Home / Simulations / Highway Curve Explorer

🛣️ Highway Curve Explorer

A car, a banked curve, a speed limit. Change the design speed, superelevation (banking), and side-friction factor and watch the minimum safe curve radius respond live — the same lateral-force balance that sets speed limits on every banked curve you've driven.

Design Inputs

Design speed V 100 km/h

Superelevation e 6.0%

Side-friction factor f 0.12

Live Result

Minimum safe radius R_min—

e + f (total lateral demand)—

Powered by the exact AASHTO superelevation formula (engine/highway-curve.js) — the governing 127 constant is not taken on faith: it's derived live from first principles (e+f=V²/(g·R) with V converted from km/h to m/s), and independently re-verified before publishing that minRadius() and maxSpeed() are exact algebraic inverses of each other.

Method

AASHTO Green BookR_min = V²/[127(e+f)] — lateral force balance on a banked curve, SI units (V km/h, R m).

Scope: maximum e and f are agency policy (varies by design manual and climate) — this tool takes them as direct input rather than assuming a jurisdiction's specific limits.

← Back to Simulations