Road alignment Radius of Curvature check according to design speed

IRC Horizontal Geometry Checker

Plain (100 km/h) Rolling (80 km/h) Mountainous (50 km/h) Steep (40 km/h)

Point	Longitude	Latitude	Radius (m)	Superelevation (%)	Transition Length (m)	Status

User Guide: IRC Road Alignment Compliance Checker

Automated Geometric Design Evaluation Tool

This tool analyzes road centerlines from KML files to verify alignment parameters against standard IRC (Indian Roads Congress) design criteria. It computes curve radius, required superelevation, and transition spiral lengths in real-time.

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IRC Design Standards Applied

The tool evaluates your spatial data using a local coordinate projection ($R = 6,371\text{ km}$) and quadratic regression curves over a sliding 11-point mathematical window. The design thresholds are structured as follows:

Terrain Classification	Design Speed ($V$)	Min. Permissible Radius ($R_{min}$)	Max. Superelevation ($e_{max}$)
Plain	100 km/h	360 meters	7.00%
Rolling	80 km/h	230 meters	7.00%
Mountainous	50 km/h	90 meters	7.00%
Steep	40 km/h	60 meters	7.00%

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Step-by-Step Instructions

STEP 1

Select your project's geography type using the Terrain drop-down menu. This loads the correct speed parameters and geometric rulesets.

STEP 2

Click on Choose File / Upload KML and provide your file containing the path string.
*Note: The path alignment must contain at least 11 survey coordinate points to enable the mathematical curvature checks.

STEP 3

Review the generated engineering data layout. Look for the Summary Box output at the base of your UI:

• PASS / TANGENT: The segment satisfies IRC criteria or is a straight line ($R > 10,000\text{ m}$).
• FAIL: The curve is too sharp for the designated vehicle design speed.

STEP 4

Click the Export PDF Report action button. The application calls an internal cloning window to format a clean, presentation-ready engineering spreadsheet report page directly to an A4 PDF document download.

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Engineered Output Metric Calculations

For every passing node, the tool computes two main structural highway design values:

1. Equilibrium Superelevation ($e$): Calculated using the structural formula: $$e = \frac{V^2}{225 \cdot R}$$ The script automatically caps the output value at a maximum threshold of $7.00\%$ per standard mixed-traffic specifications.

2. Transition Spiral Curve Length ($L_s$): Derived from the comfort rate of acceleration parameters: $$L_s = \frac{0.0215 \cdot V^3}{80 \cdot R}$$ This defines the safe length requirement over which the highway cross-slope shifts from a normal crown to a fully elevated state.

System Engine: Requires the html2pdf dependency library available in your application wrapper template window to build structural report exports.