logit.LogitNestSpec | None)

• SPEC (pathlib.Path)

• preprocessor (activitysim.core.configuration.base.PreprocessorSettings | None)

• sharrow_skip (bool)

• source_file_paths (list[pathlib.Path])

Validators:

• nests_are_for_nl » NESTS

field COEFFICIENTS: Path | None = None

Coefficients filename.

This is a CSV file giving named parameters for use in the utility expression. If it is not provided, then it is assumed that all model coefficients are given explicitly in the SPEC as numerical values instead of named parameters. This is perfectly acceptable for use with ActivitySim for typical simulation applications, but may be problematic if used with “estimation mode”.

field CONSTANTS: dict[str, Any] = {}

Named constants usable in the utility expressions.

field FREE_PARKING_ALT: int [Required]

The code for free parking.

field LOGIT_TYPE: Literal['MNL', 'NL'] = 'MNL'

Logit model mathematical form.

• “MNL”

  Multinomial logit model.

• “NL”

  Nested multinomial logit model.

field NESTS: LogitNestSpec | None = None

Nesting structure for a nested logit model.

The nesting structure is specified heirarchically from the top, so the value of this field should be the “root” level nest of the nested logit tree, which should contain references to lower level nests and/or the actual alternatives.

For example, this YAML defines a simple nesting structure for four alternatives (DRIVE, WALK, WALK_TO_TRANSIT, DRIVE_TO_TRANSIT) with the two transit alternatives grouped together in a nest:

NESTS:
  name: root
  coefficient: coef_nest_root
  alternatives:
    - DRIVE
    - WALK
    - name: TRANSIT
      coefficient: coef_nest_transit
      alternatives:
      - WALK_TO_TRANSIT
      - DRIVE_TO_TRANSIT

Validated by:

• nests_are_for_nl

field SPEC: Path [Required]

Utility specification filename.

This is sometimes alternatively called the utility expressions calculator (UEC). It is a CSV file giving all the functions for the terms of a linear-in-parameters utility expression.

field preprocessor: PreprocessorSettings | None = None

Setting for the preprocessor.

field sharrow_skip: bool = False

Skip sharrow when evaluating this component.

field source_file_paths: list[Path] = None

A list of source files from which these settings were loaded.

This value should not be set by the user within the YAML settings files, instead it is populated as those files are loaded. It is primarily provided for debugging purposes, and does not actually affect the operation of any model.

validator nests_are_for_nl  »  NESTS

Checks that nests are provided if (and only if) LOGIT_TYPE is NL.

Examples

• Prototype MTC

• Prototype ARC

Implementation

activitysim.abm.models.free_parking.free_parking(state: State, persons_merged: DataFrame, persons: DataFrame, model_settings: Optional[FreeParkingSettings] = None, model_settings_file_name: str = 'free_parking.yaml', trace_label: str = 'free_parking') → None

Determine for each person whether they have free parking available at work.

Parameters:

stateworkflow.State

persons_mergedDataFrame

This represents the ‘choosers’ table for this component.

personsDataFrame

The original persons table is referenced so the free parking column can be appended to it.

model_settingsFreeParkingSettings, optional

The settings used in this model component. If not provided, they are loaded out of the configs directory YAML file referenced by the model_settings_file_name argument.

model_settings_file_namestr, default “free_parking.yaml”

This is where model setting are found if model_settings is not given explicitly. The same filename is also used to write settings files to the estimation data bundle in estimation mode.

trace_labelstr, default “free_parking”

This label is used for various tracing purposes.