01046207

Component

https://doi.org/10.3141/2023-02

http://scholar.google.com...ayed&publication_year=2007

The operational performance of signalized intersections can be significantly affected by heavy left-turn movements. Therefore, several measures to improve the performance of intersections with heavy left-turn movements, including some unconventional schemes, have been investigated. In this paper the performance of two of these unconventional schemes, namely, the crossover displaced left-turn (XDL) intersection and the upstream signalized crossover (USC) intersection, is compared. The XDL intersection eliminates left-turn opposing conflicts by displacing the left-turn lane to the opposing direction and crossing the left-traffic to the left side of the road before the intersection. The USC intersection eliminates left-turn opposing conflicts by crossing both the left and through traffic to the left side of the road before the intersection. The microsimulation software VisSim was used to analyze the two unconventional intersections for comparison. The analysis showed that the XDL outperforms the conventional intersection under various volume scenarios. In contrast, the USC outperforms the conventional intersection under moderate- and high-volume conditions or in the existence of extremely heavy left-turn movements. The results showed that the USC and the XDL exhibit similar average delays in low-, moderate-, and moderately high-volume conditions, with the XDL slightly outperforming the USC. However, the XDL significantly outperforms the USC under high-volume scenarios. The XDL has, as a basic design element, a left-turn bay that extends between the primary and the secondary intersections. The existence of this bay is probably the main reason for the high capacity of the XDL. Such an additional bay requires more right-of-way and higher construction costs than USC.

01088318

English

pp 10-19

2007

Transportation Research Record: Journal of the Transportation Research Board

9780309104500

Print

Figures (13) ; References (11) ; Tables (2)

Highway capacity; Highway operations; Left turns; Performance; Signalized intersections; Traffic control; Traffic delays; Traffic volume

VISSIM (Computer model)

Crossover displaced left turn intersections; Upstream signalized crossovers

Design; Highways; Operations and Traffic Management; I20: Design and Planning of Transport Infrastructure; I73: Traffic Control

TRIS, TRB, ATRI

Feb 8 2007 4:42PM

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