If L is the length of a moving vehicle and R is the radius of curvature the extra mechanical widening to be provided on horizontal curves for single lane is
1
\(\frac{{\rm{L}}}{{2{\rm{R}}}}\)
2
\(\frac{{{{\rm{L}}^2}}}{{2{\rm{R}}}}\)
3
\(\frac{{{{\rm{L}}^3}}}{{2{\rm{R}}}}\)
4
\(\frac{{2{\rm{L}}}}{{{{\rm{R}}^2}}}\)