Engineering Tools
Calculators
12 PE-verified tools covering transportation, drainage, pavement, and earthwork.
Stopping Sight Distance
AASHTO-based stopping sight distance calculator for level and graded roadways using design speed, grade, and perception-reaction time.
Open Calculator → TransportationHorizontal Curve Design
Horizontal curve calculator — tangent length, arc length, external distance, middle ordinate, and long chord from radius or degree of curve.
Open Calculator → TransportationVertical Curve Design
Vertical curve calculator for crest and sag geometry — K-value, PVC/PVT station and elevation, and high/low point.
Open Calculator → Grading & SiteworkEarthwork Volume
Earthwork volume calculator using the average end area method for cut/fill volume from cross-section data, with BCY and LCY output.
Open Calculator → DrainageManning's Equation / Pipe Flow
Manning's equation calculator for full-pipe capacity and velocity using Manning's n — solve for discharge or back-solve for slope.
Open Calculator → PavementAASHTO Pavement Design
AASHTO 1993 flexible pavement design calculator — structural number from ESALs, reliability, DPSI, and subgrade resilient modulus.
Open Calculator → Traffic EngineeringSignal Timing (HCM)
HCM signal timing calculator — Webster's optimal cycle length, phase splits, and critical v/c ratio for 2–4 phases.
Open Calculator → Drainage & HydrologyRational Method — Peak Runoff
Rational Method peak runoff calculator (Q = CiA) for drainage areas up to 200 acres, with composite C from multiple land use types.
Open Calculator → Drainage & HydrologyTime of Concentration
Time of concentration calculator using the Kirpich formula and the TR-55 three-segment method (sheet, shallow concentrated, channel flow).
Open Calculator → TransportationPassing Sight Distance
AASHTO four-component passing sight distance calculator for two-lane highways, computing d₁ through d₄ with speed-interpolated parameters.
Open Calculator → TransportationCurve Superelevation
Curve superelevation calculator — required superelevation rate, minimum radius, and runoff length for horizontal curves per the AASHTO e+f method.
Open Calculator → DrainageCulvert Sizing
Culvert sizing calculator — minimum culvert diameter from Manning's equation given design discharge and slope, with standard pipe size selection and velocity check.
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