00625328

Component

http://onlinepubs.trb.org...trr/1992/1356/1356-009.pdf

https://scholar.google.co...Saka&publication_year=1992

Sight-distance problems at intersections are often discussed in the context of visual obstructions caused by permanent objects such as trees, parked vehicles, and buildings. Very little investigation has been done on sight-distance problems engendered by queued vehicles. This type of problem poses safety and capacity deficiencies, particularly for unprotected left-turn movements at intersections. The available sight distance for a left-turning motorist on a major approach is shown to be dependent on the offset for opposing left-turn lanes, that is, the distance from the inner edge of a left-turn lane to the outer edge of the opposing left-turn lane. The model developed can be used to determine the minimum offset required for ensuring an adequate sight distance for left-turning traffic, given the design speed and the configuration of the intersection. A sensitivity analysis was undertaken to investigate the effects of changes in the noted offset on the available sight distance for left-turning traffic. It was determined that there was a strong correlation between the offset and the available sight distance for left-turning traffic. It is, therefore, possible to resolve this problem by incorporating in the intersection design some considerations for the minimum offset for opposing left-turning lanes.

This paper appears in Transportation Research Record No. 1356, Operational Effects of Geometrics and Geometric 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

01404971

English

p. 73-79

1992

Transportation Research Record

0309052203

Figures (4) ; References (4) ; Tables (1)

Design; Intersections; Left turn lanes; Left turns; Mathematical models; Offsets (Traffic signal timing); Opposing traffic; Sensitivity analysis; Sight distance

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

TRIS, TRB, ATRI

Nov 16 1993 12:00AM

• COMPARISON OF OPERATIONAL PARAMETERS FOR CONVENTIONAL AND SINGLE-POINT DIAMOND INTERCHANGES
• GEOMETRIC INCONSISTENCIES AND ACCIDENT EXPERIENCE ON TWO-LANE RURAL HIGHWAYS
• GUIDELINES FOR OFFSETTING OPPOSING LEFT-TURN LANES ON FOUR-LANE DIVIDED ROADWAYS
• OPERATIONAL EFFECTS OF NONTRAVERSABLE MEDIANS AND TWO-WAY LEFT-TURN LANES: A COMPARISON
• OPERATIONAL IMPACTS OF WIDER TRUCKS ON NARROW ROADWAYS
• RATIONAL APPROACH FOR GEOMETRIC DESIGN OF SPEED-CONTROL ROAD HUMPS
• ROADWAY DESIGN STANDARDS TO ACCOMMODATE LOW-CLEARANCE VEHICLES (WITH DISCUSSION AND CLOSURE)
• SAFETY EFFECTS OF GEOMETRIC IMPROVEMENTS ON HORIZONTAL CURVES
• SIGHT-DISTANCE DESIGN FOR CURVED ROADWAYS WITH TANGENTIAL INTERSECTIONS