INVESTIGATION OF OBJECT-RELATED ACCIDENTS AFFECTING STOPPING SIGHT DISTANCES
Stopping sight distance (SSD) is an integral part of the highway design process because it is the minimum sight distance required at all points along the roadway. The current SSD model uses a critical sight distance situation in which the driver detects a small object in the roadway, recognizes it as a hazard, and stops before striking it. Some researchers have questioned the assumptions and variables used in the SSD model because they do not appear to represent a realistic, real-world situation when combined in the existing model. The 150-mm (6-in.) object is one of these questionable variables because this height was not based on the probability of encountering such an object in the roadway environment. The objective of this research was to investigate the characteristics of objects encountered in the roadway that represent a realistic hazard for the driver. A detailed examination of accident data was performed to evaluate the characteristics. Three types of accidents in two states were studied: other-object, animal, and evasive action. The study results showed that only 0.07% of the reportable accidents involved small objects in the roadway. More than 90% of these objects accidents occurred at night on straight, flat roadways (conditions in which sight distance is not limited by the roadway's geometry), and they did not result in serious injuries. These findings suggest that accidents with small objects are neither frequent enough nor severe enough to justify their use as the critical situation in the SSD model. The authors recommend that the object height used in the design should represent the smallest object that poses a hazard to the driver: the minimum legal taillight height of a vehicle.
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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:
- Kahl, Karen B
- Fambro, Daniel B
- Publication Date: 1995
Language
- English
Media Info
- Features: References; Tables;
- Pagination: p. 25-30
- 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: Computer models; Crash data; Crash investigation; Hazards; Height; Highway design; Recommendations; Stopping sight distance
- Uncontrolled Terms: Hazard perception
- Old TRIS Terms: Object in the roadway
- Subject Areas: Design; Highways; Research; Safety and Human Factors; I20: Design and Planning of Transport Infrastructure; I82: Accidents and Transport Infrastructure;
Filing Info
- Accession Number: 00714988
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Dec 26 1995 12:00AM