Highway Engineering Multiple Choice Questions on “Sight Distance”.
1. The length visible to driver at any instance of time is called ___________
a) Sight distance
b) Visibility limit
c) Head light distance
d) Overtaking sight distance
Answer: a
Clarification: The length of the road that is visible to the driver at any time is called sight distance, in night visibility it is headlight sight distance and in zone which it can be overtaken is called overtaking sight distance.
2. The stopping sight distance of a vehicle moving with 45kmph and having a coefficient of friction as 0.4 is?
a) 48m
b) 49m
c) 50m
d) 51m
Answer: d
Clarification: SSD=0.278vt+v2/254f
SSD=0.278*45*2.5+452/(254*0.4)
SSD=51m.
3. The stopping sight distance does not depend on ___________
a) Break reaction time
b) Speed of vehicle
c) Length of vehicle
d) Friction
Answer: c
Clarification: SSD=0.278vt+v2/ (254f)
In this equation t is the reaction time taken by driver for stopping the vehicle, v is the speed of the vehicle and f is the coefficient of friction, so the SSD is independent of the length of the vehicle.
4. The SSD is based on ___________
a) Speed of vehicle
b) PIEV theory
c) Voluntary action of brain
d) Reflex action of brain
Answer: b
Clarification: The SSD is based on PIEV theory, it is the theory that estimates the time taken to perceive and react.
5. The reaction time considered in SSD is ___________
a) 1.5 sec
b) 2 sec
c) 2.5 sec
d) 3 sec
Answer: c
Clarification: The reaction time considered in SSD unless and until specified is 2.5 sec; it is based on PIEV theory.
6. The desirable relationship between OSD and length of overtaking zone is ___________
a) Length of overtaking zone = OSD
b) Length of overtaking zone = 2 OSD
c) Length of overtaking zone = 3 OSD
d) Length of overtaking zone = 5 OSD
Answer: d
Clarification: The minimum length of the overtaking zone is 3 times of OSD, but desirable is 5 times of OSD.
7. If the speed of overtaken vehicle is 80Kmph, then the design speed is ___________
a) 80kmph
b) 96kmph
c) 100kmph
d) 106kmph
Answer: c
Clarification: Vb=V-16
V=Vb+16
V=80+16=96Kmph.
8. If the speed of overtaken vehicle is 50kmph then spacing of vehicles is ___________
a) 10m
b) 12m
c) 14m
d) 16m
Answer: d
Clarification: The spacing of vehicles is given by S=0.2Vb+6
S=0.2*50+6
S=16m.
9. The reaction time of a driver assumed in OSD is ___________
a) 1 sec
b) 2 sec
c) 2.5sec
d) 3 sec
Answer: b
Clarification: The reaction time assumed is 2 sec which is less than time taken in SSD because here the driver does not need to perceive and react so this time is less than the time taken in SSD.
10. The height of the driver above the road level is assumed as ___________
a) 1.1m
b) 1.2 m
c) 1.5 m
d) 1.6m
Answer: b
Clarification: The height of the driver assumed is 1.2m which is till the eye level; this is assumed for clear vision in night.
11. The relationship between SSD and ISD is?
a) SSD = ISD
b) SSD = 1.5 SSD
c) SSD = ISD + OSD
d) SSD = 2 ISD
Answer: d
Clarification: The ISD is the intermediate sight distance which is provided when there is no possibility of providing OSD as far as possible the roads are provided with SSD = 2 ISD relationship.
12. The sight distance recommended by IRC for 50kmph speed is?
a) 100m
b) 110m
c) 120m
d) 200m
Answer: b
Clarification: IRC recommends a sight distance of 110m for a speed of 50kmph, 180m for a speed of 80kmph and 220m for a speed of 100kmph.