Chapter 14.1, Problem 25E

Curve speeds One method traffic planners use to calculate recommended curve speeds for trucks is with the formula

$S=\sqrt{\frac{15R(112-0.66V+0.091V^2+10B)}{100+1.36R}}$ where S is the recommended curve speed in mph, R is the radius of the curve (in feet), V is the average truck speed on the straight approaching the curve (in mph), and B is the banking of the curve (as a percent). Find the recommended curve speed if the radius is 195 feet, the average approach speed is 60 mph, and the curve banking is 10% (Source: Car and Driver, June 2016).