00715008

Component

http://onlinepubs.trb.org...trr/1995/1500/1500-024.pdf

https://scholar.google.co...szcz&publication_year=1995

The required length of left-turn lanes at unsignalized intersections of two-lane roadways is analyzed, and recommended lengths are presented for different conditions. Increasing volumes of turning movements along suburban roadways due to residential and commercial developments warrant an analysis of the adequate length of turn lanes. The existing guidelines and standards for determining lane lengths at unsignalized intersections are incomplete, and the practices of various state agencies are not uniform. A model is developed which calculates the probability that a given length of turning lane will result in overflows. Lane lengths are suggested such that the probability of lane overflow is less than a given threshold value. The parameters considered in the model are the volume of turning vehicles, volume of opposing vehicles, critical gap, threshold probability, and vehicle mix. The validity of the model is checked by computer simulation. The recommended lengths are compared with lengths suggested by AASHTO, and the effects of considering opposing volume and changing the values of the threshold probability are discussed. The results of a field survey on the required space per vehicle in the turn lane are also presented. Recommended lane lengths for various conditions are presented in a set of tables.

This paper appears in Transportation Research Record No. 1500, Geometric Design, Roadside Safety Features, Roadside Hardware Monitoring, and Scenic Loop Tours. 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

01399820

English

p. 193-201

1995

Transportation Research Record

Figures (4) ; References (10) ; Tables (8)

Alternatives analysis; Field studies; Left turn lanes; Length; Overflows; Recommendations; Traffic simulation; Two lane highways; Unsignalized intersections; Validity

Design; Highways; Research; I20: Design and Planning of Transport Infrastructure

TRIS, TRB

Dec 26 1995 12:00AM

• CALIBRATING AND VALIDATING TRAFFIC SIMULATION MODELS FOR UNCONVENTIONAL ARTERIAL INTERSECTION DESIGNS
• CLEAR ZONE REQUIREMENTS FOR SUBURBAN HIGHWAYS
• CONSISTENCY OF HORIZONTAL ALIGNMENT FOR DIFFERENT VEHICLE CLASSES
• DEVELOPMENT AND IMPLEMENTATION OF AN AUTOMATED FACILITY INVENTORY SYSTEM
• DEVELOPMENT OF EVALUATION CRITERIA FOR LOOP TOURS
• DEVELOPMENT OF GUARDRAILS FOR HIGH-SPEED COLLISIONS
• DEVELOPMENT OF VARIABLE YAW ANGLE SIDE IMPACT SYSTEM AND TESTING ON DOUBLE THRIE BEAM MEDIAN BARRIER
• ESTIMATING SAFETY EFFECTS OF CROSS-SECTION DESIGN FOR VARIOUS HIGHWAY TYPES USING NEGATIVE BINOMIAL REGRESSION
• EVALUATION OF FLUSH MEDIANS AND TWO-WAY, LEFT-TURN LANES ON FOUR-LANE RURAL HIGHWAYS
• GEOGRAPHIC INFORMATION SYSTEM APPLICATIONS IN THE HEART OF ILLINOIS HIGHWAY FEASIBILITY STUDY
• GEOMETRIC DESIGN FOR ADEQUATE OPERATIONAL PREVIEW OF ROAD AHEAD
• HIGHWAY GEOMETRIC DESIGN CONSISTENCY EVALUATION SOFTWARE
• INVESTIGATION OF OBJECT-RELATED ACCIDENTS AFFECTING STOPPING SIGHT DISTANCES
• PERFORMANCE LEVEL 1 BRIDGE RAILINGS
• PERFORMANCE LEVEL 2 AND TEST LEVEL 4 BRIDGE RAILINGS FOR TIMBER DECKS
• PERFORMANCE LEVEL 3 BRIDGE RAILINGS
• RISK OF ROLLOVER IN RAN-OFF-ROAD CRASHES
• SIGHT DISTANCE ON HORIZONTAL ALIGNMENTS WITH CONTINUOUS LATERAL OBSTRUCTIONS
• SLOTTED RAIL GUARDRAIL TERMINAL
• TANGENT LENGTH AND SIGHT DISTANCE EFFECTS ON ACCIDENT RATES AT HORIZONTAL CURVES ON RURAL TWO-LANE HIGHWAYS
• TRAVEL EFFICIENCY OF UNCONVENTIONAL SUBURBAN ARTERIAL INTERSECTION DESIGNS
• TRIPLE T: TRUCK THRIE BEAM TRANSITION
• TURNING VEHICLE SIMULATION: INTERACTIVE COMPUTER-AIDED DESIGN AND DRAFTING APPLICATION