Overtaking Sight Distance:
Overtaking sight distance is calculated on the assumption that the overtaking vehicle (i) travels behind the overtaken vehicle to perceive the clear road ahead, (ii) accelerates to the design speed, overtakes the vehicle, and returns to the original lane, with a safe margin of distance between it and the opposing vehicle. Table 5 gives the values recommended by IRC.
Table: Overtaking Sight Distance
The overtaking sight distance is measured between two points both 1.2 m above the carriageway, representing the position of the eye of the driver and the object.