Highway Engineering

Intermediate sight distance (ISD): On a horizontal curve, the requirement of overtaking sight distance can not always be satisfied. In such cases overtaking is prohibited by using regulatory signs. To provide an opportunity for overtaking operation on horizontal curves or in restricted areas, we provide intermediate sight distance, i.e. equals to twice of stopping sight […]

Overtaking Sight Distance (OSD): If all the vehicle ply on the road at the design is speed, then theoretically there would be no need for overtaking, but practically it never happens, hence vehicle moving at design speed, has to overtaken the slow moving vehicle. The minimum distance open to the vision of the driver of

Stopping Sight Distance (SSD): The minimum distance visible to a driver ahead to safety stop a vehicle travelling at design speed without collision with any other obstruction is termed as “SSD”. It is also termed as “Absolute Minimum Sight Distance” or ” Non-Passing Sight Passing”. The stopping distance of vehicle include: Lag Distance () Braking

Sight Distance: Sight distance is the length of road visual a head to the driver at any distance. ( it is considered by taking the height of eyes of the driver to be 1.2 m and height of object to be 0.15 m). Restriction to the visibility/sight distance maybe caused in the following cases: At

Roadway / Width of Formation: It is the sum of with pavement or carriageway including separator (if any) and the shoulder. Roadways width is the top of highway embankment or bottom width of highway cutting excluding the side drain. Width of Formation of various class of Road are as follows: Right of Way / Road

Shoulder: Extra width provided adjacent to edge of pavement is called shoulder. It is provided for emergency point of view like Breakdown of vehicle, medical emergency etc.   As per IRC Minimum width of shoulder required for a highway is 2.5 meter. Cross slope of shoulder should be 0.5% more than cross slope of adjoining

Divider /Medians / Traffic separators Divider is an element provided to Road along the center line to separate two way traffic. The main function of median is to prevent “Head on collision” between vehicles moving in the opposite direction. it also serves following other functions: To channelize traffic into the streams. To protect the pedestrians.

Camber / Cross- Slope: It is the slope provide to the road surface in the transverse direction to drain the rainwater from the road surface to avoid the following: Stripping of bitumen from the aggregate in the presence of the water. In order to avoid swelling of sub grade in case water seeps up to

Pavement surface characteristic Pavement surface characteristic depends upon pavement type. Which in turn depends on availability of material, cost, composition of traffic, climate conditions, method of construction available.Pavement surface characteristics include: Skid and Slip Friction Unevenness Index Light Reflecting Characteristic Drainage (i) Skid and Slip: Skidding take place when there longitudinal moment of wheel is

Elements Of Highway Geometric Design: In Geometric design of highway deals with following elements like Cross-section element, Sight distance, Horizontal alignment details, Vertical alignment details, Intersection details. Cross-section element. Sight distance. Horizontal alignment details. Vertical alignment details. Intersection details. 1.Cross-Section Elements: These are the features of the cross-section of the pavement that effects the life

Geometric design of highway: Geometric design of highway deals with the all the dimensions and layout of visual features of highway such that it provides maximum efficiency and minimum cost and reasonable safety. The geometric design of a highway depends on several design factor. The important of these factor which control the geometric elements are: