What are Dynamic Traffic Management Systems?

A dynamic traffic management system uses simulation models combined with real-time traffic and origin-destination information to predict the effects of various management strategies, thus allowing more effective management and providing better traffic information than is currently possible. Route choice, travel time, and departure time data are collected from several sources of real-time information, such as loop detectors, roadside sensors, and GPS-equipped vehicle probes. This travel information is then used, along with simulation models, to predict network flow patterns and travel times given various combinations of management strategies such as incident management, ramp metering, signal control, and traveler information. On the basis of these predictions, optimal strategies are selected and travel time predictions and route recommendations are made available to travelers.

Key Results

These systems are still under development. They require more traffic data than is generally available, particularly information on origins and destinations. GPS-equipped vehicles promise to provide the origin-destination data needed for such systems.

When fully operational, traffic management systems can potentially provide more accurate traveler information, thereby optimizing road user route choice, and reduce congestion and delays by applying the most effective management strategies.

Where are Dynamic Traffic Management Systems Being Developed?

In 1998, two traffic estimation and prediction system prototypes, DynaMIT and DYNASMART-X, were developed by MIT and the University of Texas at Austin respectively. These prototypes were instigated under Phase 1 of the Dynamic Traffic Assignment (DTA) project. Upon completion of laboratory evaluations, these traffic estimation and prediction systems will be field-tested in Knoxville, Tennessee and at the University of California, Irvine. The prototype(s) with potential for real time operations will be refined and made available for initial deployments in Phase 2, which is projected to begin in 2002-2003. For more detailed information on these projects see Dynamic Traffic Assignment.

DYNASMART-X: A Traffic Estimation and Prediction System Case Study

DYNASMART-X is sponsored by Federal Highway Administration (FHWA) with Oak Ridge National Laboratory (ORNL) acting as the project manager and is being developed at the University of Texas at Austin. DYNASMART-X is a real-time computer system for traffic estimation and prediction that supports both transportation management systems and advanced traveler information system (ATIS). DYNASMART-X interacts continuously with multiple sources of real-time information, such as loop detectors, roadside sensors, and vehicle probes. It integrates this information with its own model-based representation of the network traffic condition.

DYNASMART can provide:

• Reliable estimates of network traffic conditions
• Predictions of network flow patterns and travel times in response to various contemplated traffic control measures and information dissemination strategies.
• Routing information to guide trip-makers in their travel

DYNAMSMART modeling features include:

• A simulation-based dynamic traffic assignment system with micro-simulation of individual user decisions (i.e. made in response to information), as well as a mesoscopic traffic flow simulation approach.
• Recognizes multiple user classes in terms of 1) operational performance (e.g. trucks, busses, etc) 2) information availability and type 3) user behavior rules and response to information.
• Fully integrates transportation management systems and advanced traveler information systems (ATIS) under different operational scenarios and deployment levels.
• Provides guidance information and control actions that are robust under various operational conditions.

DYNASMART applications include:

• Off-line design and on-line generation and evaluation of operational strategies, including real-time signal control strategies, coordination schemes along arterials, and path-based coordination schemes.
• Provision of network status information to private and public advanced traveler information system service providers.
• Determination of optimal congestion pricing schemes that vary with location, time, and prevailing network state.

DYNASMART-X is still being tested and evaluated for performance and accuracy of information.

DynaMIT: A Traffic Estimation and Prediction System Case Study

DynaMIT is sponsored by Federal Highway Administration (FHWA) with Oak Ridge National Laboratory (ORNL) acting as the project manager and is being developed at the Massachusetts Institute of Technology (MIT). DynaMIT is a real-time computer system for traffic estimation, prediction, and generation of traveler information and route guidance. It supports the operation of traffic management systems and advanced traveler information systems (ATIS) at traffic management centers (TMC).

• Real-time estimation of network conditions.
• Rolling-horizon predictions of network conditions in response to traffic control measures and information dissemination strategies.
• Traffic information and route guidance for roadway users.

DynaMIT features include:

• Demand simulation using a micro-simulator which generates individual travelers and simulates their choices regarding whether or not to travel, departure time, mode, and route in response to advanced traveler information.
• Simulation of different vehicle types and driver behaviors.
• Distinguishes between informed and uninformed drivers.
• Iterates through 1) the predicted network state 2) driver responses to information 3) the resulting network state, toward the generation of consistent information strategy.

DynaMIT applications include:

• Generation of unbiased and consistent information to drivers
• Efficient operation of Variable Message Signs (VMS)
• Off-line evaluation of real-time incident management strategies
• Real-time incident management and control

DynaMIT is still undergoing field-tests and evaluation.

Learn More

Using GPS Data to Understand Variations in Path Choice (University of Wisconsin Report)

GPS-GIS Integrated Systems for Transportation Engineering (from www.GISdevelopment.net)

Dynamic Traffic Assignment (this link contains descriptions of DynaMIT and DYNASMART-X)

Author: Lauren Smith
            Last Update: 04/01/02