2010.04.sandag_abm_joel freedman

The SANDAG ActivityThe SANDAG Activity--Based Based Travel Travel ModelModel

Institute of Traffic Engineers Luncheon PresentationApril 1, 2010

Institute of Traffic Engineers Luncheon April 1, 2010

Trip-Based Model Overview

662

341

PiZone

Trip Productions (Pi)

182

821

AjZone

Trip Attractions (Aj)

1001882Total Aj

6611552

347271

TotalPi

21

FromZone

To ZoneTrips(Tijm)

Mode

25Transit

30Auto

Trips(Tijmr)

Route

7Route B

18Route A

Trip Generation Trip Distribution Mode ChoiceMode Choice Trip Assignment


Criticisms of Trip-Based Models

• Lack of Behavioral Fidelity– The only model based on actual decision-making theory is mode

choice (in most model systems)• Aggregation Bias

– No information on non-home-based trips– Each additional market segment (socio-economic category, trip

purpose, time period) significantly increases runtime• Lack of Policy Responsiveness

– Time-of-day shifts– Socio-economic changes– Induced travel

Institute of Traffic Engineers LuncheonApril 1, 2010

What is an Activity-Based Travel Model?

• Travel is a derived demand – it results for the need for people to engage in activities outside the home.

• Activity-based travel models attempt to replicate how people decide:– whether to travel– where to travel to– when to travel– how to travel

• Activity-based travel models are based on behavioral decision-making theory

• This makes them more suited to address policies that affect how people make travel decisions than trip-based models


Activity-Based Travel Models

• Model travel by individuals– All important socio-economic characteristics are tracked

explicitly – Micro-simulation used

• Model trips as part of tours– A series of trips beginning and ending at home or work (anchor

locations)– Primary destination, intermediate stops– No more non-home-based trips!!

• Schedule tours into available time-windows– Consistent daily activity patterns that replicate survey data

Complex Planning Issues Addressed with AB Models

• Affects of transport policies on time-use• Demographic changes & equity analysis• Demand management policies (HOV, pricing)• Changes in accessibilities• Better interface with traffic simulation models• Telecommuting• Global transportation policies & taxation• Evacuation planning



ABM: Tours and Trips

Home-Based Work Trip

Non-Home-BasedTrip

Home-BasedOther Trip

Non-Home-Based Trip

Non-Home-Based Trip

Zone 1 Zone 3

Zone 2

Zone 4

Work TourPrimary

Destination

IntermediateStop

Origin

Work-Based Tour

Origin PrimaryDestination

HH # Per # Tour # Purp OriginTAZ

Destin.TAZ

Outbound Stop1 TAZ

Return Stop1 TAZ

Mode Sub-tour

Sub-TourDestin.

1023 1 1 Work 1 3 0 2 Transit Yes 4

Data View:


Activity-Based Models: Mode Consistency

Zone 1 Zone 3

Zone 2

Zone 4

Work Tour Work-Based Tour

Bus to Work = Drive alone not available for lunch


Activity-Based Model: Micro-simulation

• A synthetic population is created that represents the actual population

• Travel is explicitly modeled for each person/household• Monte Carlo simulation is used instead of fractional

probability aggregation: Discrete choices made for each traveler

• Results are aggregated and:– Assigned to transport networks– Compiled into reports


Activity-Based Model For San Diego

• Based on the CT-RAMP (Coordinated Travel – Regional Activity-based Modeling Platform) Family of Activity-Based Travel Demand Models

• Main features:• Explicit intra-household interactions • Continuous temporal dimension (Half-hourly time periods)•Logit formulations for choice models•Sensitive to a wide range of socio-economic variables, transportation costs/accessibilities, and land-use changes•Java-based package for model implementation


Activity-Based Models In the United States

NYSan Francisco

Seattle

ColumbusDenver

Atlanta

Sacramento

Bay Area

Developed by PBDeveloped by others

Oregon

Ohio

San Diego

Lake Tahoe

CT-RAMP Family

PhoenixLos Angeles

(Atlanta model co-developed with MTC)


12 12

Joint Non-Mandatory Tours

1. Population Synthesis

2. Long-term

4. Daily

5. Tour level

6. Trip level

2.1. Usual workplace / school

4.1. Person pattern type & Joint Tour Indicator

Mandatory Non-mandatory Home

4.2.1. Frequency

4.2.2. TOD4.3.1. Frequency

4.3.2. Party

4.3.3. Participation

4.3.4. Destination

4.3.5. TOD

5.1. Tour mode 5.2. Stop frequency 5.3. Stop location

6.1. Trip mode

6.2. Auto parking

Individual Mandatory Tours

Individual Discretionary

Tours

4.5.1. Frequency

4.5.2. Destination

4.5.3. TOD

Available time budgetResidual time

6.3. Assignment

4.6.1. Frequency

At-work sub-tours

4.6.2. Destination

4.6.3. TOD

3.1. Free Parking Eligibility3. Mobility 3.3. Transponder Ownership3.2. Car ownership

Allocated Tours

4.4.1. Frequency

4.4.3. Destination

4.4.4. TOD

4.4.2. Allocation

5.4. Stop Departure

Joint(household level)


