DESIGN SPEED: - The design speed is the most important factor
controlling the geometric design elements of highway. The design speed is
decided taking into account the overall requirements of the highway. Design of
almost every geometric design element of a road is dependent on the design
speed. For example, the cross sectional element of a road such as width and
clearance requirements, the sight distance requirements, the horizontal
alignment elements such as radius of curve, super elevation etc. I.R.C
recommended different design speed in km/hour is as:
|
SN |
TYPES OF ROAD |
PLAIN ROAD |
MOUNTANIOUS ROAD |
||
|
General |
Minimum |
General |
Minimum |
||
|
1 |
National
and State Highway |
100 |
80 |
50 |
40 |
|
2 |
Main
District Road |
80 |
65 |
40 |
30 |
|
3 |
Other
District Road |
65 |
50 |
30 |
25 |
|
4 |
Village
Road |
50 |
40 |
25 |
20 |
An overpass (called a flyover in the United Kingdom and
some other Commonwealth is a bridge, road, railway or
similar structure that crosses over another road or railway. An overpass and underpass together
form a grade separation.[1] Stack interchangesare made up of many
overpasses.