1 questions with worked solutions.
Q1. A two lane, one-way road with radius of 50 m is predominantly carrying lorries with wheelbase of 5 m. The speed of lorries is restricted to be between 60 kmph and 80 kmph. The mechanical widening and psychological widening required at 60 kmph are designated as wme,60 and wps,60 respectively. The mechanical widening and psychological widening required at 80 kmph are designated as wme,80 and wps,80 respectively. The correct values of wme,60, wps,60, wme,80, wps,80 are
- (A) 0.89 m, 0.50 m, 1.19 m, and 0.50 m
- (B) 0.50 m, 0.89 m, 0.50 m, and 1.19 m
- (C) 0.50 m, 1.19 m, 0.50 m, and 0.89 m
- (D) 1.19 m, 0.50 m, 0.89 m, and 0.50 m
Answer: (B) 0.50 m, 0.89 m, 0.50 m, and 1.19 m
Mechanical widening Wme = n*l^2/(2R) = 2*25/100 = 0.50 m at both speeds (independent of speed). Psychological widening Wps = V/(9.5*sqrt(R)) gives 0.89 m at 60 kmph and 1.19 m at 80 kmph. So the set is 0.50, 0.89, 0.50, 1.19 (option B).