A relevant cartoon…


Activity TypesTYPE PURPOSE DESCRIPTION CLASSIFICATION ELIGIBILITY

1 Work[1] Working at regular workplace or work-related activities outside the home.

Mandatory Workers and students

2 University College + Mandatory Age 18+

3 High School Grades 9-12 Mandatory Age 14-17

4 Grade School Grades K-8 Mandatory Age 5-13

5 Escorting Pick-up/drop-off passengers (auto trips only).

Maintenance Age 16+

6 Shopping Shopping away from home. Maintenance 5+ (if joint travel, all persons)

7 Other Maintenance Personal business/services, and medical appointments.

Maintenance 5+ (if joint travel, all persons)

8 Social/Recreational Recreation, visiting friends/family.

Discretionary 5+ (if joint travel, all persons)

9 Eat Out Eating outside of home. Discretionary 5+ (if joint travel, all persons)

10 Other Discretionary Volunteer work, religious activities.

Discretionary 5+ (if joint travel, all persons)

Choice

Drive-Alone Free

Drive-Alone Pay

Shared 2 Free

Shared 2 Pay

Shared 3+ Free

Shared 3+ Pay

Walk Bike

Walk-Local Walk-BRT

Walk-Express Walk-LRT

Walk-Commuter

Rail

Drive-Alone Shared-Ride 2 Shared-Ride 3+

Non-Motorized

Walk-Transit

TransitAuto

Drive-Local Drive-BRT

Drive-Express Drive-LRT

Drive-Commuter

Rail

Drive-Transit

Modes

• Explicit toll versus non-toll choice• Explicit treatment of line-haul transit modes


Treatment of Space: TAZs and MGRAs


•About 10 MGRAs to 1 TAZ

•32k MGRAs Tot.

•All origins and destinations located at MGRA level

•Highway assignments still use TAZs

Transit Network, Stops and Access Points


•About 2,500 transit access points (stops)

• Stop-to-stop skims (TransCAD)

•All transit boardings/alights located at TAPs

Transit Paths


• On-the-fly path-building from origin MGRA, to boarding TAP, to alighting TAP, to destination MGRA


Tour Destination, Time-of-Day, Mode, Stop Location

1. Select Primary Destination

2. Select Departure/Arrival Period

4. Select Stop Location

3. Select Primary Mode


Time-Use Concept

5 23

1-Work

7-17

5-6 18-19 2-Discret

20-23

Recalculate residual time windows


Tour-Based Model Output

HID PID TID PUR MOD SB SA OTAZ DTAZ S1TAZ S2TAZ TLOR TLDS1 1 1 2 1 0 1 943 987 0 964 1 3 1 1 2 1 2 1 0 943 731 856 0 3 3 1 2 1 4 1 0 0 943 952 0 0 1 2 1 3 1 2 4 1 1 943 565 698 982 1 2

Household Data, Person Data, Tour/Trip List

Other SummariesMaps, Graphics

Trip Tables

Assignment

Work Trip Frequency Distribution:Auto Ownership 1, Income Group 1-2

Estimated vs. Observed

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

6.0%

5 8 11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59

Peak Highway Travel Time (minutes)

Freq

uenc

y ObservedEstimated

¯


What Sort of Measures/Visuals are Now Possible?

• ABM results in a complete activity diary for all SANDAG residents– A wealth of activity/travel results– Just about any custom report/query/visual is now possible

• Scenario Testing– Capacity improvements– HOV, HOT lane scenarios– Cordon Pricing– Land-use policies– New Starts– Equity Analysis

• Example Outputs


Tracing of Activities/Tours


Mode Share by Person Type

Travelers By Age

15

30

90

45

60

75

0


Persons Not At Home By TAZ and Hour


Persons By TAZ and Hour (Daytime Population)


Mean Delay Peak Period Travel


Time Spent Traveling by Income & Person Type



1. Population Synthesis

2. Long-term

4. Daily

6. Trip level (4-Step Models)

2.1. Usual workplace / school

4.1. Person pattern type

Mandatory Non-mandatory Home

4.2.1. Frequency

Individual Mandatory Tours

4.6.1a. Frequency

At-work sub-tours

3. Mobility 3.2a. Car ownership

Individual Non-Mandatory Tours4.5.1a. Frequency & Purpose

5. Tour level5.2a. Stop frequency & Purpose

Daily Trip Productions By Purpose

Trip Distribution

Mode Choice

Trip Assignment

Year 1 (2009):

Simplified activity-based travel generation models estimated, implemented, and calibrated

Model Development Schedule


• Year 2 (2010)– On-board survey data available– Tour mode choice, time-of-day choice, destination choice

• Year 3 (2011)– Trip-level models estimated, implemented – Toll transponder ownership – Employer-provided parking and parking lot choice

• Year 4 (2012)– Special market models (visitors, air passengers, special events)– PECAS (land-use model) integration– Model validation


Questions and Discussion

Joel [email protected]

2010.04.sandag_abm_joel freedman

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