Question

The mechanical widening and psychological widening on a two lane highway curve of 80 m radius for a vehicle having wheel base of 7 m are equal. The design speed for the highway is ___________kmph.

• A. 68.06
• B. 26.02
• C. 52.04
• D. 59.02

Answer 1

The correct option is C 52.04

Mechanical widening = Psychological widening

$\frac{n{l}^2}{2R}=\frac{V}{9.5\sqrt{R}}$
$\frac{2\times 7^2}{2\times 80}=\frac{V}{9.5\sqrt{80}}$
$V=52.04kmph$