Examples#
This page describes the example models included with ActivitySim. There are three basic types of example model:
“production” examples are calibrated and validated by the relevant agency, and are intended to be replicas of an “official” travel model used by that agency, although generally we expect agencies to maintain independent repositories and not rely on the Consortium maintained version as a single source for the model. At this time there are no production examples in the consortium’s collection, but we expect that to change soon.
“prototype” examples are not representative of any “official” travel model used by the relevant agency, but they are viewed as “ok” models by the consortium: they are usually at least loosely calibrated and/or validated, and typically contain at least some components or parameters specialized for the relevant region. They may be in-development models that are not quite finished, or consortium maintained models that are derived from but now different from the official model of some region. They should not be used in place of “official” models for policy analysis in any given region, but could serve as a donor model for new users who want to implement ActivitySim somewhere new (subject to all the caveats that go along with transferring models).
“placeholder” examples are computational testbeds that technically run but have not been calibrated nor validated in any meaningful way. These examples are early stage development models used for testing purposes, and users are strongly cautioned not to use them for any policy or planning purpose.
The current examples are:
Example |
Purpose |
Zone Systems |
Status |
---|---|---|---|
Original ActivitySim Example, derived from MTC TM1 |
1 |
Mature |
|
Prototype MTC example with additional optional models |
1 |
In development |
|
Estimation example with prototype_mtc |
1 |
Mature |
|
2 or 3 zone system example using MTC data |
2 or 3 |
Simple test example |
|
3 zone system example using Marin tour mode choice model |
3 |
Mature |
|
ARC agency example |
1 |
In development |
|
SEMCOG agency example |
1 |
In development |
|
PSRC agency example |
2 |
Future development |
|
SANDAG agency example |
3 |
Future development |
|
SANDAG agency example |
3 |
In development |
|
MWCOG agency example |
2 |
In development |
Note
The example_manifest.yaml contains example commands to create and run several versions of the examples. See also Adding Agency Examples for more information on agency example models.
prototype_mtc#
The initial example implemented in ActivitySim was prototype_mtc. This section described the prototype_mtc model design, how to setup and run the example, and how to review outputs. The default configuration of the example is limited to a small sample of households and zones so that it can be run quickly and require less than 1 GB of RAM. The full scale example can be configured and run as well.
Model Design#
The prototype_mtc example is based on (but has evolved away from) the Bay Area Metro Travel Model One (TM1). TM1 has its roots in a wide array of analytical approaches, including discrete choice forms (multinomial and nested logit models), activity duration models, time-use models, models of individual micro-simulation with constraints, entropy-maximization models, etc. These tools are combined in the model design to realistically represent travel behavior, adequately replicate observed activity-travel patterns, and ensure model sensitivity to infrastructure and policies. The model is implemented in a micro-simulation framework. Microsimulation methods capture aggregate outcomes through the representation of the behavior of individual decision-makers.
Space#
The prototype MTC model uses the 1454 TAZ zone system developed for the MTC trip-based model. The zones are fairly large for the region, which may somewhat distort the representation of transit access in mode choice. To ameliorate this problem, the original model zones were further sub-divided into three categories of transit access: short walk, long walk, and not walkable. However, support for transit subzones is not included in the activitysim implementation since the latest generation of activity-based models typically use an improved approach to spatial representation called multiple zone systems. See placeholder_multiple_zone for more information.
Decision-making units#
Decision-makers in the model system are households and persons. These decision-makers are created for each simulation year based on a population synthesis process such as PopulationSim. The decision-makers are used in the subsequent discrete-choice models to select a single alternative from a list of available alternatives according to a probability distribution. The probability distribution is generated from various logit-form models which take into account the attributes of the decision-maker and the attributes of the various alternatives. The decision-making unit is an important element of model estimation and implementation, and is explicitly identified for each model.
Person type segmentation#
TM1 is implemented in a micro-simulation framework. A key advantage of the micro-simulation approach is that there are essentially no computational constraints on the number of explanatory variables which can be included in a model specification. However, even with this flexibility, the model system includes some segmentation of decision-makers. Segmentation is a useful tool both to structure models and also as a way to characterize person roles within a household.
The person types shown below are used for the example model. The person types are mutually exclusive with respect to age, work status, and school status.
Person Type Code |
Person Type |
Age |
Work Status |
School Status |
---|---|---|---|---|
1 |
Full-time worker (30+ hours a week) |
18+ |
Full-time |
None |
2 |
Part-time worker (<30 hours but works on a regular basis) |
18+ |
Part-time |
None |
3 |
College student |
18+ |
Any |
College |
4 |
Non-working adult |
18 - 64 |
Unemployed |
None |
5 |
Retired person |
65+ |
Unemployed |
None |
6 |
Driving age student |
16 - 17 |
Any |
Pre-college |
7 |
Non-driving student |
6 - 16 |
None |
Pre-college |
8 |
Pre-school child |
0 - 5 |
None |
Preschool |
Household type segments are useful for pre-defining certain data items (such as destination choice size terms) so that these data items can be pre-calculated for each segment. Precalculation of these data items reduces model complexity and runtime. The segmentation is based on household income, and includes four segments - low, medium, high, very high.
In the model, the persons in each household are assigned a simulated but fixed value of time that modulates the relative weight the decision-maker places on time and cost. The probability distribution from which the value of time is sampled was derived from a toll choice model estimated using data from a stated preference survey performed for the SFCTA Mobility, Access, and Pricing Study, and is a lognormal distribution with a mean that varies by income segment.
