Cant Deficiency around a Curve

Cant Deficiency is the difference between the actual superelevation provided and the recommended superelevation for a particular curve radius and speed. When a vehicle travels around a curve, it experiences a lateral acceleration that is perpendicular to the direction of motion. To counteract this lateral acceleration, the roadway is banked or superelevated to provide a centripetal force to the vehicle.

Equilibrium Speed

The equilibrium speed is the speed at which the lateral acceleration experienced by the vehicle is equal to the centripetal force provided by the superelevation. At this speed, the vehicle can safely negotiate the curve without experiencing any skidding or rollover.

Speeds Higher than Equilibrium Speed

If the vehicle travels at speeds higher than the equilibrium speed, the lateral acceleration experienced by the vehicle exceeds the centripetal force provided by the superelevation. This results in the vehicle skidding or rolling over, which can lead to accidents. In this case, the cant deficiency occurs as the vehicle requires additional banking to safely negotiate the curve.

Speeds Lower than Equilibrium Speed

If the vehicle travels at speeds lower than the equilibrium speed, the lateral acceleration experienced by the vehicle is less than the centripetal force provided by the superelevation. This results in the vehicle sliding towards the inner edge of the curve, which can also lead to accidents. In this case, the cant deficiency occurs as the superelevation is excessive for the given speed.

Booked Speed

The booked speed is the maximum speed at which a vehicle can safely travel around a curve, considering the design parameters such as curve radius, superelevation, and gradient. If the vehicle exceeds the booked speed, the cant deficiency occurs, which can result in accidents.

Conclusion

In conclusion, cant deficiency occurs when a vehicle travels around a curve at speeds higher than the equilibrium speed. It is important to design the roadway with the appropriate superelevation for the given curve radius and booked speed to ensure safe driving conditions.

Check centripetal and centrifugal force and balancing of a vehicle on a curved road.