01349723

Component

http://www.trb.org/Publications/Blurbs/165625.aspx

Imagery collected from airborne platforms has long been used to document the evolution of traffic congestion over time and across extended areas. The authors have documented such published research dating all the way back to 1927, and these activities continued in various periods of activity up through the late 1980s. Beginning in the late 1990s, many important ideas, new and old, on the use of airborne imagery for traffic analysis were investigated and tested in the field by a number of research teams around the world. Through detailed image processing techniques, this imagery can be used to automatically determine traffic flow measures. Prototype software tools have been developed to automatically estimate queue lengths at intersections, to estimate vehicle speeds, and to estimate vehicle flows and densities. Similar research has integrated traffic flow data from airborne imagery into formal data collection programs, where the data from the imagery is fused with ground detector data to enhance the estimates and forecasts of traffic flows. Some of these research teams have also “architectured” approaches to automatically, in real-time, georeference images from remote cameras for managing traffic. This is done by integrating the imagery with information on the height, location, and orientation of the camera. Using these camera data, in combination with a geographic representation (latitude–longitude) of the area to be studied, lead to an explicit way to georeference the road and vehicle locations. Absolute values of vehicle positions, speeds, accelerations, decelerations, and lane changes can be determined. There have been a wide variety of experiments in this area; these tests have extracted individual vehicle trajectories from digital video imagery. Uses of the obtained airborne traffic data are many: (a) off-line analyses can be used for transportation planning purposes, (b) online, real-time analyses can be used for traffic management, especially in areas where ground sensors are not available and for large-scale incidents, and (c) one can develop data sets of vehicle trajectories for use in the calibration–validation of micro-, meso-, and macroscopic traffic flow models.

01349716

English

pp 121-132

2011-6

Transportation Research Circular

Greenshields 75 Symposium

Web

Figures (5) ; References

Calibration; Digital video; Highway traffic control; Image processing; Macroscopic traffic flow; Mesoscopic traffic flow; Microscopic traffic flow; Traffic flow; Traffic flow theory; Traffic forecasting; Traffic models; Validation; Vehicle trajectories

Aerial imagery; Airborne traffic surveillance; Data integration; Georeferencing

Highways; Operations and Traffic Management; I71: Traffic Theory

TRIS, TRB

Aug 12 2011 3:19PM

• A Macroscopic Fundamental Diagram of Urban Traffic: Recent Findings
• A Simple and Pragmatic Representation of Traffic Flow
• A Stochastic Macroscopic Modeling Framework to Interpret the Fundamental Diagram
• Analysis of LWR Model with Fundamental Diagram Subject to Uncertainty
• Bird’s Eye Perspective on Traffic Flow: New Insights from Observing Traffic from a Helicopter
• Calibrating Speed–Density Functions for Mesoscopic Traffic Simulation
• Calibration of Steady-State Car-Following Models Using Macroscopic Loop Detector Data
• Effect of Lane-Change Maneuvers on a Simplified Car-Following Theory
• Empirical Relation Between Stochastic Capacities and Capacities Obtained from the Speed-Flow Diagram
• From Inductance Loops to Vehicle Trajectories
• Fundamental Diagram for Signalized Arterials: An Empirical Analysis Using High-Resolution Traffic Data
• Fundamental Diagram on Urban Roads: Myth or Truth?
• Greenshields’ Legacy: Highway Traffic
• Greenshields’ Legacy: Urban Streets
• Influence of Various Restrictions on Speed-Flow Models
• Lane-Change Maneuver Detection with Differential Global Positioning System Data from Probe Vehicle
• Measuring Traffic Flow Using Real-Time Data
• Modern Approaches to Basic Traffic Modeling: Three-Phase Traffic Theory
• Quality of Service Beyond the Traditional Fundamental Diagram
• Strategies to Improve Dissipation into Destination Networks Using Macroscopic Network Flow Models
• Traffic Flow Prospectives: From Fundamental Diagram to Energy Balance
• Traffic Flow Theory Historical Research Perspectives
• Treiterer’s Legacy: Traffic Flow Measurements and Characteristics