In order to supplement your knowledge about the various concepts
within Geometric Design, and in order to give you a glimpse of how these various topics
are discussed in the professional environment, we have included selected excerpts from
professional design aids. All of the excerpts within this chapter come from the 1994
edition of A Policy on Geometric Design of Highways and Streets, which was
developed by the American Association of State Highway and Transportation Officials
(AASHTO). This particular reference book is widely referenced in the field of
Geometric Design, and consequently, we felt justified in using it repeatedly.
Sight Distances
Brake Reaction Time
Braking Distance
Stopping Sight Distance
Decision Sight Distance
Passing Sight Distance
Horizontal Alignment
Horizontal Alignment Design Suggestions
Superelevation
Side-Friction
Minimum Radius
Horizontal Curve Sight Distance
Transition Segments
Vertical Alignment
Vertical Alignment Design Suggestions
Ascending Grades
Descending Grades
Crest Vertical Curves
Sag Vertical Curves
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