Double left-turn lanes in medium-size cities

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Journal of Transportation Engineering

DOI:https://doi.org/10.1061/(ASCE)0733-947X(1999)125:2(138)· OSTI ID:330504

Spring, G S ^[1]; Thomas, A ^[2]

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1. Univ. of Missouri, Rolla, MO (United States). Dept. of Civil Engineering
2. North Carolina Dept. of Transportation, Raleigh, NC (United States). Transportation Engineering Branch

Given the increasing use of double left-turn lanes and the lack of methods to design and analyze them, there exists an urgent need to develop such methods. This paper describes work completed at North Carolina A and T State University that expands the scope of previous work done in the area of double left-turn lanes and improves the scientific basis of that work. Double left-turn data from 30 intersections in the city of Greensboro, North Carolina, were analyzed with respect to relationships among performance and geometric characteristics. Results indicate that the overall f{sub LT} of 0.92, recommended by the Highway Capacity Manual, appears reasonable for the inside lane. Values of 0.86--0.88 are more appropriate for outside lane adjustments. The variables causing the most significant changes in performance of double left-turn lanes were traffic related, and not related to geometry. The presence or absence of through traffic and the absence of opposing left-turn flow were key causes of performance changes.

• OSTI ID: 330504
• Journal Information: Journal of Transportation Engineering, Journal Name: Journal of Transportation Engineering Journal Issue: 2 Vol. 125; ISSN JTPEDI; ISSN 0733-947X
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ENERGY CONSERVATION
PERFORMANCE TESTING
TRAFFIC CONTROL
URBAN AREAS