Finding Near-Optimal Locations for Variable Message Signs for Real-Time Network Traffic Management

2003 ◽  
Vol 1856 (1) ◽  
pp. 34-53 ◽  
Author(s):  
Nathan Huynh ◽  
Yi-Chang Chiu ◽  
Hani S. Mahmassani
Keyword(s):  
Real Time ◽  
Network Traffic ◽  
Traffic Management ◽  
Dynamic Traffic Assignment ◽  
A Priori ◽  
Optimal Solution ◽  
Solution Procedure ◽  
Variable Message Signs ◽  
Message Signs ◽  
Short Time

This study addressed the problem of finding the best locations for portable variable message signs to divert traffic to alternative paths when an incident occurs so that impact on the network is minimized. The study proposed and evaluated a solution procedure for finding such locations in the context of real-time network traffic management. In this context, it was essential that the procedure find the solution to the formulated mathematical program in a relatively short time. The procedure relied on a heuristic to guide the search and a simulation-based dynamic traffic assignment program to evaluate the solution. The proposed heuristic combined principles of greedy and drop heuristics. To evaluate the proposed solution procedure, four sets of experiments were conducted on the Fort Worth, Texas, network. The results from the proposed solution procedure are compared with those obtained by other methods—( a) an a priori solution to a stochastic programming formulation, and ( b) the optimal solution with an exact (but slow to execute) procedure. It is found that the solutions obtained from the proposed solution procedure consistently outperform the a priori solutions and that they are consistently within 15% of the optimal solutions.

Link Flow Evaluation Using Loop Detector Data: Traveler Response to Variable-Message Signs

1996 ◽  
Vol 1550 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Youngbin Yim ◽  
Jean-Luc Ygnace
Keyword(s):  
Real Time ◽  
Traffic Management ◽  
Preliminary Investigation ◽  
Traffic Information ◽  
Mean Flow ◽  
Variable Message Signs ◽  
Real Time Traffic ◽  
Operational Test ◽  
Paris Region ◽  
Message Signs

Système d'Information Routière Intelligible aux Usagers (SIRIUS) is the largest urban field operational test of the advanced traveler information and automated traffic management system in Europe. With variable-message signs, SIRIUS has been in operation in the Paris region for 3 years. A preliminary investigation of the effectiveness of the SIRIUS system in traffic management is presented. The extent to which drivers respond to real-time traffic information and the consequential changes in link flow under SIRIUS is also presented. Time-series traffic data were analyzed to measure changes in mean flow rates at a selected link. It was found that variable-message signs influence drivers to choose less congested routes when drivers are provided with real-time traffic information, and that a driver's decision to divert is closely associated with the information pertaining to the level of congestion. In the Paris region, drivers received information on the length of the queue at the time of this study. As congestion becomes heavier, drivers are more likely to respond to variable-message signs. According to the data analysis, a queue length of 3 km seems to be a threshold at which a significant number of drivers choose to use an alternative route.

MISSION-ADAPTABLE ROUTE PLANNING IN UNCERTAIN AND ADVERSARIAL ENVIRONMENT

2006 ◽  
Vol 15 (05) ◽  
pp. 803-821 ◽  
Author(s):  
PING YAN ◽  
MINGYUE DING ◽  
CHANGWEN ZHENG
Keyword(s):  
Real Time ◽  
A Priori ◽  
Route Planning ◽  
Optimal Solution ◽  
Dijkstra Algorithm ◽  
Solution Quality ◽  
Model Complex ◽  
Local Methods ◽  
Domain Specific Knowledge ◽  
Planning Algorithm

In this paper, the route-planning problems of Unmanned Aerial Vehicle (UAV) in uncertain and adversarial environment are addressed, including not only single-mission route planning in known a priori environment, but also the route replanning in partially known and mission-changeable environments. A mission-adaptable hybrid route-planning algorithm based on flight roadmap is proposed, which combines existing global and local methods (Dijkstra algorithm, SAS and D*) into a two-level framework. The environment information and constraints for UAV are integrated into the procedure of building flight roadmap and searching for routes. The route-planning algorithm utilizes domain-specific knowledge and operates in real time with near-optimal solution quality, which is important to uncertain and adversarial environment. Other planners do not provide all of the functionality, namely real-time planning and replanning, near-optimal solution quality, and the ability to model complex 3D constraints.

