It is very normal phenomena, when we take a turn while driving a vehicles, cycling, or even walking, we felt like we are pushed outward. That feeling is due to the effect of centrifugal force, and it becomes even stronger when moving at higher speed or on sharper turn. To counter this force and keep vehicles safely on the road, road being designed is called banking of roads.
What is Banking of Roads?
Banking of roads is the practice of raising the outer edge of a road or track relative to the inner edge on curved sections. Driving on a curved road without banking, we have to rely solely on friction between the tires and the road to prevent the car from skidding off the road. But banking tilts the road, helping vehicles stay on track by providing extra support, so drivers don’t have to rely entirely on friction.
Why Do Roads Need to be Banked?
Friction would be enough to keep a car from sliding off a curved path. However, in reality, friction has its limits. At higher speeds, vehicles experience an outward force (centrifugal force), which can push them off the road if not properly countered. Banking helps to manage :
1.Providing better grip: Incline of the road helps balance the forces acting on the vehicle, allowing it to make a safe turn even at higher speeds.
2. Reducing the reliance on friction: Need for friction to keep the vehicle on the road decreases. Even if the road is slippery due to rain, snow, or oil, banking helps keep vehicles from skidding off.
3. Improving comfort and safety: For drivers, properly banked curves allow for smoother, safer turns without the sensation of the car slipping or tipping over
How Does Banking Work?
When a vehicle takes a turn, two main forces act on it:
1. Centripetal force: This is the inward force needed to keep the vehicle moving in a circular path. It’s directed towards the center of the curve.
2. Centrifugal force: This is the outward force that tries to push the vehicle away from the center of the curve.
For a vehicle to safely steer a curve, the centripetal force needs to counter the centrifugal force. Banking helps in generating the required centripetal force by tilting the road surface. This inclination allows a component of the vehicle’s weight to act as centripetal force, reducing the dependence on friction.
When a road is banked, vehicles experiences two components:
One component acts vertically to balance the weight of the vehicle.
The other component acts horizontally towards the center of the curve, providing the necessary centripetal force.
Angle of banking is carefully calculated based on the speed at which vehicles are expected to move and the radius of the curve
Formula for Banking of Roads
The relationship between the angle of banking (θ), speed (v), radius of the curve (r), and gravitational force (g) is given by the following formula:
tanθ = v2 / rg
Above formula helps in determining the optimal banking angle required for vehicles to safely steer a curve without skidding off the road. Greater the speed or the sharper the curve, the higher the banking angle should be.
Practical Examples of Banking
1.Highways and Freeways: On highways, especially in areas where vehicles travel at high speeds, you’ll notice that the curves are banked. This is done to ensure that even at high speeds, cars can take turns safely without relying heavily on friction.
2. Race Tracks: In motorsports, tracks are often banked at much steeper angles than normal roads. This allows race cars to take turns at very high speeds without losing control.
3. Railway Tracks: Even trains benefit from banking, which is why we see that railway tracks on curves are also raised on one side. This helps reduce wear on the train’s wheels and keeps the train stable at higher speeds.
Banking and Safety
Banking isn’t just about comfort; it’s a crucial safety measure. Without banking, drivers have to reduce their speed considerably while steering curves, especially in bad weather conditions. With banking, even if the friction between the tires and the road decreases due to rain or snow, vehicles can still safely make turns.
.Note:
Banking of roads is an intelligent and essential feature of modern road design that helps vehicles maintain control while turning, particularly at high speeds. By tilting the road, it ensures that vehicles can safely steer curves without skidding off, whether on highways, racetracks, or railway lines, banking plays a critical role in ensuring both the safety and comfort of passengers.
Banking of roads refers to the practice of raising the outer edge of a road or track in comparison to the inner edge on a curved path. This incline helps vehicles take turns safely by providing additional support, reducing the reliance on friction, and ensuring the vehicle doesn’t skid or slide off the road.
Banking is necessary to counteract the centrifugal force experienced by a vehicle when it takes a turn at higher speeds. Without banking, the vehicle might skid outward due to the lack of sufficient friction. Banking helps provide the necessary centripetal force, allowing safer and smoother turns.
Two main forces act on a vehicle when taking a turn on a banked road:
Centripetal force: An inward force required to keep the vehicle moving in a circular path.
Centrifugal force: An outward force that tries to push the vehicle away from the curve.
Banking ensures that a part of the vehicle’s weight helps provide the necessary centripetal force
The angle of banking (θ) is calculated using the formula:
tanθ = v2 / rg
Where:
v = velocity of the vehicle,
r = radius of the curve,
g = acceleration due to gravity.
This formula helps determine the optimal angle of banking for safe navigation of curves at a given speed.
Examples of banking can be seen in:
Highways: Curves are banked to allow vehicles to navigate turns safely at higher speeds.
Race Tracks: Steep banking is used to allow race cars to take turns at very high speeds without losing control.
Railway Tracks: Banking is used on curved sections to maintain the stability of trains and reduce wear on wheels.