Activity type segmentation#
The activity types are used in most model system components, from developing daily activity patterns and to predicting tour and trip destinations and modes by purpose. The set of activity types is shown below. The activity types are also grouped according to whether the activity is mandatory or non-mandatory and eligibility requirements are assigned determining which person-types can be used for generating each activity type. The classification scheme of each activity type reflects the relative importance or natural hierarchy of the activity, where work and school activities are typically the most inflexible in terms of generation, scheduling and location, and discretionary activities are typically the most flexible on each of these dimensions. Each out-of-home location that a person travels to in the simulation is assigned one of these activity types.
Purpose |
Description |
Classification |
Eligibility |
---|---|---|---|
Work |
Working at regular workplace or work-related activities outside the home |
Mandatory |
Workers and students |
University |
College or university |
Mandatory |
Age 18+ |
High School |
Grades 9-12 |
Mandatory |
Age 14-17 |
Grade School |
Grades preschool, K-8 |
Mandatory |
Age 0-13 |
Escorting |
Pick-up/drop-off passengers (auto trips only) |
NonMandatory |
Age 16+ |
Shopping |
Shopping away from home |
NonMandatory |
Age 5+ (if joint travel, all persons) |
Other Maintenance |
Personal business/services and medical appointments |
NonMandatory |
Age 5+ (if joint travel, all persons) |
Social/Recreational |
Recreation, visiting friends/family |
NonMandatory |
Age 5+ (if joint travel, all persons) |
Eat Out |
Eating outside of home |
NonMandatory |
Age 5+ (if joint travel, all persons) |
Other Discretionary |
Volunteer work, religious activities |
NonMandatory |
Age 5+ (if joint travel, all persons) |
Treatment of time#
The TM1 example model system functions at a temporal resolution of one hour. These one hour increments begin with 3 AM and end with 3 AM the next day. Temporal integrity is ensured so that no activities are scheduled with conflicting time windows, with the exception of short activities/tours that are completed within a one hour increment. For example, a person may have a short tour that begins and ends within the 8 AM to 9 AM period, as well as a second longer tour that begins within this time period, but ends later in the day.
A critical aspect of the model system is the relationship between the temporal resolution used for scheduling activities and the temporal resolution of the network assignment periods. Although each activity generated by the model system is identified with a start time and end time in one hour increments, LOS matrices are only created for five aggregate time periods. The trips occurring in each time period reference the appropriate transport network depending on their trip mode and the mid-point trip time. The definition of time periods for LOS matrices is given below.
Time Period |
Start Hour |
---|---|
EA |
3 |
AM |
5 |
MD |
9 |
PM |
14 |
EV |
18 |
Trip modes#
The trip modes defined in the example model are below. The modes include auto by occupancy and toll/non-toll choice, walk and bike, walk and drive access to five different transit line-haul modes, and ride hail with taxi, single TNC (Transportation Network Company), and shared TNC.
Auto
SOV Free
SOV Pay
2 Person Free
2 Person Pay
3+ Person Free
3+ Person Pay
Nonmotorized
Walk
Bike
Transit
Walk
Walk to Local Bus
Walk to Light-Rail Transit
Walk to Express Bus
Walk to Bus Rapid Transit
Walk to Heavy Rail
Drive
Drive to Local Bus
Drive to Light-Rail Transit
Drive to Express Bus
Drive to Bus Rapid Transit
Drive to Heavy Rail
Ride Hail
Taxi
Single TNC
Shared TNC
Sub-models#
The general design of the prototype_mtc model is presented below. Long-term choices that relate to the usual workplace/university/school for each worker and student, household car ownership, and the availability of free parking at workplaces are first.
The coordinated daily activity pattern type of each household member is the first travel-related sub-model in the hierarchy. This model classifies daily patterns by three types:
Mandatory, which includes at least one out-of-home mandatory activity (work or school)
Non-mandatory, which includes at least one out-of-home non-mandatory activity, but does not include out-of-home mandatory activities
Home, which does not include any out-of-home activity or travel
The pattern type sub-model leaves open the frequency of tours for mandatory and nonmandatory purposes since these sub-models are applied later in the model sequence. Daily pattern-type choices of the household members are linked in such a way that decisions made by members are reflected in the decisions made by the other members.
After the frequency and time-of-day for work and school tours are determined, the next major model component relates to joint household travel. This component produces a number of joint tours by travel purpose for the entire household, travel party composition in terms of adults and children, and then defines the participation of each household member in each joint household tour. It is followed by choice of destination and time-ofday.
The next stage relates to maintenance and discretionary tours that are modeled at the individual person level. The models include tour frequency, choice of destination and time of day. Next, a set of sub-models relate tour-level details on mode, exact number of intermediate stops on each half-tour and stop location. It is followed by the last set of sub-models that add details for each trip including trip departure time, trip mode details and parking location for auto trips.
The output of the model is a disggregate table of trips with individual attributes for custom analysis. The trips can be aggregated into travel demand matrices for network loading.
Setup#
The following describes the prototype_mtc model setup.
Folder and File Setup
The prototype_mtc has the following root folder/file setup:
configs - settings, expressions files, etc.
configs_mp - override settings for the multiprocess configuration
data - input data such as land use, synthetic population files, and network LOS / skims
output - outputs folder
Inputs#
In order to run prototype_mtc, you first need the input files in the data
folder as identified in the configs\settings.yaml
file and the configs\network_los.yaml
file:
input_table_list: the input CSV tables for MTC (see below for column definitions):
households - Synthetic population household records for a subset of zones.
persons - Synthetic population person records for a subset of zones.
land_use - Zone-based land use data (population and employment for example) for a subset of zones.
taz_skims: skims.omx - an OMX matrix file containing the MTC TM1 skim matrices for a subset of zones. The time period for the matrix must be represented at the end of the matrix name and be seperated by a double_underscore (e.g. BUS_IVT__AM indicates base skim BUS_IVT with a time period of AM).
