Design Parameters
km/h
%
-
Curve Geometry
deg
m
Safety Margin
Design vs. Min Radius--
R_min1.25 R_min2.0 R_min
Awaiting Input
Analysis Results
Minimum Radius (R_min)
--m
Design Radius (R)
--m
Tangent Length (T)
--m
Curve Length (L)
--m
External Distance (E)
--m
Radius Safety Margin
--%
Reference Formulas
AASHTO Minimum Radius:
R_min = V² / [g(e + f)]
SI: V in m/s, g=9.807 m/s²
Curve Geometry:
T = R · tan(Δ/2)
L = R · Δ · π/180
E = R · [1/cos(Δ/2) - 1]
e = superelevation, f = side friction, Δ = deflection angle
Horizontal Alignment Plan View
Superelevation Cross-Section
R vs V Safety Envelope