253. Curves in the same direction separated by short tangents, are called

A. simple circular curves

B. compound curves

C. transition curves

D. broken-back curves.

254. The minimum ratio of the radii of two circular curves of a compound curve, is kept

A.1.25

B.1.5

C.1.75

D. 2.0.

255. The minimum superelevation in rolling terrain in plains, is limited to

A.4%

B.5%

C.6%

D.7%

256. If the designed speed on a circular curve of radius 1400 m is 80 km/hour, no superelevation is provided, if the camber, is

A.4%

B.3%

C.2%

D. 1.7%.

257. If N is deviation angle, the length L of a parabolic vertical curve for safe stopping distance S, is

A. NS2 if L > S

B. 25 ? ?N tf L < S

C. VS2 if L < S

D. 25 if L > S

258. If N is deviation angle the length L of a parabolic vetical curve for overtaking sight distance S, is

A. ?9.6 if L > S

B. 2S ?if L < S

C. 2IS if L < S

D. both (a) and (b).

259. The safe length L of a valley curve for night travel is

A.1.50 + 0.035S

B.0 + 0.035S

C. neither (a) nor (b)

D. both (a) and (c).

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