Exploratory Advanced Research . . . Next Generation Transportation Solutions

Modeling Complex Behaviors and Interactions 

New Methods to Assist Decisionmaking and System Operations

New Methods

The VASTO modeling system incorporates 

innovative ideas in the area of agent-based 

modeling, such as the Belief-Desire-Intention 

model, and is able to model four categories of 

agents: commuters, commercial operators, traffic 

management agencies, and policy makers. This 

enables modeling of both users and the managers 

of a transportation system. The different agents 

are then able to interact with other agents in any 

category and these interactions and decisions can 

be played out in various simulations. The end 

results can also be integrated with geographic 

information system data for enhanced 

visualization.

Incorporating the influence and interaction of 

different agents in a simulation sets VASTO apart 

from traditional analysis tools and enables a longterm evolutionary outlook for a model with these 

factors taken into account. The system integrates 

robust decisionmaking behavior rules from 

models based on decades of research in decision 

science, adopts state-of-the-art parallel 

computational techniques for optimal 

performance, and utilizes computational geometry 

techniques to present data in a visual and 

understandable manner.

Multimodal Challenges 

A multimodal transportation system can be 

viewed as a hierarchy, ranging from individual 

travelers at the lower level to traffic management 

agencies and policy decisionmakers at the top. 

Interaction models that can take into account the 

behavioral aspects of both agents making daily 

commutes and commercial vehicle operators are 

recognized as the weakest link in existing 

transportation models and simulation tools. A key 

focus area for this research team is measuring the 

interaction rules among heterogeneous agents at 

a higher level, in which an agency’s management 

strategy or advocated policy would directly 

impact the travel behaviors of both commuting 

and commercial agents. The challenge for this 

study is to ensure that the ABMS system is 

sensitive to new policy or traffic management 

strategies.

The Exploratory Advanced Research Program Fact Sheet

Modeling Capability

Existing traffic simulation models and travel 

demand forecasting methods are not always 

able to provide adequate capability when faced 

with the complexity of today’s transportation 

systems. For example, these models are often 

designed to match limited sample survey data 

and are incapable of interpreting the ongoing 

effect of new policies or events. Additionally, 

most current simulation models incorporate 

only commuters, not taking into account 

transportation agencies and policy makers—

both critical components of the entire system. 

“We aim to utilize computational and 

algorithmic advances in other areas as an 

opportunity to improve our existing analysis 

capabilities,” explains David Yang at FHWA. He 

continues, “With this study, we plan to develop 

a theoretically sound, behaviorally robust, and 

computationally efficient transportation analysis 

modeling system that seamlessly integrates the 

concepts of agent-based modeling with existing 

and emerging simulation tools.”

Anew Federal Highway Administration 

(FHWA) Exploratory Advanced Research 

(EAR) Program study, “VASTO – Evolutionary 

Agent System for Transportation Outlook,” aims 

to understand the interactions between 

travelers, vehicles, traffic management agencies 

and transportation policies using agent-based 

modeling and simulation (ABMS). The study, 

conducted in partnership with the University of 

Arizona and George Mason University, will aid 

decisionmaking on transportation investments 

and contribute to effective management 

strategies; leading to a safer, more efficient 

transportation system.
Assisting Decisionmaking

The ultimate goal of this study is to deliver a set of 

comprehensive modeling tools, consisting of a 

database, multimodal transportation simulation 

platform, multiagent system simulation platform, 

and efficient data analysis and visualization 

capability. This will be driven by effective 

computational geometry, allowing 

a vast amount of raw simulation 

data to be processed, stored, 

analyzed, and displayed. The 

human-machine interface is also 

designed to aid the user in 

achieving the desired model runs, 

formulate questions to be asked, 

and select answers to be 

displayed. 

The research is expected to lead 

to the production of a 

revolutionary system and set of 

tools for a multiagent system 

modeling framework. It is 

anticipated that transportation 

agencies around the country 

would greatly benefit from 

successful deployment of this 

technology by enabling them to 

measure the impact of a strategy 

or policy, such as a higher fuel tax 

or toll facility, on travel behavior. 

Moving Modeling Forward

This VASTO study is expected to ultimately result 

in several innovative ideas. It will supply 

fundamental knowledge on how ABMS can be 

useful for transportation system analysis, it will 

provide open-source computer programs for 

other researchers to utilize, and it will attract 

forward looking practitioners and agencies to try 

the system to gain insight into test cases. It is 

anticipated that the modeling system will become 

a catalyst to jump-start more research and 

potentially revolutionize the future of 

transportation modeling and analysis. 

Yang explains, “This study will explore and 

demonstrate the capability of agent-based 

modeling to capture the actions and interactions 

of various travelers, transportation agencies, and 

policies.” He continues, “Results from this work 

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research 

(EAR) Program focuses on long-term, 

high-risk research with a high payoff 

potential. The program addresses 

underlying gaps faced by applied 

highway research programs, anticipates 

emerging issues with national implications, 

and reflects broad transportation industry 

goals and objectives. 

To learn more about the EAR Program, 

visit the Exploratory Advanced 

Research Web site at www.fhwa.dot.gov/

advancedresearch. The site features 

information on research solicitations, 

updates on ongoing research, links to 

published materials, summaries of past 

EAR Program events, and details on 

upcoming events. For more information, 

contact David Kuehn at FHWA, 202-493-

3414 (david.kuehn@dot.gov), or contact 

Terry Halkyard at FHWA, 202-493-3467 

(terry.halkyard@dot.gov).

Modeling Complex Behaviors and Interactions 

New Methods to Assist Decisionmaking and System Operations

Publication No. 

FHWA-HRT-12-069

HRTM-30/10-12(1M)E

will advance our ability to realistically mimic 

various behaviors in a computer-simulated 

transportation network and examine their 

impacts.”

Learn More

For more information on this EAR Program 

project, contact David Yang, Ph.D., FHWA Office 

of Safety Research and Development, at 202-

493-3284 (email: david.yang@dot.gov). 

Photo credit, page 1: 

© iStockphoto/

Lya_Cattel

Photo credit, page 2: 

Yi-Chang Chiu, Ph.D.

VASTO system architecture