These files are used in the tests as well. The full set of MTC households, persons, and OMX skims are on the ActivitySim resources repository.
Additional details on these files is available in the original Travel Model 1 repository, although many of the files described there are not used in ActivitySim.
Households#
The households table contains the following synthetic population columns:
household_id: numeric ID of this household, used in persons table to join with household characteristics
TAZ: zone where this household lives
income: Annual household income, in 2000 dollars
hhsize: Household size
HHT: Household type (see below)
auto_ownership: number of cars owned by this household (0-6)
num_workers: number of workers in the household
sample_rate
Household types#
These are household types defined by the Census Bureau and used in ACS table B11001.
Code |
Description |
---|---|
0 |
None |
1 |
Married-couple family |
2 |
Male householder, no spouse present |
3 |
Female householder, no spouse present |
4 |
Nonfamily household, male alone |
5 |
Nonfamily household, male not alone |
6 |
Nonfamily household, female alone |
7 |
Nonfamily household, female not alone |
Persons#
This table describes attributes of the persons that constitute each household. This file contains the following columns:
person_id: Unique integer identifier for each person. This value is globally unique, i.e. no two individuals have the same person ID, even if they are in different households.
household_id: Household identifier for this person, foreign key to households table
age: Age in years
PNUM: Person number in household, starting from 1.
sex: Sex, 1 = Male, 2 = Female
pemploy: Employment status (see below)
pstudent: Student status (see below)
ptype: Person type (see person type segmentation above)
Employment status#
Code |
Description |
---|---|
1 |
Full-time worker |
2 |
Part-time worker |
3 |
Not in labor force |
4 |
Student under 16 |
Student status#
Code |
Description |
---|---|
1 |
Preschool through Grade 12 student |
2 |
University/professional school student |
3 |
Not a student |
Land use#
All values are raw numbers and not proportions of the total.
TAZ: Zone which this row describes
DISTRICT: Superdistrict where this TAZ is (34 superdistricts in the Bay Area)
SD: Duplicate of DISTRICT
COUNTY: County within the Bay Area (see below)
TOTHH: Total households in TAZ
TOTPOP: Total population in TAZ
TOTACRE: Area of TAZ, acres
RESACRE: Residential area of TAZ, acres
CIACRE: Commercial/industrial area of TAZ, acres
TOTEMP: Total employment
AGE0519: Persons age 5 to 19 (inclusive)
RETEMPN: NAICS-based total retail employment
FPSEMPN: NAICS-based financial and professional services employment
HEREMPN: NAICS-based health, education, and recreational service employment
AGREMPN: NAICS-based agricultural and natural resources employment
MWTEMPN: NAICS-based manufacturing and wholesale trade employment
OTHEMP: NAICS-based other employment
PRKCST: Hourly cost paid by long-term (8+ hours) parkers, year 2000 cents
OPRKCST: Hourly cost paid by short term parkers, year 2000 cents
area_type: Area type designation (see below)
HSENROLL: High school students enrolled at schools in this TAZ
COLLFTE: College students enrolled full-time at colleges in this TAZ
COLLPTE: College students enrolled part-time at colleges in this TAZ
TERMINAL: Average time to travel from automobile storage location to origin/destination (floating-point minutes)
Counties#
Code |
Name |
---|---|
1 |
San Francisco |
2 |
San Mateo |
3 |
Santa Clara |
4 |
Alameda |
5 |
Contra Costa |
6 |
Solano |
7 |
Napa |
8 |
Sonoma |
9 |
Marin |
Area types#
Code |
Description |
---|---|
0 |
Regional core |
1 |
Central business district |
2 |
Urban business |
3 |
Urban |
4 |
Suburban |
5 |
Rural |
Note
ActivitySim can optionally build an HDF5 file of the input CSV tables for use in subsequent runs since HDF5 is binary and therefore results in faster read times. see Configuration
OMX and HDF5 files can be viewed with the OMX Viewer or HDFView.
The other_resources\scripts\build_omx.py
script will build one OMX file containing all the skims. The original MTC TM1 skims were converted for the prototype from
Cube to OMX using the other_resources\scripts\mtc_tm1_omx_export.s
script.
The prototype_mtc_sf inputs were created by the other_resources\scripts\create_sf_example.py
script, which creates the land use, synthetic population, and
skim inputs for a subset of user-defined zones.
Configuration#
This section has been moved to Configuration.
Sub-Model Specification Files#
Included in the configs
folder are the model specification files that store the
Python/pandas/numpy expressions, alternatives, and other settings used by each model. Some models includes an
alternatives file since the alternatives are not easily described as columns in the expressions file. An example
of this is the non_mandatory_tour_frequency_alternatives.csv
file, which lists each alternative as a row and each
columns indicates the number of non-mandatory tours by purpose. The set of files for the prototype_mtc are below. The
prototype_arc, prototype_semcog, and prototype_mtc_extended examples added additional submodels.
