A model known as stopping sight distance is used by civil engineers to design roadways....

A model known as stopping sight distance is used by civil engineers to design roadways. This simple model estimates the distance a driver needs in order to stop his car while traveling at a certain speed after detecting a hazard. The model proposed by the American Association of State Highway Officials (AASHO) is given by

where

S = stopping sight distance (ft)

V = initial speed (ft /s)

g = acceleration due to gravity, 32.2 ft /s²

f = coefficient of friction between tires and roadway

G = grade of road

T = driver reaction time (s)

What are the appropriate units for f and G if the preceding equation is to be homogeneous in units? Show all steps of your work.