TRANSIMS Research and Deployment Project

TRACC TSM StaffDr. Vadim SokolovDr. Joshua AuldDr. Kuilin ZhangMr. Michael Hope

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Model Goals

Develop an extensible software framework which can be easily adapted to solve problems which are currently difficult for FHWA to address

The effects of developing ITS infrastructure– 3CI centers– Intelligent signal systems

Interoperability: looking at the co-variant effects of historically separate models– The regional effects of a car following simulation informed dynamically by an activity

based model Enabling future models which may become of increased interest given the

appropriate framework– Regional emission calculations– Special event planning

Hold as a design criteria the needs of metropolitan planners to be able to answer a question at hand with limited information, time, and budget

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Initial Design Concept

Survey the full range of problems which are or may become of interest to transportation planners and the performance metrics which are necessary to answer these questions

Distill these ideas into a generalized transportation modeling language

Construct a framework which is transparent enough for a developer to easily write in this modeling language, but is robust enough to ensure that the level of work they must do is minimal

Illustrate how the framework may be used and how easily it may be extended by using it to build a model which can address questions related to interoperability and ITS infrastructure

Interact closely with FHWA to ensure the framework and models maintain their design criteria of extensibility, ease of use, and modeling accuracy

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Model Conceptual Framework

Land Use Synthetic Population Network

ITS Architecture

Activity Modeling

Trip Routing

Traffic Simulation

Learning

30 sec

5 min / triggers

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Writing a “Transportation Modeling Language”

The best language to look for inspiration is perhaps that of agent-based models and of machine learning.

A key focus of the agent-based modeling community has been to provide a sufficiently generalized language which may be used to solve an incredibly diverse range of problems in an inherently modular way.

It is not necessary for our language to be as general as that of traditional agent-based models, we can make a number of simplifying assumptions which are specific to transportation while still preserving the modularity necessary to address a diverse set of planning problems.

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Conceptual Framework Elements

Transportation Agent Building Blocks

Transportation Environment Building Blocks

Task Scheduling Engine and Execution Cells

Global System State Coherency based on ACID Principles

Developer APIs, Utility Functions, and Data Structures

Clear and Accessible Documentation

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Putting the Framework into Action

The initial application of the framework is to develop a model which may be used to test “what if” scenarios related to:– The efficacy of implementing new ITS infrastructure– Traditional highway capacity and long range planning– The effects of activity choice on higher resolution model components

The following transportation planning elements will be modeled in a fully integrated fashion:– Intelligent Transportation System Behavior– Activity Choice– Mode Choice– Parcel-Level Destination Choice– Departure Time Choice– Route Choice– En Route Path Choice– High Resolution Traffic Simulation: Car Following, Lane Changing– Low Resolution Traffic Simulation: Queue-based Model

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Putting the Framework into Action cont’d

The model takes as input a supply network, a base population, ITS infrastructure, and land use information

The model executes continuously (does not iterate)

Agents learn over time; these “lessons” can be saved and re-used in future models

The user specifies a “virtual observer” to watch and output parameters of interest

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Anticipated Extensions

A crucial design criteria of the framework is that the above model may be easily extended or re-molded to investigate these other topics of interest to FHWA.

Emissions: evaluate the change in emissions following a policy change

Transit: evaluate the level of service of a new high speed rail system

Novel ITS Concepts: observe the regional effects of an Intellidrive system

Research Community: drop in and test alternative models for car following, route choice, mode choice, etc…

Freight: identify the regional logistical impacts of a new freight system

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Anticipated Extensions cont’d

Safety: test alternative highway and intersection geometries to improve driver safety

Parking: test alternative parking system layouts in a municipality, determine the effects of allowing on-street parking

Energy: determine the impact of increased hybrid vehicle market penetration

Pedestrians/Bicyclists: examine the effects of pedestrian behavior on a transportation system, test new pedestrian walkways or bicycle lanes

Weather: test models for how weather affects a transportation system

Social Networks: examine the effects a social network can have on activity choice and further on a transportation system as a whole