13. Q. Total reaction time of a driver does not
depend upon
(ESE-2000)
(a) Perception time
(b) Brake reaction time
(c) Condition of mind of the driver
(d) Speed of vehicle
Stopping Sight Distance (SSD)
14. (Multiple select question)
Q. Consider the following factors:
Which of these factors are taken into account for
computing braking distance?
a. Reaction time
b. Speed
c. Coefficient of longitudinal friction
d. Gradient
Stopping Sight Distance (SSD)
15. Stopping Sight Distance (SSD)
Q. Match List –I with List –II and select the correct answer using the
codes given below the lists: (ESE-2011)
List – I List –II
A. Lateral friction 1. Disparity between relevant travel distances
B. Cut-off lagoons 2. Vehicle movement on a curve
C. Skid 3. Summit curves
D. Sight distance 4. Prevention of flooding
Codes:
A B C D A B C D
(a) 2 1 4 3 (b) 3 1 4 2
(c) 2 4 1 3 (d) 3 4 1 2
16. Q. What will be the non-passing sight distance
on a highway for a design speed of 100
kmph when its ascending gradient is 2% ?
Assume coefficient of friction as 0.7 and
brake efficiency as 50%.
(ESE-2015)
(a) 176 m (b) 200 m
(c) 150 m (d) 185 m
Stopping Sight Distance (SSD)
17. Q. Brake is applied on a vehicle which then
skids a distance of 16 m before coming to
stop. If the developed average coefficient of
friction between the tyres and the pavement
is 0.4 then the speed of the vehicle before
skidding have been nearly
(a) 20 kmph (b) 30 kmph
(c) 40 kmph (d) 50 kmph
Stopping Sight Distance (SSD)
18. Q. A vehicle moving at 60 kmph on an
ascending gradient of a highway has to
come to stop position to avoid collision with
a stationary object. The ratio of lag to brake
distance is 6:5. Considering total reaction
time of the driver as 2.5 seconds and the
coefficient of longitudinal friction as 0.36,
the value of ascending gradient (%) is
(a) 3.3 (b) 4.8
(c) 5.3 (d) 6.8
Stopping Sight Distance (SSD)
19. Q. A motorist traveling at 100 km/h on a
highway needs to take the next exit, which
has a speed limit of 50 km/h. The section of
the roadway before the ramp entry has a
downgrade of 3% and coefficient of friction
(f) is 0.35. In order to enter the ramp at the
maximum allowable speed limit the braking
distance (expressed in m) from the exit ramp
is________ (GATE – 16 – Set 2)
Stopping Sight Distance (SSD)
20. Q. While driving at a speed of 30 kmph (with
available friction 0.4) down the grade, the
driver requires a braking distance twice that
required for stopping the vehicle when he
travels up the same grade. The grade is
(a) 7% (b) 10.6%
(c) 13.3% (d) 33.3%
Stopping Sight Distance (SSD)
21. Q. The design speed on a road is 60kmph.
Assuming the driver reaction time of 2.5
seconds and coefficient of friction of
pavement surface as 0.35, the required
stopped distance for two-way traffic on a
single lane road is
(a) 82.1 m (b) 102.4 m
(c) 164.2 m (d) 186.4 m
Stopping Sight Distance (SSD)
22. Stopping Sight Distance (SSD)
Q. If a vehicle travelling at 40 kmph was
stopped with in 1.8 sec after application of
the brakes, then the average skid resistance
coefficient is
(ESE-2014)
(a) 0.63 (b) 0.73
(c) 0.83 (d) 0.93
23. Q. A vehicle was stopped in two seconds by
fully jamming the brakes. The skid marks
measured 9.8 meters. The average skid
resistance coefficient will be
(ESE – 1997)
(a) 0.7 (b) 0.5
(c) 0.4 (d) 0.25
Stopping Sight Distance (SSD)
24. Q. Two cars P and Q are moving in a racing track
continuously for two hours. Assume that no
other vehicles are using the track during this
time. The expressions relating the distance
travelled d(in km) and time t (in hour) for both
the vehicles are given as
P: d = 60 t
Q: d = 60 t2
Within the first one hour, the maximum space
headway would be (GATE – 17 – Set 2)
(a) 15 km at 30 minutes
(b) 15 km at 15 minutes
(c) 30 km at 30 minutes
(d) 30 km at 15 minutes
Stopping Sight Distance (SSD)
31. Defective Vision problems
Eg:
A driver 20/40 vision needs 3 sec to
read a sign posted on a freeway. A
person with 20/20 vision can read
this sign post from a distance of
230m. Show through
Computations whether this driver
has sufficient time to read the sign
driving at a speed of 58kmph. At
what speed would the driver have
to travel just to be able to read the
sign?
32. Defective Vision problems
Eg:
A sign is required to be put up asking drivers to
slow down to 30kmph before entering a zone
y( shown in figure). On this road, vehicles
require 174m to slow down to 30kmph. ( this
distance includes lag and brake distance). The
sign can be read by 6/6 vision drivers from a
distance of 48m. The sign is placed at a
distance of x m from the starting of zone y, so
that even a 6/9 vision driver can slow down to
30kmph before entering zone y. The minimum
value of x in m is
33. General problem of acceleration
Eg:
An impatient driver approaches an
intersection. The through traffic is
quite heavy, with an average gap
of 5 sec. If the driver can achieve
an acceleration of 3 mps2 starting
from rest and his perception
reaction time is 0.75sec.
Determine if he can clear the
intersection? Assume that the
width of intersection is 7.5m and
car length is 6.1m
37. Non-uniform acceleration of vehicles
An impatient car driver stuck behind a slow
moving truck travelling at an initial speed
of 29.33mps decides to overtake the truck.
The acceleration of the car is given by
dv/dt = 3-0.04 v
Where v is the speed in mps, t is time in sec
Determine
a) Acceleration after 120sec
b) Max speed attained by the car
c) How far will the car travel in 120sec
38. Non-uniform acceleration of vehicles
Eg:
The aceeleration time relation for a vehicle subjected to non uniform acceleration is
dv/dt = (α-βvo)e- βt
v is the speed in mps, t time in sec
vo is the initial speed in mps
If the acceleration behavior of a vehicle whose
driver intends to overtake a slow vehicle ahead
is described as, dv/dt= α-βv
Where α= 2 m/s2, β=0.05/s, and dv/dt=1.3m/s2, at t=3 s.
Distance travelled by the vehicle in 35 s is …….
39.
40. Horizontal transition curves
Provided to change the horizontal alignment from
straight to circular curve gradually
The radius changes from infinity to a particular
value or vice versa
41. Transition curve
• Objective
• For the gradual introduction of
Centrifugal force
• To introduce super elevation gradually
• To introduce extra widening gradually
• To provide comfort for the driver that is
to enable smooth vehicle operation on
road.
• To enhance aesthetics of highways.
42. • For single lane roads only mechanical
widening is sufficient
• For two lane roads both mechanical
widening and psychological widening are
reqired
• For roads more than two lanes
pavement widening is calculated by
adding half the widening for two lane
roads for each lane.
Extra widening
44. Extra widening
• Extrawidening is gradually increased on transition curve
• Widening should be applied equally on both sides of the cariageway
45. Extra widening
On curves without transition, widening should be achieved in the same way
of superelevation i.e., two-third being attained on the straight section
before start of the curve and one-third on the curve
