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 traveling at a certain speed after detecting a hazard. The model proposed by the American Association of State Highway and Transportation Officials (AASHTO) is given by S= V^2/2g(f±G) + TV

where
S =stopping sight distance (ft)
V= initial speed (ft Is)
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)

Required:
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.