Overtaking Sight Distance | Overview and Calculation

Overtaking Sight Distance (OSD) is the sight distance required for the faster vehicle to overtake the slower vehicle safely.

It depends upon

  • Speed of overtaking vehicle, overtaken vehicle, opposing vehicle (undivided road)

  • Distance between these vehicles

Overtaking Sight Distance Calculation

  • d₁ - Distance covered when we decide to overtake the slow moving vehicle

  • d₂ - Distance covered during overtaking operation

  • d₃ - Distance travelled by opposing vehicle (only in undivided road)


APSEd is an E-learning platform for Civil Engineering by IIT-B Graduates. Get access to all in one place!

  • Video Lectures & Study Material

  • Practice Questions & Mock Tests

  • Exclusive Doubt Support

600+ learners are studying with us. Join them and learn with us for an optimized learning experience. 

APSEd Founders

Hi! I am Aditya, co-founded APSEd with Palaniappan.


Our brain can accumulate and memorize things to a certain extent. Once it is overloaded, some of the facts and formulas you remembered fade away over time.


All this becomes easier once we understand the concept and know how to apply them. This is what we strive to achieve through our courses. 

Our Courses + Your Effort = Success in exams!

Overtaking Zone

When we are not able to provide OSD, we provide some zone (extra lane for certain distance) for vehicles to overtake slow moving vehicles.​​

  • Minimum length of Overtaking Zone = 3 times OSD

  • If overtaking zone cannot be provided, Intermediate sight distance - ISD (2 times SSD) is provided

  • Facebook
  • Twitter
  • YouTube
  • Instagram

Join Us!