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Title: TESTING A TRAFFIC CIRCLE FOR POSSIBLE CAPACITY
Accession Number: 00228093
Record Type: Component
Availability: Transportation Research Board Business Office 500 Fifth Street, NW Abstract: THE LATHAM, NEW YORK, TRAFFIC CIRCLE HAS A 200-FT. DIAMETER CENTRAL ISLAND, WITH TWO 15-FT. LANES AND FOUR ENTERING HIGHWAYS. THESE HIGHWAYS ENTER SO AS TO GIVE TWO 210-FT. AND TWO 105-FT. WEAVING SECTIONS MEASURED ON THE CENTER LINE AND FROM CENTER-TO-CENTER OF THE ENTERING HIGHWAYS. A PRELIMINARY CHECK OF THE VOLUMES, FROM THE ANNUAL AUGUST COUNTS, SHOWED LESS THAN 1,000 VPH. THIS WAS NOT ENOUGH TO LOAD THE CIRCLE FOR TESTING CAPACITY. IT WAS THEREFORE DECIDED TO USE 30 TEST CARS ON A 3-MIN. SCHEDULE, IN ADDITION TO REGULAR TRAFFIC. THE PLAN SCHEDULED THE TEST CARS WITH 50 TO 50, 75 TO 25, 90 TO 10 PERCENT WEAVING ACTION WITH TWO SEPARATE TEST ROUTINGS. THE CIRCLE WAS DIVIDED INTO FOUR SEGMENTS FOR STUDYING THE WEAVING ACTIONS IN THE SHORTER AND THE LONGER WEAVING SECTIONS. THREE TESTS WERE TAKEN FOR PERIODS OF 30 MIN. AND TWO FOR 15 MIN. ON THE SHORTER SEGMENTS A AND C WITH ALL CARS WEAVING ON A 50 TO 50 RATIO, THE POSSIBLE CAPACITY WAS ABOUT 1,200 VPH. AND 1,300 VPH. WITH 70 TO 30 WEAVING RATIO. THE MAXIMUM SPEEDS RECORDED IN TRAVELING THROUGH THE SHORTER WEAVING SECTIONS RANGED FROM 16 TO 21 MPH.-THROUGH LANE MOVEMENTS, ALSO WERE RECORDED. ON THE LONGER SEGMENTS B AND D WITH ALL CARS WEAVING ON A 50 TO 50 RATIO, THE POSSIBLE CAPACITY WAS FOUND TO BE ABOUT 1,500 VPH. WITH A ONE-LANE OPERATION AND ABOUT 2,000 VPH. FOR TWO-LANE OPERATION, (TWO-ABREAST). ON A 70 TO 30 RATIO AND ABOVE, WITH ALL CARS WEAVING, THE CAPACITY OF THE WEAVING SECTIONS WERE INCREASED TO 1,700 VPH. FOR ONE- LANE OPERATION AND 2,200 VPH. FOR TWO-LANE OPERATION. THE MAXIMUM SPEEDS RECORDED AT WHICH VEHICLES PASSED THROUGH THE LONGER WEAVING SECTIONS, DURING THE TEST, VARIED FROM 17 TO 24 MPH. /AUTHOR/
Supplemental Notes: Vol 31, pp 415 - 424, 10 FIG, 2 TAB, 1 PHOT. 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.
Monograph Title: Monograph Accession #: 01490421
Authors: Shrope, E BEditors: Burggraf, FredCarey Jr, W NMiller, Walter JPublication Date: 1952
Serial:
Highway Research Board Proceedings
Volume: 31 Media Type: Digital/other
TRT Terms: Subject Areas: Highways; Operations and Traffic Management
Files: TRIS, TRB
Created Date: Aug 8 1971 12:00AM
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