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Overturning of vehicles on a curve can be avoided by using
Transition
Compound
Reverse
All of these
Transition
Overturning of vehicles on a horizontal curve can be effectively avoided by introducing a transition curve. Transition curves allow the gradual introduction of superelevation (cant) and centrifugal force, preventing sudden lateral shocks and instability. This gradual change in lateral acceleration ensures that the destabilizing overturning moment is smoothly counterbalanced.
Overturning of vehicles on a horizontal curve can be effectively avoided by introducing a transition curve. Transition curves allow the gradual introduction of superelevation (cant) and centrifugal force, preventing sudden lateral shocks and instability. This gradual change in lateral acceleration ensures that the destabilizing overturning moment is smoothly counterbalanced.
WPтАЛ=gRv2тАЛ тАФ Centrifugal ratio acting on a vehicle moving on a curve
WPтАЛ=2hbтАЛ тАФ Condition for critical overturning, where b is track width and h is height of C.G.
When a vehicle negotiates a curve, centrifugal force acts horizontally outwards through its center of gravity, creating an overturning moment. By employing a transition curve with superelevation gradual buildup, the outer edge of the pavement is slowly raised, creating an inward inclined plane that reduces the net overturning moment.
A transition curve provides a smooth transition from a straight section (radius = тИЮ) to a circular curve (radius = R).
It helps in gradual application of superelevation and extra widening of the carriageway.
Overturning is avoided when the centrifugal ratio WPтАЛ is less than 2hbтАЛ.
Gradual introduction of centrifugal force avoids sudden jolts to passengers.
Enables smooth transition of superelevation, preventing vehicle overturn or lateral skid.
Improves driver comfort, aesthetic appearance, and overall safety on roads and railways.
Requires additional land width and precise surveying work during alignment setting.
Increases design complexity and construction effort compared to simple circular curves.
Highways and expressways at horizontal curve junctions to maintain design speeds safely.
Railway tracks at curve approaches to allow smooth cant transition and prevent derailment.
Option B (Compound Curve) consists of two or more circular curves of different radii turning in the same direction, which does not inherently eliminate sudden lateral shock unless paired with transitions.
Option C (Reverse Curve) consists of two circular curves turning in opposite directions, creating high instability and overturning risk if transition curves are not provided.
A is correct тАФ Transition curves gradually introduce superelevation and centrifugal force, mitigating sudden overturning moments on vehicles.
Always remember the two stability criteria on curves: for overturning, check WPтАЛ<2hbтАЛ, and for skidding, check WPтАЛ<f (coefficient of lateral friction).