Model |
Specification Files |
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Pipeline#
The models
setting contains the specification of the data pipeline model steps, as shown below:
models:
- initialize_landuse
- compute_accessibility
- initialize_households
- school_location
- workplace_location
- auto_ownership_simulate
- free_parking
- cdap_simulate
- mandatory_tour_frequency
- mandatory_tour_scheduling
- joint_tour_frequency
- joint_tour_composition
- joint_tour_participation
- joint_tour_destination
- joint_tour_scheduling
- non_mandatory_tour_frequency
- non_mandatory_tour_destination
- non_mandatory_tour_scheduling
- tour_mode_choice_simulate
- atwork_subtour_frequency
- atwork_subtour_destination
- atwork_subtour_scheduling
- atwork_subtour_mode_choice
- stop_frequency
- trip_purpose
- trip_destination
- trip_purpose_and_destination
- trip_scheduling
- trip_mode_choice
- write_data_dictionary
- track_skim_usage
- write_trip_matrices
- write_tables
These model steps must be registered Inject steps, as noted below. If you provide a resume_after
argument to activitysim.core.pipeline.run()
the pipeliner will load checkpointed tables from the checkpoint store
and resume pipeline processing on the next model step after the specified checkpoint.
resume_after = None
#resume_after = 'school_location'
The model is run by calling the activitysim.core.pipeline.run()
method.
pipeline.run(models=_MODELS, resume_after=resume_after)
Running the example#
To run the example, do the following:
Activate the correct conda environment if needed
View the list of available examples
activitysim create --list
Create a local copy of an example folder
activitysim create --example prototype_mtc --destination my_test_example
Run the example
cd my_test_example
activitysim run -c configs -d data -o output
ActivitySim will log progress and write outputs to the output folder.
The example should run in a few minutes since it runs a small sample of households.
Note
A customizable run script for power users can be found in the Github repo.
This script takes many of the same arguments as the activitysim run
command, including paths to
--config
, --data
, and --output
directories. The script looks for these folders in the current
working directory by default.
python simulation.py
Multiprocessing#
The model system is parallelized via Multiprocessing. To setup and run the Examples using
multiprocessing, follow the same steps as the above Running the example, but add an additional -c
flag to
include the multiprocessing configuration settings via settings file inheritance (see Command Line Interface) as well:
activitysim run -c configs_mp -c configs -d data -o output
The multiprocessing example also writes outputs to the output folder.
The default multiprocessed example is configured to run with two processors and chunking training: num_processes: 2
,
chunk_size: 0
, and chunk_training_mode: training
. Additional more performant configurations are included and
commented out in the example settings file. For example, the 100 percent sample full scale multiprocessing example
- prototype_mtc_full
- was run on a Windows Server machine with 28 cores and 256GB RAM with the configuration below.
The default setup runs with chunk_training_mode: training
since no chunk cache file is present. To run the example
significantly faster, try chunk_training_mode: disabled
if the machine has sufficient RAM, or try
chunk_training_mode: production
. To configure chunk_training_mode: production
, first configure chunking as
discussed below. See Multiprocessing and Chunk for more information.
households_sample_size: 0
num_processes: 24
chunk_size: 0
chunk_training_mode: production
Configuring chunking#
To configure chunking, ActivitySim must first be trained to determine reasonable chunking settings given the model setup and machine. The steps to configure chunking are:
Run the full scale model with
chunk_training_mode: training
. Setnum_processors
to about 80% of the available physical processors andchunk_size
to about 80% of the available RAM. This will run the model and create thechunk_cache.csv
file in the outputcache directory for reuse.The
households_sample_size
for training chunking should be at least 1 / num_processors to provide sufficient data for training and thechunk_method: hybrid_uss
typically performs best.Run the full scale model with
chunk_training_mode: production
. Experiment with differentnum_processors
andchunk_size
settings depending on desired runtimes and machine resources.
See Chunk for more information. Users can run chunk_training_mode: disabled
if the machine has an abundance of RAM for the model setup.
Outputs#
The key output of ActivitySim is the HDF5 data pipeline file outputs\pipeline.h5
. By default, this datastore file
contains a copy of each data table after each model step in which the table was modified.
The example also writes the final tables to CSV files by using the write_tables
step. This step calls
activitysim.core.pipeline.get_table()
to get a pandas DataFrame and write a CSV file for each table
specified in output_tables
in the settings.yaml file.
output_tables:
h5_store: False
action: include
prefix: final_
tables:
- checkpoints
- accessibility
- land_use
- households
- persons
- tours
- trips
- joint_tour_participants
The other_resources\scripts\make_pipeline_output.py
script uses the information stored in the pipeline file to create
the table below for a small sample of households. The table shows that for each table in the pipeline, the number of rows
and/or columns changes as a result of the relevant model step. A checkpoints
table is also stored in the
pipeline, which contains the crosswalk between model steps and table states in order to reload tables for
restarting the pipeline at any step.
Table |
Creator |
NRow |
NCol |
---|---|---|---|
accessibility |
compute_accessibility |
1454 |
10 |
households |
initialize |
100 |
65 |
households |
workplace_location |
100 |
66 |
households |
cdap_simulate |
100 |
73 |
households |
joint_tour_frequency |
100 |
75 |
joint_tour_participants |
joint_tour_participation |
13 |
4 |
land_use |
initialize_landuse |
1454 |
44 |
person_windows |
initialize_households |
271 |
21 |
persons |
initialize_households |
271 |
42 |
persons |
school_location |
271 |
45 |
persons |
workplace_location |
271 |
52 |
persons |
free_parking |
271 |
53 |
persons |
cdap_simulate |
271 |
59 |
persons |
mandatory_tour_frequency |
271 |
64 |
persons |
joint_tour_participation |
271 |
65 |
persons |
non_mandatory_tour_frequency |
271 |
74 |
school_destination_size |
initialize_households |
1454 |
3 |
school_modeled_size |
school_location |
1454 |
3 |
tours |
mandatory_tour_frequency |
153 |
11 |
tours |
mandatory_tour_scheduling |
153 |
15 |
tours |
joint_tour_composition |
159 |
16 |
tours |
tour_mode_choice_simulate |
319 |
17 |
tours |
atwork_subtour_frequency |
344 |
19 |
tours |
stop_frequency |
344 |
21 |
trips |
stop_frequency |
859 |
7 |
trips |
trip_purpose |
859 |
8 |
trips |
trip_destination |
859 |
11 |
trips |
trip_scheduling |
859 |
11 |
trips |
trip_mode_choice |
859 |
12 |
workplace_destination_size |
initialize_households |
1454 |
4 |
workplace_modeled_size |
workplace_location |
1454 |
4 |
Logging#
Included in the configs
folder is the logging.yaml
, which configures Python logging
library. The following key log files are created with a model run:
activitysim.log
- overall system log filetiming_log.csv
- submodel step runtimesomnibus_mem.csv
- multiprocessed submodel memory usage
Refer to the Tracing section for more detail on tracing.
