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GATE 2026 CE (CE1) – Question 47

Transportation Infrastructure · Geometric design of roadways: cross-section, sight distance, alignments · 2 marks · Multiple select

Which of the following statements is/are TRUE in the context of the geometric design of highways?

  1. The coefficient of friction used for the design of horizontal curves is lower than the coefficient of friction used in the computation of the sight distances.
  2. Centrifugal force at horizontal curve is counteracted by raising the middle of the pavement with respect to the edges.
  3. Grade compensation is achieved by increasing the gradient of the horizontal curve.
  4. Under identical conditions, the design length of the summit curve of a road having unidirectional flow will be greater than that of the same road having bidirectional flow.

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Correct answer: (A) The coefficient of friction used for the design of horizontal curves is lower than the coefficient of friction used in the computation of the sight distances.

Explanation

The lateral friction for curve design (0.15) is lower than the longitudinal friction used for stopping sight distance (0.35 to 0.40), so A is true. Centrifugal force is counteracted by superelevation, which raises the outer edge, and not by camber, so B is false. Grade compensation reduces the gradient on a curve, so C is false. A road with bidirectional flow needs a longer summit curve because it needs a longer sight distance, so D is false.