Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Speed Meters Per Second (m/s)

Required number input.

Gravity Meters Per Second Squared (m/s²)

Required number input.

Radius Meters (m)

Required number input.

Lateral Friction Factor

Required number input.

Uncapped road-curve superelevation estimate e=v²/(gR)−f from speed, radius and assumed lateral friction; not a design-code limit. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Superelevation Ratio

The resulting superelevation ratio returned as a number.

• Road geometry, pavement loading, sight distance, superelevation, and traffic estimates depend on jurisdictional criteria, design speed, vehicles, grade, friction, climate, drainage, growth, human factors, and survey data. Apply the current road authority standard.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Horizontal Curve Radius

  Minimum ideal level-curve radius for specified speed and combined superelevation plus lateral friction: R=v²/[g(e+f)].

• Wind Pressure

  Unfactored dynamic wind pressure q=½ρv² from supplied air density and wind speed; not a code design load.

• Ampacity Derated

  Adjusted current rating from a base ampacity times a supplied 0–1 derating factor; not a code sizing result.