Trip Matrices#
The write_trip_matrices
step processes the trips table to create open matrix (OMX) trip matrices for
assignment. The matrices are configured and coded according to the expressions in the model step
trip annotation file. See Write Trip Matrices for more information.
Tracing#
There are two types of tracing in ActivtiySim: household and origin-destination (OD) pair. If a household trace ID is specified, then ActivitySim will output a comprehensive set (i.e. hundreds) of trace files for all calculations for all household members:
Several CSV files
- each input, intermediate, and output data table - chooser, expressions/utilities, probabilities, choices, etc. - for the trace household for each sub-model
If an OD pair trace is specified, then ActivitySim will output the acessibility calculations trace file:
accessibility.result.csv
- accessibility expression results for the OD pair
With the set of output CSV files, the user can trace ActivitySim calculations in order to ensure they are correct and/or to help debug data and/or logic errors.
Writing Logsums#
The tour and trip destination and mode choice models calculate logsums but do not persist them by default. Mode and destination choice logsums are essential for re-estimating these models and can therefore be saved to the pipeline if desired. To save the tour and trip destination and mode choice model logsums, include the following optional settings in the model settings file. The data is saved to the pipeline for later use.
# in workplace_location.yaml for example
DEST_CHOICE_LOGSUM_COLUMN_NAME: workplace_location_logsum
DEST_CHOICE_SAMPLE_TABLE_NAME: workplace_location_sample
# in tour_mode_choice.yaml for example
MODE_CHOICE_LOGSUM_COLUMN_NAME: mode_choice_logsum
The DEST_CHOICE_SAMPLE_TABLE_NAME contains the fields in the table below. Writing out the destination choice sample table, which includes the mode choice logsum for each sampled alternative destination, adds significant size to the pipeline. Therefore, this feature should only be activated when writing logsums for a small set of households for model estimation.
Field |
Description |
---|---|
chooser_id |
chooser id such as person or tour id |
alt_dest |
destination alternative id |
prob |
alternative probability |
pick_count |
sampling with replacement pick count |
mode_choice_logsum |
mode choice logsum |
prototype_mtc_extended#
prototype_mtc_extended contains additional models that were developed to enhance ActivitySim’s modeling capabilities. This example inherets the data and configuration files from prototype_mtc. The current list of additional models included in this example are:
Vehicle Type Choice: Selects a vehicle type for each household vehicle. Runs after auto_ownership.
Vehicle Allocation: Allocates a vehicle for each tour and each occupancy level. Tour and trip mode choice auto operating costs are modified to reflect the allocated vehicle option.
School Escorting: Explicitly models school drop-off / pick-up of students to and from school.
The prototype_mtc_extended example also contains changes to test the flexible number of tour and trip ids. (Information in why this is important can be found here.) The following changes were made to demonstrate this:
An additional alternative was added to the non-mandatory tour frequency alternatives file containing 2 other discretionary tours.
An additional alternative was added to the stop_frequency_alts.csv for 4 outbound stops and 3 inbound stops. This alternative was then included as part of the stop_frequency_othdiscr.csv specification with an added calibration constant to control that alternative. Because an additional trip may now happen in the outbound direction, the trip scheduling probabilities table was extended for the other discretionary tour purpose where the fourth outbound trip rows were copied for the now availabile fifth trip.
example_estimation#
ActivitySim includes the ability to re-estimate submodels using choice model estimation tools such as larch. In order to do so, ActivitySim adopts the concept of an estimation data bundle (EDB), which is a collection of the necessary data to re-estimate a submodel. See Estimation for examples that illustrate running ActivitySim in estimation mode and using larch to re-restimate submodels.
placeholder_multiple_zone#
In a multiple zone system approach, households, land use, and trips are modeled at the microzone (MAZ) level. MAZs are smaller than traditional TAZs and therefore make for a more precise system. However, when considering network level-of-service (LOS) indicators (e.g. skims), the model uses different spatial resolutions for different travel modes in order to reduce the network modeling burden and model runtimes. The typical multiple zone system setup is a TAZ zone system for auto travel, a MAZ zone system for non-motorized travel, and optionally a transit access points (TAPs) zone system for transit.
ActivitySim supports models with multiple zone systems. The three versions of multiple zone systems are one-zone, two-zone, and three-zone.
One-zone: This version is based on TM1 and supports only TAZs. All origins and destinations are represented at the TAZ level, and all skims including auto, transit, and non-motorized times and costs are also represented at the TAZ level.
