00605649

Component

http://onlinepubs.trb.org...trr/1990/1287/1287-015.pdf

https://scholar.google.co...ulis&publication_year=1990

The findings of an FHWA project entitled "Levels of Service in Shared, Permissive Left-Turn Lane Groups at Signalized Intersections" are described. The project objective was to evaluate and improve the 1985 Highway Capacity Manual (HCM) model for estimating the impact of shared-permissive left-turn movements on lane group saturation flow. The study was based on a nationwide data collection effort that yielded 1,492 15-min data samples taken for 45 intersection approaches (at 25 intersections) in four regional areas. Field measurements included prevailing and ideal saturation flow rates for each period, critical portions of the green phase as defined in the 1985 HCM, subject and opposing flow rates, lost times, and other critical information. Because of the lack of off-peak-period queues sufficient to yield saturation flow rate measurements, only 22% of the data was used in model evaluations and calibrations. The resulting analysis documents flaws in the 1985 HCM model for the impact of shared, permissive left turns on saturation flow rates, and recommends simplified models that could be used in conjunction with the general analysis procedure of the 1985 HCM. Unique characteristics of single-lane approaches opposed by single-lane approaches are identified, and revised procedures for the analysis both of single-lane and multilane approaches involving shared-permissive left turns are recommended.

This paper appears in Transportation Research Record No. 1287, Traffic Flow, Capacity, Roadway Lighting, and Urban Traffic Systems 1990. 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

01411069

p. 138-150

1990

Transportation Research Record

0309050626

Figures (8) ; References (8) ; Tables (5)

Accuracy; Adjustment factors; Field studies; Level of service; Mathematical models; Multilane highways; Permissive phasing; Saturation flow; Signalized intersections; Single lane traffic; Traffic

Highway Capacity Manual

Field data; Models; Multilane traffic

Highways; Operations and Traffic Management; I71: Traffic Theory

TRIS, TRB

Mar 31 1991 12:00AM

• ADAPTIVE FORECASTING OF FREEWAY TRAFFIC CONGESTION
• CAPACITY AND DELAY ESTIMATION FOR PRIORITY UNSIGNALIZED INTERSECTIONS: CONCEPTUAL AND EMPIRICAL ISSUES
• CAPACITY AND SPEED-FLOW ANALYSIS OF THE QUEEN ELIZABETH WAY IN ONTARIO
• COMBINED EFFECT OF RADIUS AND PEDESTRIANS ON RIGHT-TURN SATURATION FLOW AT SIGNALIZED INTERSECTIONS
• CONFLICT SIMULATION IN INTRAS: APPLICATION TO WEAVING AREA CAPACITY ANALYSIS
• CONGESTION IDENTIFICATION ASPECTS OF THE MCMASTER INCIDENT DETECTION ALGORITHM
• CONSPICUITY OF RETROREFLECTIVE SIGNS AND DEVICES AT NIGHT WHEN DRIVING WITH ONLY ONE HEADLAMP WORKING
• COUNTERBEAM LIGHTING, A PROVEN ALTERNATIVE FOR THE LIGHTING OF THE ENTRANCE ZONES OF ROAD TUNNELS
• DETECTING ERRONEOUS LOOP DETECTOR DATA IN A FREEWAY TRAFFIC MANAGEMENT SYSTEM
• ESTIMATING AVERAGE CYCLE LENGTHS AND GREEN INTERVALS OF SEMIACTUATED SIGNAL OPERATIONS FOR LEVEL-OF-SERVICE ANALYSIS
• ESTIMATING CAPACITY OF AN ALL-WAY-STOP-CONTROLLED INTERSECTION
• FLOW PROCESSES AT A FREEWAY BOTTLENECK
• LATE-NIGHT TRAFFIC SIGNAL CONTROL STRATEGIES FOR ARTERIAL SYSTEMS
• MEASURING DELAY AND SIMULATING PERFORMANCE AT ISOLATED SIGNALIZED INTERSECTIONS USING CUMULATIVE CURVES
• MEASURING LEVEL OF SERVICE OF TWO-LANE HIGHWAYS BY OVERTAKINGS
• MODEL OF TURNING MOVEMENT PROPENSITY
• MULTIBAND--A VARIABLE-BANDWIDTH ARTERIAL PROGRESSION SCHEME
• ON-LINE DIVERSION PREDICTION FOR DYNAMIC CONTROL AND VEHICLE GUIDANCE IN FREEWAY CORRIDORS
• PREDICTION OF TRAFFIC FLOW BY AN ADAPTIVE PREDICTION SYSTEM
• SIMULTANEOUS OPTIMIZATION OF SIGNAL SETTINGS AND LEFT-TURN TREATMENTS
• TESTING AND FIELD IMPLEMENTATION OF THE MINNESOTA VIDEO DETECTION SYSTEM (AUTOSCOPE)
• TRAFFIC CONFLICT VALUES FOR THREE-LEG, UNSIGNALIZED INTERSECTIONS
• TRAFFIC SIGNAL DELAY MODEL FOR NONUNIFORM ARRIVALS
• WASHINGTON STATE UNIVERSITY PARKING ACTION PLAN--A CAMPUS PARKING CASE STUDY