01558242

Component

https://doi.org/10.3141/2486-07

This paper develops decision assistance curves (DACs) to compare delay-based performance measures for three indirect left-turn (ILT) intersections—median U-turn, continuous-flow intersection, and jughandle—relative to a conventional signalized intersection. The DACs consist of two graphical tools: (a) a DAC classifier and (b) two sets of DAC contours. DAC classifier plots are used to select the intersection type that produces the minimum system average delay for a specified main and cross-street volume configuration. DAC contour plots are used to estimate the system average delay difference between a chosen ILT and a conventional signalized intersection and to estimate the increase in average delay compared with a conventional signalized intersection for the movement most negatively affected. These tools can be used by planners, engineers, or other decision makers to identify visually the intersection type that provides the least average system delay under given volume conditions and estimated trade-offs for specific intersection types. The conventional signalized intersection, with protected left turns, was never optimal under studied scenarios. This finding implies that, for all the studied conditions, at least one ILT or permitted left-turn alternative produces lower delay than the conventional signalized intersection.

01582968

15-5482

English

pp 54–63

2015

Transportation Research Record: Journal of the Transportation Research Board

9780309369220

Print

Figures (9) ; References (25) ; Tables (1)

Alternatives analysis; Analysis; Decision support systems; Intersections; Left turns; Performance measurement; Traffic delays; Traffic volume; U turns

Design; Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control

TRIS, TRB, ATRI

Dec 30 2014 1:51PM

• Analysis of Vehicle Speeds and Speed Differentials in Curves
• Design Criteria for Minimum Passing Zone Lengths: Operational Efficiency and Safety Considerations
• Economic Assessment of Access Management Projects in the Houston, Texas, Region
• Effect of Stopping Sight Distance on Crashes at Crest Vertical Curves on Rural Two-Lane Highways
• Empirical Evaluation of J-Turn Intersection Performance: Analysis of Conflict Measures and Crashes
• Influences of Cross-Sectional Design Elements at Urban Arterial Driveway Locations
• Pedestrian and Bicyclist Accommodations and Crossings on Superstreets
• Safety Evaluation of Diverging Diamond Interchanges in Missouri
• Use of Access Travel Time to Estimate the Impact of Driveway Restrictions on Corner Lot Developments