Two-zone: This version is similar to many DaySim models. It uses microzones (MAZs) for origins and destinations, and TAZs for specification of auto and transit times and costs. Impedance for walk or bike all-the-way from the origin to the destination can be specified at the MAZ level for close together origins and destinations, and at the TAZ level for further origins and destinations. Users can also override transit walk access and egress times with times specified in the MAZ file by transit mode. Careful pre-calculation of the assumed transit walk access and egress time by MAZ and transit mode is required depending on the network scenario.
Three-zone: This version is based on the SANDAG generation of CT-RAMP models. Origins and destinations are represented at the MAZ level. Impedance for walk or bike all-the-way from the origin to the destination can be specified at the MAZ level for close together origins and destinations, and at the TAZ level for further origins and destinations, just like the two-zone system. TAZs are used for auto times and costs. The difference between this system and the two-zone system is that transit times and costs are represented between Transit Access Points (TAPs), which are essentially dummy zones that represent transit stops or clusters of stops. Transit skims are built between TAPs, since there are typically too many MAZs to build skims between them. Often multiple sets of TAP to TAP skims (local bus only, all modes, etc.) are created and input to the demand model for consideration. Walk access and egress times are also calculated between the MAZ and the TAP, and total transit path utilities are assembled from their respective components - from MAZ to first boarding TAP, from first boarding to final alighting TAP, and from alighting TAP to destination MAZ. This assembling is done via the Transit Virtual Path Builder (TVPB), which considers all possible combinations of nearby boarding and alighting TAPs for each origin destination MAZ pair.
Regions that have an interest in more precise transit forecasts may wish to adopt the three-zone approach, while other regions may adopt the one or two-zone approach. The microzone version requires coding households and land use at the microzone level. Typically an all-streets network is used for representation of non-motorized impedances. This requires a routable all-streets network, with centroids and connectors for microzones. If the three-zone system is adopted, procedures need to be developed to code TAPs from transit stops and populate the all-street network with TAP centroids and centroid connectors. A model with transit virtual path building takes longer to run than a traditional TAZ only model, but it provides a much richer framework for transit modeling.
Note
The two and three zone system test examples are simple test examples developed from the TM1 example. To develop the two zone system example, TM1 TAZs were labeled MAZs, each MAZ was assigned a TAZ, and MAZ to MAZ impedance files were created from the TAZ to TAZ impedances. To develop the three zone example system example, the TM1 TAZ model was further transformed so select TAZs also became TAPs and TAP to TAP skims and MAZ to TAP impedances files were created. While sufficient for initial development, these examples were insufficient for validation and performance testing of the new software. As a result, the prototype_marin example was created.
Example simple test configurations and inputs for two and three-zone system models are described below.
Examples#
To run the two zone and three zone system examples, do the following:
Activate the correct conda environment if needed
Create a local copy of the example
# simple two zone example
activitysim create -e placeholder_2_zone -d test_placeholder_2_zone
# simple three zone example
activitysim create -e placeholder_3_zone -d test_placeholder_3_zone
Change to the example directory
Run the example
# simple two zone example
activitysim run -c configs_2_zone -c configs -d data_2 -o output_2
# simple three zone example, single process and multiprocess (and makes use of settings file inheritance for running)
activitysim run -c configs_3_zone -c configs -d data_3 -o output_3 -s settings_static.yaml
activitysim run -c configs_3_zone -c configs -d data_3 -o output_3 -s settings_mp.yaml
Settings#
Additional settings for running ActivitySim with two or three zone systems are specified in the settings.yaml
and
network_los.yaml
files. The settings are:
Two Zone#
In settings.yaml
:
want_dest_choice_presampling
- enable presampling for multizone systems, which means first select a TAZ using the sampling model and then select a microzone within the TAZ based on the microzone share of TAZ size term.
In network_los.yaml
:
The additional two zone system settings and inputs are described and illustrated below. No additional utility expression files or expression revisions are required beyond the one zone approach. The MAZ data is available as zone data and the MAZ to MAZ data is available using the existing skim expressions. Users can specify mode utilities using MAZ data, MAZ to MAZ impedances, and TAZ to TAZ impedances.
zone_system
- set to 2 for two zone systemmaz
- MAZ data file, with MAZ ID, TAZ, and land use and other MAZ attributesmaz_to_maz:tables
- list of MAZ to MAZ impedance tables. These tables are read as pandas DataFrames and the columns are exposed to expressions.maz_to_maz:max_blend_distance
- in order to avoid cliff effects, the lookup of MAZ to MAZ impedance can be a blend of origin MAZ to destination MAZ impedance and origin TAZ to destination TAZ impedance up to a max distance. The blending formula is below. This requires specifying a distance TAZ skim and distance columns from the MAZ to MAZ files. The TAZ skim name and MAZ to MAZ column name need to be the same so the blending can happen on-the-fly or else a value of 0 is returned.
(MAZ to MAZ distance) * (distance / max distance) * (TAZ to TAZ distance) * (1 - (distance / max distance))
maz_to_maz:blend_distance_skim_name
- Identify the distance skim for the blending calculation if different than the blend skim.
zone_system: 2
maz: maz.csv
maz_to_maz:
tables:
- maz_to_maz_walk.csv
- maz_to_maz_bike.csv
max_blend_distance:
DIST: 5
DISTBIKE: 0
DISTWALK: 1
blend_distance_skim_name: DIST
Three Zone#
In addition to the extra two zone system settings and inputs above, the following additional settings and inputs are required for a three zone system model. Examples values are illustrated below.
