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Copyright
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(Copyright © 1983, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing) |
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Abstract
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Stopping-sight dístance (sSD) is an irnportant highway design feature. The concept of providing a sufficient length of highway visible to the driver for collision avoiclance is basic to the safe design of highways. floweverr translatíng this eoncept to design stan¿lards and criteria is noÈ as simple as it may appear.
A critieal review of current design practice for SSD is presenteil in this paper. The concepts and conclusions Presented are drawn froin a study of SSD conducteil for FHWA as a Part of a research project entitled, "Effectiveness of Design Criteria for Geometric Elements.
A concept of SSD that focuses on highway operational requirements has been developecl. Shortcomings anil inconsistencies ín AASHTO design policy are revealeil by applying this operational SSD concept. Also, by using sight-distance profiles, additional insights are gained on the relation between sight distance and highway safety.
A basic highway design concept is that the driver should be provided a suffi- cient visible length of highway to enable collision avoidance. Translating this concept to appÌopriate standaÌds and criteria is an important design considera' tion. The concept of safe stopping-sight distance (SSD) as developed by AASHTO is reviewed and discussed, A functional SSD model is offered as a means of demonstÌating shortcomings and inconsistencies in AASHTO design policy. ln addition, the geometry of SSD is evaluated through the use of sight' distance profiles, Significant conclusions are presented that relate to SSD de- sign values on horizontal curves and special problems with trucks on hotizontal curves, The functional SSD model is helpful in understanding accidents at lo- cations that have inadequate SSD.
Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1983/923/923-010.pdf
Language: en |