Design of Horizontal Alignment:
Various design element to be considered in the horizontal alignment are:
- Design speed
- Type and length of transition curve
- Width of pavement
- Super elevation
- Radius of circular curve
- Set back distance
Note: This topic is part of the second chapter of Highway Engineering. I suggest reading this topic in the context of the complete chapter: Geometric Design of Highway. If you want to read the entire Highway Engineering, click here: Highway Engineering.
Design Speed:
- The design speed is main factor on which most of the geometric design element depends including horizontal elements.
- The design is speed of road depends, upon class of road and terrain.
- Classification of terrain & design speed for different class of road is as follows:
- Design speeds are also being defined for urban roads.
- Two values of speed is ruling and minimum are being specified for each type of Road.
- As far as possible, attempt most to be made to design all the geometric element for ruling speed however it site conditions and economic consideration does not permit so, design must be done for minimum design speed.
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