Stopping Sight Distance Calculator

Calculate the minimum distance needed to perceive a hazard and bring a vehicle to a complete stop safely.

Speed Parameters
km/h
Typical range: 30-120 km/h (20-75 mph)
Reaction Parameters
1.0 sec 2.5 sec 5.0 sec
Default: 2.5 sec (AASHTO recommendation)
Vehicle & Road Parameters
%
Positive for uphill, negative for downhill
Advanced Options
Tip: Hover over labels for more information.

Stopping Sight Distance Result

0 meters
Notes & Recommendations
  • SSD is critical for determining minimum curve radii and crest vertical curve design.
  • For downgrades steeper than 3%, increase SSD by 20-30%.
  • In poor weather conditions, consider increasing the coefficient of friction by 20%.
  • For design speeds over 100 km/h (60 mph), use 2.5-3.0 sec reaction time.