Guy Rousseau, Modeling Manager, Atlanta Regional Guy Rousseau, Modeling Manager, Atlanta Regional CommissionCommission

Atlanta Travel Forecasting Methods:

Traditional Trip-Based

&

Activity-Based Model

AMPO Travel Modeling Work Group, Nov. 4, 2010

ARC Model Applications: Using Radar Graphs to Visualize Performance Measures

1Coordinated Travel-Regional Activity-Based Modeling Platform

ARC Activity-Based Modeling System

• Based on the CT-RAMP1 family of ABMs developed in New York, NY, Columbus OH (MORPC) and others

- Explicit intra-household interactions - Continuous temporal dimension (Hourly time periods)- Integration of location, time-of-day, and mode choice models- Java-based package for AB model implementation

• Implemented with the existing Cube-based networks, GUI and ancillary models (external model, truck model, assignments, etc)

• Households: 1.7 million in 2005, 2.7 million in 2030

• Model development parallel effort with MTC

The ARC CT-RAMP Cluster4 8-processor dual-core Dell servers with 32 GB RAM each

ARC Activtiy-Based Model

Hardware and Software Setup

• Three Windows Server 2003 64bit Machines:• Two Dual Quad Core Intel

Xeon X570 2.93 GHz Processors 16 threads

• 32 GB of RAM• Cube Voyager + 8 seat

Cube Cluster license

• Total cost ~ $30,000 in 2009

ARC Activity-Based Model

Hardware and Software Setup

• 64 bit OS for large memory addresses• 64 bit Java for CT-RAMP• 32 bit Java to integrate with Cube’s native matrix I/O DLL• Cube Base for the GUI• Cube Voyager + Cluster for running

the model, assignment, etc• Java CT-RAMP software• 64 bit R for reporting/visualization

ARC’s Activity-Based Model• Provides results similar to 4-step trip based

model• Ok, so then why bother with an ABM?• Because ARC’s ABM provides additional details,

more info about travel patterns & market segments

• ABM allows to answer questions the 4-step model is not capable to provide

• For internal use only, not for official purposes, hence dual/parallel track of models

Synthesized Population: Person Age Share

Trip-Based Model Mode Share Compared to ABM Mode Share

Line Boardings: Trip Based Model Versus ABM

AM SOV Free:Trip Length Frequency Distributions

VMT by Time Period

ARC’s ABM Year 2005 Volume/Count Scatterplot

Line Boardings (Routes > 10,000 Boards)

Station Boardings By Number of Boards

External Model ResultsTBM ABM

2030HOV2HOT 2030HOV2HOTPassenger ODRelation Trips TripsWork IE 390,787 388,150 Non-Work IE 510,557 507,103 Passenger Cars EE 80,219 80,563 TruckTrucks II 2,518,171 2,518,837 Trucks IE 234,545 233,478 Trucks EE 25,573 40,793

What Sort of Performance Measures & Visuals are Possible with an Activity-Based Model?

ABM results in a complete activity diary for all ARC residents

•A wealth of activity/travel results

•Just about any custom report/query/visual is now possible

•Performance Measures also available by Age, Gender & Household Types

Mean Delay, Peak Period Travel

Travelers By Age

Persons Not At Home By TAZ and Hour

Persons By TAZ and Hour

Conclusions

• Overall, the ARC ABM model appears to be displaying appropriate sensitivities when compared to the base year results and the existing trip based model runs.

• Compared with the trip based model run, the ABM required increased prices in the peak periods in order to provide 1600 vphpl performance given the significant amount of toll eligible demand that could use the facilities

• VMT results by time-of-day suggest that the addition of a trip time-of-day departure choice model would help reduce the over predicted night period demand

Potential Improvements

• The population synthesizer works at the household level. Adding more explicit functionality for person level information and controls would be useful.

• The ABM does not have a model to calculate the departure hour for each trip within the tour time window. Adding a model, or simply a distribution of probabilities by tour purpose and hour, would be an improvement

Questions / Comments

Guy Rousseau (404 463-3274) grousseau@atlantaregional.com

Atlanta Regional Commission

40 Courtland Street, NE

Atlanta, Georgia 30303

www.atlantaregional.com

Acknowledgements: PBS&J, AECOM, Parsons Brinckerhoff, John Bowman, Mark Bradley, Bill Allen