Superelevation Calculator
Calculate highway curve superelevation rate, bank angle, minimum curve radius, and maximum safe speed using AASHTO design formulas.
Inputs
mph
ft
AASHTO Table 3-7: 20 mph f=0.18; 40 mph f=0.15; 60 mph f=0.12; 80 mph f=0.08
Results
Superelevation Rate (e)
0 ft/ft
Min Radius (e_max=8%)
614 ft
Superelevation0%
Bank Angle0°
Max Speed for Radius57.4 mph
How to Use This Calculator
- Enter design speed and horizontal curve radius.
- Set maximum superelevation rate per your jurisdiction (AASHTO typically 4–8%).
- Review required superelevation (e) and transition length.
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