00634573

Component

http://onlinepubs.trb.org...trr/1993/1385/1385-017.pdf

https://scholar.google.co...lker&publication_year=1993

The literature on the operational, safety, and capacity aspects of existing two-lane loop ramps is reviewed, and an overview is provided. Using this information, design parameters are suggested until further research is available. Little research information is available on the operation and design of two-lane loop ramps. AASHTO covers single-lane loop ramps very well but does not mention two-lane loop ramps. A TRB literature search indicates that only Georgia has carried out research on two-lane loop ramps. The findings of the Georgia report are discussed along with observations of other two-lane loops in Toronto, Vancouver, and Florida. Generally, directional or semidirectional ramps are preferred for high-volume ramps. They provide more direct travel, easier operation, and higher capacity than loop ramps. However, where there is insufficient space, the two-lane loop ramp is a reasonable compromise. The observations show that two-lane loops operate well where they have good geometric properties. Entrance and exit transitions and ramp widths and curvature all have to be integrated to ensure safe and convenient operation.

This paper appears in Transportation Research Record No. 1385, Intersection and Interchange Design. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01403217

English

p. 133-138

1993

Transportation Research Record

0309054567

Figures (6) ; Photos (7) ; References (2) ; Tables (2)

Curvature; Design; Geometric design; Guides to the literature; Highway capacity; Interchange ramps; Literature reviews; Operations; Traffic safety; Width

Florida; Georgia; Toronto (Canada); Vancouver (Canada)

Florida; Georgia; Toronto (Canada); Vancouver (Canada)

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

TRIS, TRB, ATRI

Aug 30 1993 12:00AM

• ACCESS CONTROL ISSUES RELATED TO URBAN ARTERIAL INTERSECTION DESIGN
• ACCIDENTS AND SAFETY ASSOCIATED WITH INTERCHANGES
• COMPARISON OF SIGHT DISTANCE PROCEDURES FOR TURNING VEHICLES FROM A STOP-CONTROLLED APPROACH
• COORDINATION OF BASIC INTERSECTION DESIGN ELEMENTS: AN OVERVIEW
• DESIGN OF INTERCHANGE AT-GRADE RAMP TERMINALS
• FREEWAY AND INTERCHANGE DESIGN: A HISTORICAL PERSPECTIVE
• GEOMETRIC DESIGN FEATURES OF SINGLE-POINT URBAN INTERCHANGES
• GEOMETRIC DESIGN OF METERED ENTRANCE AND HIGH-OCCUPANCY VEHICLE BYPASS RAMPS
• GRADE-SEPARATED INTERSECTIONS
• HUMAN FACTORS ASSOCIATED WITH INTERCHANGE DESIGN FEATURES
• INTERCHANGE PLANNING AND DESIGN--AN INTERNATIONAL PERSPECTIVE
• INTERCHANGE RAMP GEOMETRICS--ALIGNMENT AND SUPERELEVATION DESIGN
• INTERCHANGE STUDY AND SELECTION PROCESS
• INTERSECTION DESIGN CONSIDERATIONS TO ACCOMMODATE LARGE TRUCKS
• LENGTHS OF LEFT-TURN LANES AT SIGNALIZED INTERSECTIONS
• OPERATIONAL CONSIDERATIONS FOR SYSTEMS OF INTERCHANGES
• RAMP EXIT/ENTRANCE DESIGN--TAPER VERSUS PARALLEL AND CRITICAL DIMENSIONS
• RAMP/MAINLINE SPEED RELATIONSHIPS AND DESIGN CONSIDERATIONS
• SAFE ACCOMMODATION OF PEDESTRIANS AT INTERSECTIONS
• SAFETY IMPROVEMENTS AT INTERSECTIONS ON RURAL EXPRESSWAYS: A SURVEY OF STATE DEPARTMENTS OF TRANSPORTATION