SIGHT DISTANCE ON HORIZONTAL ALIGNMENTS WITH CONTINUOUS LATERAL OBSTRUCTIONS
For safe and efficient highway operation, sight distance has been of great interest to researchers in the field of highway geometric design. Several formulas have been developed to relate the available sight distance to the horizontal and vertical alignment of the highway and the existing obstructions. Among these formulas is the one presented by AASHTO to determine the available sight distance on a simple horizontal curve with a length greater than the sight distance. For shorter curves in which the sight distance is greater than the curve length, other methods have been developed. However, none of these methods considered the case of continuous lateral obstructions or complicated horizontal alignments. Consequently, it has been recommended that the available sight distance be checked graphically or in the field. For this study, general analytical procedures were developed to check the available sight distance on horizontal alignments with single and continuous obstructions. A horizontal alignment may consist of any combination of horizontal components, such as straight segments, circular curves, and spiral curves. Based on the analytical procedure, a computer software program was developed to establish the no-passing zones on two-lane highways, according to the specifications used by the Ministry of Transportation of Ontario, Canada. The developed procedures and computer software proved to be very accurate. Using them would save time and effort and would avoid possible human errors when the sight distance is checked using current graphical or field techniques. The computer software can also be used to develop design tables and charts for the available sight distance on different horizontal alignments.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/03611981
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Supplemental Notes:
- This paper appears in Transportation Research Record No. 1500, Geometric Design, Roadside Safety Features, Roadside Hardware Monitoring, and Scenic Loop Tours. 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
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Authors:
- Hassan, Yasser
- Easa, Said M
- Abd El Halim, A O
- Publication Date: 1995
Language
- English
Media Info
- Features: Figures; References; Tables;
- Pagination: p. 31-42
- Monograph Title: Geometric design, roadside safety features, roadside hardware monitoring, and scenic loop tours
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Serial:
- Transportation Research Record
- Issue Number: 1500
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Accuracy; Alignment; Curves (Geometry); No passing zones; Sight distance; Software; Two lane highways
- Uncontrolled Terms: Horizontal alignment; Horizontal curvature
- Old TRIS Terms: Continuous lateral obstructions
- Subject Areas: Design; Highways; I20: Design and Planning of Transport Infrastructure;
Filing Info
- Accession Number: 00714989
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Dec 26 1995 12:00AM