Vertical Curve Length & Sight Distance Check

Parabolic crest or sag curve based on stopping/headlight sight distance. SI units: m, %, km/h.

1. Curve Type & Sight Distance

Use SSD / headlight sight distance for the design speed.
For reporting only — not used directly in the formulas.

2. Grades & Existing Curve

Upward positive, downward negative.
Algebraic difference A = |g₁ − g₂|.
Optional — leave blank to only get required minimum length.

Rate of vertical curvature: K = L / A, where A = |g₁ − g₂| (%).