Construction & Materials
Roadway Curve & Superelevation Calculator
Calculate minimum horizontal curve radius and required superelevation rate for a design speed.
Your inputs
Change any value to update the result instantly.
Minimum curve radius
251.9685 m
Superelevation used
6 %
Side friction factor
0.14
Required e at this radius
6 %
Formula and working
R = V² ÷ (127 × (e + f))
- 1
Collect the inputs
Design speed = 80 km/h; Side friction factor f = 0.14; Superelevation rate e = 0.06
- 2
Apply the formula
R = V² ÷ (127 × (e + f))
- 3
Result
Minimum curve radius = 251.9685 m
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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