00983191

Component

https://doi.org/10.3141/1881-09

http://scholar.google.com...orty&publication_year=2004

Double (or dual) left-turn lanes (DLTLs) are a relatively new geometric feature, and the literature on their design parameters is limited. The effectiveness of the DLTL in improving the operation of an intersection depends on several design parameters; among them, the most critical is the length of the DLTL. A procedure for determining the length of the DLTL was developed. First, the procedure surveys how drivers choose a lane of the DLTL in the real world and analyzes the relationship between lane use and the volume of left-turn vehicles. Second, the procedure formulates the probability that all arriving left-turn vehicles during the red phase can enter the left-turn lanes; this means no overflow of left-turn vehicles from the DLTL and no blockage of the entrance of the DLTL by the queue of through vehicles. This probability is presented as a function of the length of the DLTL and the arrival rates of left-turn and through vehicles. The adequate lane length is derived such that the probability of the vehicles entering the DLTL is greater than a threshold value. Third, the adequate length is expressed in number of vehicles; later, this value is converted to the actual distance required on the basis of the vehicle mix and preference between the two lanes. Recommended lengths are presented as a function of left-turn and through volumes for practical application. The proposed approach is unique in that it avoids lane overflow and blockage of lane entrance.

This paper appears in Transportation Research Record No. 1881, Geometric Design and the Effects on Traffic Operations 2004.

00983182

English

p. 72-78

2004

Transportation Research Record

0309094771

Figures (4) ; References (12) ; Tables (2)

Left turn lanes; Length; Traffic volume

Dual left turn lanes

Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure

TRIS, TRB, ATRI

Dec 2 2004 12:00AM

• BASIS OF THE SWISS DESIGN STANDARD FOR ROUNDABOUTS
• DESIGN AND OPERATIONAL PERFORMANCE OF CROSSOVER DISPLACED LEFT-TURN INTERSECTIONS
• DETERMINING CRITICAL LENGTH OF GRADE FOR GEOMETRIC DESIGN OF VERTICAL ALIGNMENTS
• DEVELOPMENT OF THE DISPLACED RIGHT-TURN INTERSECTION
• FUZZY MODEL FOR SAFETY EVALUATION PROCESS OF NEW AND OLD ROADS
• GEOMETRIC MODELS TO CALCULATE INTERSECTION SIGHT DISTANCE FOR UNPROTECTED LEFT-TURN TRAFFIC
• HIGHWAY DESIGN CONSISTENCY: REFINING THE STATE OF KNOWLEDGE AND PRACTICE
• INFLUENCE OF SPEEDS ON DESIGN STANDARDS IN SWITZERLAND