Definition of Geometric Design :

geometric design of highways deals with the dimensions and layout of visible features of the highway.

Geometric design fulfills the requirements of the driver and the vehicle, such as comfort, efficiency and safety.

Goals of geometric design

• Maximize the comfort, safety and economy of facilities.
• Provide efficiency in traffic operation.
• Provide maximum safety at reasonable cost.
• Minimize the environmental impacts

Factors affecting geometric design :

• Design speed.
• Topography.
• Traffic.
• Environmental factors.
• Economical factors. u
• Vehicles properties (dimensions, weight, operating characteristics, etc.)

Road alignment :

• The position or the layout of the central line of the highway on the ground is called the alignment.
• Horizontal alignment includes straight and curved paths.
• Vertical alignment includes level and gradients.

Pavement design :

A highway pavement is a structure consisting of superimposed layers of processed materials above the natural soil sub-grade.

The pavement must provide an acceptable riding quality, adequate skid resistance, favourable light reflecting characteristics, and low noise pollution.

There are two types of pavements :

  1.rigid pavements.

  2. flexible pavements.

References:

Highway Geometric Design presentation by Khaled Al shami