A sophisticated scenario control system is used to simulate traffic within the virtual environment. The system uses a microscopic traffic simulation engine augmented with high-level coordinators that can orchestrate specific events authored by the experimenter, including weather conditions, vehicle interactions, and mechanical failures. Individual driver behavior models control scenario vehicles; their behavior has been calibrated to match empirically obtained traffic data.

A rich set of coordinators allows the management of predefined events that can reliably occur during the simulation. Coordinators can trigger events based on geometric and relative locations of specific vehicles with respect to each other or the participant, mathematical expressions involving data from the simulation, and time. Coordinators also trigger several types of actions within the virtual world, including the creation or deletion of scenario elements, commands to control vehicle behavior, triggering of specific audio cues, and controlling the state of traffic lights, as well as inserting markers into the data being collected, performing embedded data reduction, and pre-positioning the motion base.

The Interactive Scenario Authoring Tool (ISAT™) allows users to graphically author complex scenarios. The ISAT runs on typical desktop and laptop computers. Scenarios built using the ISAT can then be executed on NADS simulators or any other simulator that supports the NADS scenario (SCN) specification format.

The ISAT in edit mode
(Click on the image for a larger version)
The ISAT in playback mode
(Click on the image for a larger version)

 

Areas of research under this effort include:

- Building a library of road networks, with associated traffic lights and signs, following AASHTO guidelines and engineering standards

- Development of the Logical Road Information (LRI) format for specifying road networks, including complex road networks that mimic American and European locations

- Development of the Correlated Virtual Environment Database (CVED), featuring a rich set of real-time queries that provide information about the road network and any object in it

- Development of behavior modeling software that enables autonomous or externally modifiable and controllable behaviors, including lange changes and intersection navigation

- Utilization of a set of coordinators allowing experimenters fine control over the events in the scenario

- Development of a mature version of a graphical scenario authoring tool called the Interactive Scenario Authoring Tool (ISAT)


 

 

 

 

 



Selected references:
Design of simulator scenarios to study the effectiveness of
electronic stability control systems,
Ahmad, O., Proceedings of the 85th Annual Meeting of the TRB, 2005

Driving simulation scenario definition based on performance measures,
Ahmad, O., Driving Simulation Conference-North America, 2005

Issues related to the commonality and comparability of driving simulation scenarios, Ahmad, O., IMAGE Conference, 2005

Scenario definition and control for the National Advanced Driving Simulator,
Papelis, Y.E., Ahmad, O., Schikore, M.C.,
International Conference on the Enhanced Safety of Vehicles (ESV), 2001

HCSM: A framework for behavior and scenario control in virtual environments,
Cremer, J., Kearney, J., Papelis, Y.E., ACM Transactions on Modeling and Computer Simulation 5, 1995

Developing scenarios to determine effects of driver performance: techniques for authoring and lessons learned, Papelis, Y., Ahmad, O., Watson, G.,
Driving Simulation Conference-North America, 2003

Driving Simulation scenario definition based on performance measures,
Papelis, Y.E., Ahmad, O., Watson, G.,
Driving Simulation Conference-North America, 2005

Design of simulator scenarios to study the effectiveness of electronic
stablity control systems, Watson, G., Papelis, Y.E., Ahmad, O., Proceedings
of the 85th Annual Meeting of the Transportation Research Board, 2006