00983188

Component

https://doi.org/10.3141/1881-06

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

At signalized intersections with opposing left-turn lanes, inadequate sight distance of left-turn drivers caused by obstructions from opposing left-turn vehicles can not only contribute to a serious safety problem due to drivers misjudging the gaps in the opposing through traffic but also cause increased intersection delay. This delay is created because drivers need more time to make sure that the opposing through lanes are clear. The 2001 AASHTO manual pointed out that the typical poor visibility of opposing through traffic usually occurs at signal intersections with medians wider than 18 ft and recommended two improvement methods: creating parallel offset left-turn lanes and tapered offset left-turn lanes. However, AASHTO did not provide the specific design guideline, nor did it present the related geometric design model. Sight-distance geometric models for unprotected left-turning vehicles from the major road onto the minor road at signalized intersections and vision improvement effects of the two offset methods were developed, and the relationship between available sight distance and related intersection geometric parameters was analyzed.

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

00983182

English

p. 46-53

2004

Transportation Research Record

0309094771

Figures (7) ; References (11) ; Tables (4)

Geometric design; Left turn lanes; Opposing traffic; Sight distance; Signalized intersections; Traffic delays; Traffic safety

Offset 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
• HIGHWAY DESIGN CONSISTENCY: REFINING THE STATE OF KNOWLEDGE AND PRACTICE
• INFLUENCE OF SPEEDS ON DESIGN STANDARDS IN SWITZERLAND
• LENGTHS OF DOUBLE OR DUAL LEFT-TURN LANES