00494978

Component

http://onlinepubs.trb.org...trr/1989/1232/1232-003.pdf

https://scholar.google.co...hyar&publication_year=1989

In response to growing freeway congestion problems in the Seattle area, the Washington State Department of Transportation (WSDOT) initiated a ramp-control program in 1981 as part of a region-wide transportation system management effort. The ramp-metering system is a computer-based, distributed intelligence system that consists of field-located microprocessors and a centralized computer system. It is an integrated, traffic-responsive metering system. The system uses an algorithm that calculates metering rates in real time based on systemwide traffic conditions. The algorithm is simple in its approach but very effective in its application. The system has proven to be effective in a series of ongoing evaluations. In this paper, the WSDOT real-time ramp-metering algorithm is described. First a brief description of the Seattle area freeway system and an overview of the development of the ramp metering system are provided. The components of the surveillance, control, and driver information system are then described, followed by a description of the physical elements of the ramp-metering system. After the real-time algorithm used, the limitations of the algorithm, and the advantages of the algorithm are described, the results of an ongoing evaluation effort are presented. Finally, further actions being planned are described.

This paper appears in Transportation Research Record No. 1232, Urban Traffic Systems and Operations. 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

01414228

p. 17-26

1989

Transportation Research Record

0309049601

Figures (7) ; References (4) ; Tables (3)

Algorithms; Centralized traffic control; Components; Measures of effectiveness; Microprocessors; Performance evaluations; Ramp metering; Real time control; Real time data processing

Effectiveness

Highways; Operations and Traffic Management; I73: Traffic Control

TRIS, TRB, ATRI

Jun 30 1990 12:00AM

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