00396831

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http://onlinepubs.trb.org...s/trr/1984/971/971-003.pdf

https://scholar.google.co...reed&publication_year=1984

A study of intersection signal optimization in a medium-sized city indicated that there were a large number of approaches without an exclusive left-turn lane, but rather with a shared left and through lane. The study also found that the accurate determination of the capacity of a shared left-turn lane was critical to the analysis of intersection performance. Moreover a search of the literature suggested that there are no current methods of estimating the capacity of an approach containing a shared left-turn lane. A method is proposed for estimating the capacity of a shared left-turn lane. The method builds on the existing procedures for exclusive left-turn lanes first developed by the British in 1966 and since extended in Australia and the United States. The proposed method develops an estimate of the flow of through vehicles during the initial part of the green display when left-turn vehicles are blocked by the opposing flow. Subsequent gap acceptance behavior is modeled to reflect the length of the displayed-green time. Finally, the flow after green is modified to reflect the probability of the shared left-turn lane actually being blocked when the green ends. The resulting capacities compare favorably with results quoted in the literature for cases where conditions in a shared left-turn lane are similar to those in an exclusive left-turn lane situation. The results are given both in tabular form and as a set of iterative equations.

Publication of this paper sponsored by Committee on Highway Capacity and Quality of Service. 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

00452357

HS-038 729

pp 14-20

1984

Transportation Research Record

0309037530

Print

Figures (3) ; References (9) ; Tables (3)

Equations; Gap acceptance; Iterative methods; Left turn lanes; Left turns; Regulatory signs; Signalized intersections; Through traffic; Traffic equivalence factor; Traffic flow

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Highways; Operations and Traffic Management; I71: Traffic Theory

HSL, TRIS, TRB

Jan 31 1986 12:00AM

• ANALYSIS OF UNSIGNALIZED INTERSECTION CAPACITY
• ANOTHER LOOK AT STORAGE REQUIREMENTS FOR BANK DRIVE-IN FACILITIES
• AUTOMATED COLLECTION OF VEHICULAR DELAY DATA AT INTERSECTIONS
• CAPACITY, SPEED, AND PLATOONING VEHICLE EQUIVALENTS FOR TWO-LANE RURAL HIGHWAYS (DISCUSSION ANDD CLOSURE)
• COMPUTER SIMULATION TO COMPARE FREEWAY IMPROVEMENTS (ABRIDGMENT)
• DEVELOPMENT AND APPLICATION OF A MACROSCOPIC MODEL FOR RURAL HIGHWAYS
• DISCONTINUITY IN EQUILIBRIUM FREEWAY TRAFFIC FLOW
• DYNAMIC FREEWAY SIMULATION PROGRAM FOR PERSONAL COMPUTERS
• EVALUATING CAPACITIES OF ONE-LANE ROADS WITH TURNOUTS
• INVESTIGATION OF NETWORK-LEVEL TRAFFIC FLOW RELATIONSHIPS: SOME SIMULATION RESULTS
• LEVEL OF SERVICE CONCEPTS: DEVELOPMENT, PHILOSOPHIES, AND IMPLICATIONS
• PASSENGER CAR EQUIVALENTS FOR UNINTERRUPTED FLOW: REVISION OF CIRCULAR 212 VALUES
• ROLE OF ADAPTIVE DISCRETIZATION IN A FREEWAY SIMULATION MODEL
• SIGNALIZED INTERSECTION DELAY MODELS--A PRIMER FOR THE UNINITIATED
• SIMULATION OF TRAFFIC PERFORMANCE, VEHICLE EMISSIONS, AND FUEL CONSUMPTION AT INTERSECTIONS: THE TEXAS-II MODEL
• SIMULATION STUDY OF GUIDELINES FOR RURAL ROAD IMPROVEMENTS
• USE OF THE NCHRP SIGNALIZED INTERSECTION CAPACITY METHOD--A SOUTH AFRICAN EXPERIENCE
• VEHICLE-DETECTOR INTERACTIONS AND ANALYSIS OF TRAFFIC-ACTUATED SIGNAL CONTROLS