Road Gradient Calculator
Calculate road gradient (slope) as a percentage and angle from the rise and run distance.
Gradient
5.00 %
Gradient vs Vertical Rise
Formule
## Road Gradient Calculation Gradient expresses how steep a road is. ### Formulas **Gradient (%) = (Rise / Run) x 100** **Slope ratio = 1 in (Run / Rise)** (e.g., 1 in 20) **Slope distance = sqrt(Rise^2 + Run^2)** Design guidelines typically limit residential roads to 8-12% and highways to 3-6% depending on terrain and design speed.
Exemple Résolu
A road rises 5 m over a horizontal distance of 100 m.
- 01Gradient = 5/100 x 100 = 5%
- 02Slope ratio = 1 in 100/5 = 1 in 20
- 03Slope distance = sqrt(25 + 10000) = sqrt(10025) = 100.12 m
Questions Fréquentes
What is the maximum gradient for roads?
Flat terrain highways: 3-4%. Rolling terrain: 5-6%. Mountainous: 6-8%. Residential streets: up to 12%. Pedestrian ramps (ADA): 8.33% maximum (1:12). Parking ramps: up to 15%.
How does gradient affect vehicles?
On steep upgrades, heavy trucks lose speed significantly. A 2% grade reduces truck speed by about 10 km/h over 1 km. Steep downgrades require sustained braking, risking brake fade. Climbing lanes are added when trucks slow more than 15 km/h below design speed.
What is super-elevation?
Super-elevation is the banking (cross-slope) of a road on curves to counteract centrifugal force. Maximum super-elevation is typically 8-12%. It is separate from longitudinal gradient.
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