ROAD GEOMETRICS

Road Geometrics means fixing up of visible dimension of a road so that the traffic could utilize it conveniently for its safe and comfortable movements.

Road Geometrics include the following features

a)  Cross-section elements such as formation width, carriage way, camber, gradient etc.

b) Sight distance considerations such as stopping and passing sight distance

c) Horizontal and Vertical alignment including transition curves and super elevation

Although the road geometrics are greatly influenced by topography of land, locality or area and traffic requirements, but design speed is the most important controlling factor in the geometric design of highways.

Various elements of road geometrics are

i)     Right of way        

ii)    Formation width

iii)   Road Margin        

iv)   Road shoulder

v)    Carriage way

vi)   Side slopes

vii) Kerbs       

viii)      Formation level

ix)   Camber    

x)    Gradient

xi)   Design and average running speed

xii) Stopping and passing sight distances

xiii)      Horizontal, vertical and transition curves

xiv)      Super elevation

Some of the above elements of road geometrics is embankment and cutting are described below

 

 

 (a) Cross-section of road in filling showing elements of road geometrics

 

(b) Cross-section of road in cutting showing elements of road geometrics