Content of Variable Message Signs and On-Line Driver Behavior

2000 ◽  
Vol 1725 (1) ◽  
pp. 102-108 ◽  
Author(s):  
Srinivas Peeta ◽  
Jorge L. Ramos ◽  
Raghubhushan Pasupathy
Keyword(s):  
Network Traffic ◽  
Traffic Control ◽  
Stated Preference ◽  
Control Variable ◽  
Relevant Information ◽  
Spatial Knowledge ◽  
Variable Message Signs ◽  
Driver Response ◽  
Traffic Conditions ◽  
Message Signs

Variable message signs (VMS) are programmable traffic control devices that convey nonpersonalized real-time information on network traffic conditions to drivers encountering them. Especially useful under incidents, VMS aim to influence driver routing decisions to enhance network performance. This study investigates the effect of different message contents on driver response under VMS. Presumably, if the message content is a significant factor in driver response, the traffic controller can use it as a control variable to influence network traffic conditions positively without compromising the integrity of information. This issue is addressed through an on-site stated preference user survey. Logit models are developed for drivers’ diversion decisions. The analysis suggests that content in terms of the level of detail of relevant information significantly affects drivers’ willingness to divert. Other significant factors include socio-economic characteristics, network spatial knowledge, and confidence in the displayed information. Results also indicate differences in the response attitudes of semitrailer truck drivers compared to other travelers. They provide substantive insights for the design and operation of VMS-based information systems.

Routing Profile Updating Strategies for Online Hybrid Dynamic Traffic Assignment Operation

2003 ◽  
Vol 1857 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Yi-Chang Chiu ◽  
Hani S. Mahmassani
Keyword(s):  
Real Time ◽  
System Performance ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
A Priori ◽  
Traffic Network ◽  
Route Guidance ◽  
Dynamic Traffic ◽  
Simulation Experiments ◽  
Principal Mechanism

An online routing profile updating automaton (ORPUA) approach is introduced as a principal mechanism for operating an online hybrid dynamic traffic assignment (DTA) system for real-time route guidance in a traffic network. The hybrid DTA approach integrates the centralized and the decentralized DTA frameworks by partitioning the set of guided users into two classes according to an initial routing profile (IRP). One class receives the centralized DTA guidance, while the other follows the decentralized DTA routing. ORPUA takes the a priori IRP and updates the guidance supplied to vehicles in a real-time fashion according to the unfolding network conditions and relative performance of the two classes of users. It does not anticipate the future network conditions; instead, it reacts to them and optimizes the overall system performance by improving the performance of the underperforming class of vehicles. Simulation experiments illustrate ORPUA’s potential in maintaining desirable system performance and robustness in most of the demand-supply scenarios considered.

Four-Dimensional Interactive Visualization System for Transportation Management and Traveler Information

2005 ◽  
Vol 1937 (1) ◽  
pp. 152-158 ◽  
Author(s):  
Michael L. Pack ◽  
Phillip Weisberg ◽  
Sujal Bista
Keyword(s):  
Real Time ◽  
Traffic Control ◽  
Traffic Management ◽  
Prototype System ◽  
Traveler Information ◽  
Visualization System ◽  
Dynamic Message Signs ◽  
Traffic Sensors ◽  
Real Time Traffic ◽  
Message Signs

This research developed a system for visualizing four-dimensional (4-D), real-time transportation data for the major road networks of Washington, D.C., Northern Virginia, and the entire state of Maryland. The effort employed a combination of OpenGL and other modeling techniques to develop a scalable, highly interactive 4-D model using available geographic information system (GIS) and transportation infrastructure data in conjunction with real-time traffic management center data. The prototype system interacts with real-time traffic databases to show animations of real-time traffic data (volume and speed) along with incident data (accident locations, lane closures, responding agencies, etc.). A user can “fly” or “drive” through the region to inspect conditions at an infinite number of angles and distances. The program also allows users to monitor the status of and interact with traffic control devices such as dynamic message signs, closed-circuit television feeds, and traffic sensors and even view the location of emergency response vehicles equipped with Global Positioning System transceivers. Because the system uses standard GIS data and relatively standard transportation databases to derive traffic measures, it can be scaled to incorporate other states and agencies.

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