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As per IRC, Super elevation(e) should not exceed
70%
70%
15%
35%
70%
According to the Indian Roads Congress (IRC:73-1980), the maximum super elevation on plain and rolling terrain is capped at 7% (often represented as 0.07 or 7%). However, when considering the transition to lower speeds or specific urban conditions, 6.70% (or 1 in 15) is a standard limit used in professional design calculations to balance comfort and safety.
According to the Indian Roads Congress (IRC:73-1980), the maximum super elevation on plain and rolling terrain is capped at 7% (often represented as 0.07 or 7%). However, when considering the transition to lower speeds or specific urban conditions, 6.70% (or 1 in 15) is a standard limit used in professional design calculations to balance comfort and safety.
e+f=gRv2тАЛ тАФ Fundamental equation for design of super elevation where f is lateral friction and R is radius.
emaxтАЛ=0.07 тАФ Maximum super elevation permitted by IRC for plain and rolling terrain.
Super elevation (e) is provided to counteract the centrifugal force acting on a vehicle moving on a curve. The design is governed by the equilibrium of lateral forces, where e+f=gRv2тАЛ. IRC mandates a maximum cap to prevent vehicles from sliding inward when standing still on icy or slippery surfaces, especially at lower design speeds.
Super elevation is the inward transverse slope provided on a horizontal curve.
It counteracts the outward centrifugal force.
For hilly terrain, the maximum super elevation can go up to 10%.
In urban areas, the value is restricted to 4% due to frequent intersections and drainage concerns.
Reduces the risk of skidding for vehicles moving at design speed.
Promotes uniform distribution of wheel loads on the pavement.
Enhances comfort by counteracting centrifugal effects.
Can be problematic for slow-moving vehicles on icy roads.
Complicates drainage design at the inner edge of the curve.
Highways (NH/SH)
Expressways
Transition segments of railway tracks
The value 6.7% is derived from the geometric design standard of 1 in 15.
Options C and D (0.15% and 0.35%) are extremely low and impractical for highway geometry.
B is correct тАФ As per IRC guidelines, the maximum super elevation on plain and rolling terrain is limited to 7%, with 6.7% (1 in 15) being a standard design specification.
Remember that for hilly terrain, the max super elevation is 10%, while in urban areas it is limited to 4% due to cross-drainage requirements.