00619147

Component

http://onlinepubs.trb.org...trr/1991/1306/1306-005.pdf

https://scholar.google.co...kker&publication_year=1991

Traffic simulations are widely used for long- and medium-term forecasting of traffic. Now-a-days, with the growing problem of queues during rush hours, the demand arises for dynamic traffic management and, therefore, short-term forecasting. Apart from the need for new, adapted dynamic assignment models the second important part in this new development is the required computational power. Most commercially available computers are unable to produce an accurate forecasting for the next 5 to 30 min. within the desired time and budget. Analysis of existing assignment models and their most time consuming part--shortest path finding--has shown that the main structure of the models can be parallelized. The use of parallelism thus seems apparent. Several general purpose parallel computers, such as N-cubes, are commercially available. However, apart from being more expensive they loose a large part of their expected performance by the amount of necessary interprocessor communications. Additionally, the programming of such computers has turned out to be more difficult than expected. A simple linear array of typically 16 processors, the so called Linear Processor Array (LPA) is proposed. This one-dimensional parallel computer with high-speed buffered interconnections between each pair of neighboring processor boards, parallel accessible by both a control board and a general-purpose host computer, forms a transparent concept for the programmer. The optimally configured boards together with the high speed intercommunication allow a cost/performance improvement factor of 100 compared with a minisupercomputer like the Convex C1. LPA should be a powerful tool for future developments of on-line traffic control, route guidance, ramp metering, among other things.

This paper appears in Transportation Research Record No. 1306, In-Vehicle Information Systems: Modeling Traffic Networks and Behavioral Considerations 1991. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01407139

p. 40-48

1991

Transportation Research Record

0309051142

Figures (2) ; References (16) ; Tables (3)

Parallel processing; Time duration; Traffic forecasting; Traffic simulation

Short term

Highways; Planning and Forecasting; I72: Traffic and Transport Planning

TRIS, TRB, ATRI

Feb 29 1992 12:00AM

• COMPARATIVE ASSESSMENT OF ORIGIN-BASED AND EN ROUTE REAL-TIME INFORMATION UNDER ALTERNATIVE USER BEHAVIOR RULES
• DYNAMIC NETWORK TRAFFIC ASSIGNMENT AND ROUTE GUIDANCE VIA FEEDBACK REGULATION
• EFFECTIVENESS OF INFORMATION SYSTEMS IN NETWORKS WITH AND WITHOUT CONGESTION
• EVALUATION OF CONTROL STRATEGIES THROUGH A DOUBLY DYNAMIC ASSIGNMENT MODEL
• LABORATORY ASSESSMENT OF DRIVER ROUTE DIVERSION IN RESPONSE TO IN-VEHICLE NAVIGATION AND MOTORIST INFORMATION SYSTEMS
• MULTIPLE USER CLASS ASSIGNMENT MODEL FOR ROUTE GUIDANCE
• NEW DYNAMIC MODEL TO EVALUATE THE PERFORMANCE OF URBAN TRAFFIC CONTROL SYSTEMS AND ROUTE GUIDANCE STRATEGIES
• USING AN INTERACTIVE ROUTE-CHOICE SIMULATOR TO INVESTIGATE DRIVERS' COMPLIANCE WITH ROUTE GUIDANCE ADVICE