Stopping Sight Distance (AASHTO)
AASHTO Green Book SSD = perception-reaction + braking distance from speed, friction, and grade. State DOT design tables round these numbers.
Formula and source
d_pr = 1.47 * v * t_pr; d_br = v^2 / (30 * (f + g)); d = d_pr + d_br.
AASHTO Green Book (Policy on Geometric Design of Highways and Streets, 7th ed.) Chapter 3.
Audience
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