Highway Engineering Questions and Answers - Design of Vertical Alignment

1. The vertical alignment of a highway includes?
a) Sight distance and traffic intersection
b) Widening of pavements
c) Design of valley curves and gradients
d) Highway lighting

Explanation: The design of valley curves, summit curves and gradient are included in the vertical alignment of highway.

2. The ruling gradient required for plain or rolling terrain is ___________
a) 1 in 15
b) 1 in 20
c) 1 in 30
d) 1 in 40

Explanation: The ruling gradient value required for plain and rolling terrain type of road is 1 in 30 or 3.3%.

3. The maximum grade compensation for a curve of radius 75m is?
a) 1%
b) 1.4%
c) 1.5%
d) 1.6%

Explanation: The maximum grade compensation is 75/R = 75/75 = 1%.

4. The vertical alignment does not influence?
a) Sight distance
b) Vehicle operation cost
c) Accidents
d) Vehicle speed

Explanation: The vertical alignment influences sight distance, vehicle operation cost, vehicle speed and comfort while travelling at high speed.

5.The angle which is measured at the change of direction of two gradients is called ___________
a) Standard angle
b) Subtended angle
c) Deviation angle
d) Setback angle

Explanation: The angle which denotes the direction of change of two gradients angle is called as deviation angle.

6. The length of the summit curve is based on ___________
a) Comfort
b) Sight distance
c) Convexity
d) Deviation angle

Explanation: The length of summit curve is based on stopping sight distance, it is further divided into two cases when L>SSD and L<SSD.

7. The value of “a” in the equation y=ax2 used in the summit curve is ___________
a) N/2L
b) N/3L
c) N/4L
d) N/5L

Explanation: The value of the constant “a” is N/2L where N is the deviation angle and L is the length of the curve.

8. If the length of the summit curve having SSD as 150m and deviation angle is 1 in 30 is ___________
a) 50m
b) 100m
c) 150m
d) 170m

Explanation: The length of the summit curve is given by
L=NS2/4.4
L=1*150*150/ (4.4*30)
L=170m.

9. If the deviation angle of the curve is 1/200 and the design speed is 80kmph then calculate the total length of the valley curve for comfort condition.
a) 18.22
b) 18.52
c) 19.22m
d) 19.52m