In settings.yaml
:
models
- add initialize_los and initialize_tvpb to load network LOS inputs / skims and pre-compute TAP to TAP utilities for TVPB. See Initialize LOS.want_dest_choice_presampling
- enable presampling for multizone systems, which means first select a TAZ using the sampling model and then select a microzone within the TAZ based on the microzone share of TAZ size term.
models:
- initialize_landuse
- compute_accessibility
- initialize_households
# ---
- initialize_los
- initialize_tvpb
# ---
- school_location
- workplace_location
In network_los.yaml
:
zone_system
- set to 3 for three zone systemrebuild_tvpb_cache
- rebuild and overwrite existing pre-computed TAP to TAP utilities cachetrace_tvpb_cache_as_csv
- write a CSV version of TVPB cache for tracingtap_skims
- TAP to TAP skims OMX file name. The time period for the matrix must be represented at the end of the matrix name and be seperated by a double_underscore (e.g. BUS_IVT__AM indicates base skim BUS_IVT with a time period of AM).tap
- TAPs tabletap_lines
- table of transit line names served for each TAP. This file is used to trimmed the set of nearby TAP for each MAZ so only TAPs that are further away and serve new service are included in the TAP set for consideration. It is a very important file to include as it can considerably reduce runtimes.maz_to_tap
- list of MAZ to TAP access/egress impedance files by user defined mode. Examples include walk and drive. The file also includes MAZ to TAP impedances.maz_to_tap:{walk}:max_dist
- max distance from MAZ to TAP to consider TAPmaz_to_tap:{walk}:tap_line_distance_col
- MAZ to TAP data field to use for TAP lines distance filterdemographic_segments
- list of user defined demographic_segments for pre-computed TVPB impedances. Each chooser is coded with a user defined demographic segment.TVPB_SETTINGS:units
- specify the units for calculations, e.g. utility or time.TVPB_SETTINGS:path_types
- user defined set of TVPB path types to be calculated and available to the mode choice models. Examples include walk transit walk (WTW), drive transit walk (DTW), and walk transit drive (WTD).TVPB_SETTINGS:path_types:{WTW}:access
- access mode for the path typeTVPB_SETTINGS:path_types:{WTW}:egress
- egress mode for the path typeTVPB_SETTINGS:path_types:{WTW}:max_paths_across_tap_sets
- max paths to keep across all skim sets, for example, 3 TAP to TAP pairs per origin MAZ destination MAZ pairTVPB_SETTINGS:path_types:{WTW}:max_paths_per_tap_set
- max paths to keep per skim set, for example 1 per skim set - all transit submodes, local bus only, etc.
Unlike the one and two zone system approach, the three zone system approach requires additional expression files for the TVPB. The additional expression files for the TVPB are:
TVPB_SETTINGS:tap_tap_settings:SPEC
- TAP to TAP expressions, e.g. tvpb_utility_tap_tap.csvTVPB_SETTINGS:tap_tap_settings:PREPROCESSOR:SPEC
- TAP to TAP chooser preprocessor, e.g. tvpb_utility_tap_tap_annotate_choosers_preprocessor.csvTVPB_SETTINGS:maz_tap_settings:walk:SPEC
- MAZ to TAP {walk} expressions, e.g. tvpb_utility_walk_maz_tap.csvTVPB_SETTINGS:maz_tap_settings:drive:SPEC
- MAZ to TAP {drive} expressions, e.g. tvpb_utility_drive_maz_tap.csvTVPB_SETTINGS:accessibility:tap_tap_settings:SPEC
- TAP to TAP expressions for the accessibility calculator, e.g. tvpb_accessibility_tap_tap.csvTVPB_SETTINGS:accessibility:maz_tap_settings:walk:SPEC
- MAz to TAP {walk} expressions for the accessibility calculator, e.g. tvpb_accessibility_walk_maz_tap.csv
Additional settings to configure the TVPB are:
TVPB_SETTINGS:tap_tap_settings:attribute_segments:demographic_segment
- TVPB pre-computes TAP to TAP total utilities for demographic segments. These are defined using the attribute_segments keyword. In the example below, the segments are demographic_segment (household income bin), tod (time-of-day), and access_mode (drive, walk).TVPB_SETTINGS:maz_tap_settings:{walk}:CHOOSER_COLUMNS
- input impedance columns to expose for TVPB calculations.TVPB_SETTINGS:maz_tap_settings:{walk}:CONSTANTS
- constants for TVPB calculations.accessibility:...
- for the accessibility model step, the same basic set of TVPB configurations are available.
zone_system: 3
rebuild_tvpb_cache: False
trace_tvpb_cache_as_csv: False
tap_skims: tap_skims.omx
tap: tap.csv
maz_to_tap:
walk:
table: maz_to_tap_walk.csv
drive:
table: maz_to_tap_drive.csv
demographic_segments: &demographic_segments
- &low_income_segment_id 0
- &high_income_segment_id 1
TVPB_SETTINGS:
tour_mode_choice:
units: utility
path_types:
WTW:
access: walk
egress: walk
max_paths_across_tap_sets: 3
max_paths_per_tap_set: 1
DTW:
access: drive
egress: walk
max_paths_across_tap_sets: 3
max_paths_per_tap_set: 1
WTD:
access: walk
egress: drive
max_paths_across_tap_sets: 3
max_paths_per_tap_set: 1
tap_tap_settings:
SPEC: tvpb_utility_tap_tap.csv
PREPROCESSOR:
SPEC: tvpb_utility_tap_tap_annotate_choosers_preprocessor.csv
DF: df
attribute_segments:
demographic_segment: *demographic_segments
tod: *skim_time_period_labels
access_mode: ['drive', 'walk']
attributes_as_columns:
- demographic_segment
- tod
maz_tap_settings:
walk:
SPEC: tvpb_utility_walk_maz_tap.csv
CHOOSER_COLUMNS:
- walk_time
drive:
SPEC: tvpb_utility_drive_maz_tap.csv
CHOOSER_COLUMNS:
- drive_time
- DIST
CONSTANTS:
c_ivt_high_income: -0.028
...
