Vertical Curve Length Calculator
Constant-curvature parabolic grade transition with independently set curvature bound; not sight-distance or minimum highway-code design. Caller independently establishes units, regime, calibration and applicability; this does not establish design-code compliance, authenticity, operational safety, treatment efficacy or a validated forecast.
Description
A grade change divided by a permitted curvature gives a conditional vertical-curve length.
A grade change divided by a permitted curvature gives a conditional vertical-curve length.1
The curvature criterion must be selected independently for the road and design context. Use this tool to calculate vertical Curve Length from the supplied measurements and assumptions.
When to use Vertical Curve Length Calculator
Use this tool to calculate vertical Curve Length from the supplied measurements and assumptions. Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
How to use Vertical Curve Length Calculator and understand its results
- Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
- Enter callerAlgebraicGradeDifferenceFraction, callerMaximumVerticalCurvaturePerM, using the field meanings and rules below, then run the tool.
- Read curvatureLimitedParabolicCurveLengthM. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| callerAlgebraicGradeDifferenceFraction | Caller algebraic grade difference fraction | number | Required |
| callerMaximumVerticalCurvaturePerM | Caller maximum vertical curvature per m | number | Required |
Enter finite signed fractional grade change and positive maximum curvature per meter. Return absolute grade change divided by curvature. Zero change gives zero length; no minimum length, sight-distance test or code criterion is installed.
lengthM=abs(gradeChangeFraction)/callerMaximumCurvaturePerM Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| curvatureLimitedParabolicCurveLengthM | Curvature Limited Parabolic Curve Length M; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"callerAlgebraicGradeDifferenceFraction": 0.04,
"callerMaximumVerticalCurvaturePerM": 0.002
},
"output": {
"curvatureLimitedParabolicCurveLengthM": 20
}
}Limitations and assumptions
The curvature criterion must be selected independently for the road and design context. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Passing Sight Distance Calculator for this related task: A passing-distance screen combines opposing and passing speeds over a maneuver time.
Use Intersection Sight Distance Calculator when its separate inputs and assumptions fit the question: A sight-distance screen compares available distance with speed times an accepted time gap.
References
-
Vertical Curve Length Calculator — tool.io
Similar or alternative tools
- Passing Sight Distance Calculator
A passing-distance screen combines opposing and passing speeds over a maneuver time.
- Intersection Sight Distance Calculator
A sight-distance screen compares available distance with speed times an accepted time gap.