The minimum radius of the curve to the vehicle to provide safe travel is 2339.2 ft
Step-by-step explanation:
Given -
Speed allowed, v = 70mph
1 mph = 1.467 fps (feet per second)
Therefore, v = 70 X 1.467 fps
Superelevation, e = 0.05 inches/inch
Coefficient of side friction, fs = 0.09
Minimum radius of the curve, r = ?
We know,
r = v² / g ( fs + e/100 )
where,
g = acceleration due to gravity in feet
g = 32.2 lb.ft / lbf.s²
r = ( 70 X 1.467 )² / 32.2 ( 0.09 + 0.05 )
r = 2339.2 ft
Therefore, the minimum radius of the curve to the vehicle to provide safe travel is 2339.2 ft