Author(s):
J.C. Glennon
Publication Date
August 1969
Abstract
An examination of the state of knowledge was conducted for the purpose of evaluating design criteria for safe stopping sight distance. The evaluation was specifically concerned with driver perception-reaction time, design friction factors, assumed speeds for design, driver's eye height, and object height. The evaluation was addressed to design criteria as presented in "A Policy on Geometric Design of Rural Highways, 1965," by the AASHO. The major findings were:|· Driver perception-reaction time may be higher than the assumed 2.5 seconds for the higher travel speeds.|· Based on skid trailer measurements on 500 pavements, it was concluded that the AASHO design friction factor values do not represent a critical level of stopping capability.|· The AASHO's "assumed speed for conditions" has no objective basis. Alternative bases are present.|· The present criterion for object height bears no relation to many of the operational requirements for safe stopping sight distance.|· There is a need to design for nighttime stopping sight distance to opposing vehicle headlights on two-lane highways.
Report Number:
134-3
Link(s):
Document/Product
http://tti.tamu.edu/documents/134-3.pdf
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