accessibility:
units: time
path_types:
WTW:
access: walk
egress: walk
max_paths_across_tap_sets: 1
max_paths_per_tap_set: 1
tap_tap_settings:
SPEC: tvpb_accessibility_tap_tap_.csv
maz_tap_settings:
walk:
SPEC: tvpb_accessibility_walk_maz_tap.csv
CHOOSER_COLUMNS:
- walk_time
CONSTANTS:
out_of_vehicle_walk_time_weight: 1.5
out_of_vehicle_wait_time_weight: 2.0
Outputs#
Essentially the same set of outputs is created for a two or three zone system model as for a one zone system model. However, the one key additional bit of information for a three zone system model is the boarding TAP, alighting TAP, and transit skim set is added to the relevant chooser table (e.g. tours and trips) when the chosen mode is transit. Logging and tracing also work for two and three zone models, including tracing of the TVPB calculations. The Write Trip Matrices step writes both TAZ and TAP level matrices depending on the configured number of zone systems.
Presampling#
In multiple zone systems models, destination choice presampling is activated by default. Destination choice presampling first aggregates microzone size terms to the TAZ level and then runs destination choice sampling at the TAZ level using the destination choice sampling models. After sampling X number of TAZs based on impedance and size, the model selects a microzone for each TAZ based on the microzone share of TAZ size. Presampling significantly reduces runtime while producing similar results.
prototype_marin#
To finalize development and verification of the multiple zone system and transit virtual path building components, the Transportation Authority of Marin County version of MTC travel model two (TM2) work tour mode choice model was implemented. This example was also developed to test multiprocessed runtime performance. The complete runnable setup is available from the ActivitySim command line interface as prototype_3_marin_full. This example has essentially the same configuration as the simpler three zone example above.
Example#
To run prototype_marin, do the following:
Activate the correct conda environment if needed
Create a local copy of the example
# Marin TM2 work tour mode choice for the MTC region
activitysim create -e prototype_3_marin_full -d test_prototype_3_marin_full
Change to the example directory
Run the example
# Marin TM2 work tour mode choice for the MTC region
activitysim run -c configs -d data -o output -s settings_mp.yaml
For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
Settings#
Additional settings for running the Marin TM2 tour mode choice example are in the network_los.yaml
file. The
only additional notable setting is the tap_lines
setting, which identifies a table of transit line names
served for each TAP. This file is used to trimmed the set of nearby TAP for each MAZ so only TAPs that are
further away and serve new service are included in the TAP set for consideration. It is a very important
file to include as it can considerably reduce runtimes.
tap_lines: tap_lines.csv
prototype_arc#
Note
This example is in development
The prototype_arc added a Trip Scheduling Choice (Logit Choice), Trip Departure Choice (Logit Choice), and Parking Location Choice submodel. These submodel specification files are below, and are in addition to the prototype_mtc submodel Sub-Model Specification Files.
Example ARC Sub-Model Specification Files#
Model |
Specification Files |
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Example#
See example commands in example_manifest.yaml for running prototype_arc. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
prototype_semcog#
Note
This example is in development
The prototype_semcog added a Work From Home, Telecommute Frequency, Transit Pass Subsidy and Transit Pass Ownership submodel. These submodel specification files are below, and are in addition to the prototype_mtc submodel Sub-Model Specification Files. These submodels were added to prototype_semcog as extensions, which is a way for users to add submodels within their model setup as opposed to formally adding them to the activitysim package. Extension submodels are run through the models settings. However, the model must be run with the simulation.py script instead of the command line interface in order to load the extensions folder.
Example SEMCOG Sub-Model Specification Files#
Model |
Specification Files |
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Example#
See example commands in example_manifest.yaml for running prototype_semcog. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
placeholder_psrc#
Note
This example is a placeholder model used only for code development and debugging, and is not suitable for policy analysis
The placeholder_psrc is a two zone system (MAZs and TAZs) implementation of the prototype_mtc model design. It uses PSRC zones, land use, synthetic population, and network LOS (skims).
Example#
See example commands in example_manifest.yaml for running placeholder_psrc. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
placeholder_sandag#
Note
This example is in development
The placeholder_sandag is a multi-part model, containing one-, two-, and three- zone system (MAZs, TAZs, and TAPs) implementation of the prototype_mtc model design. It uses SANDAG zones, land use, synthetic population, and network LOS (skims).
Example#
See example commands in example_manifest.yaml for running placeholder_sandag. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
prototype_sandag_xborder#
Note
This example is in development
The prototype_sandag_xborder is a three zone system (MAZs, TAZs, and TAPs) that generates cross-border activities for a tour-based population of Mexican residents. In addition to the normal SANDAG zones, there are external MAZs and TAZs defined for each border crossing station (Port of Entry). Because the model is tour-based, there are no household or person-level attributes in the synthetic population. The principal difference between this and the standard 3-zone implementation is that since household do not have a default tour origin (home zones), a tour OD choice model is required to assign tour origins and destinations simultaneously.
Example#
See example commands in example_manifest.yaml for running prototype_sandag_xborder. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.
prototype_mwcog#
The prototype_mwcog is a one zone system (TAZs only).
Example#
See example commands in example_manifest.yaml for running prototype_mwcog. For optimal performance, configure multiprocessing and chunk_size based on machine hardware.