Compiled by: Engr Muhammad Abbas Khan

Transportation Engg
1. The sequences of four stage survey in highway alignment is Map Study, reconnaissance, preliminary
survey and detailed survey.
2. The shape of the camber best suited for cement concrete pavement is straight line.
3. For water bound macadam roads in localities of heavy rainfall the recommended value of camber is
1:36.
4. The stopping sight distance depend upon total reaction time of driver, speed of vehicle and
efficiency of brakes.
5. When the path travelled along the road surface is more than the circumferential movement of the
wheel due to rotation then it results skidding.
6. Coefficient of friction is less when the pavement surface is smooth and wet.
7. The shoulder provided along the road edge should be rougher that the traffic lanes.
8. Camber in the road is provided for effective drainage.
9. Compare to a level surface on a descending gradient the stopping sight distance is more.
10. Stopping sight distance: the SSD is the distance accessible along the highway at any given spot and
it enables the driver to slow down the vehicle without a crash. The SSD depend upon total reaction
time of driver, the speed of vehicle, efficiency of the brakes, friction b/w road and vehicle tires and
road gradient.
11. Overtaking sight distance: safe distance that a driver needs to pass a slow moving vehicle by using
road space of the opposite direction of travel.
12. The desirable length of overtaking zone as per IRC recommendation is equal to 5 times the
overtaking sight distance.
13. Stopping sight distance is always less than overtaking sight distance.
14. Intermediate sight distance: double of SSD. Normally required during the night driving conditions.
15. Head light sight distance: the distance which is measured in the direction of vehicle between the
driver position and the far sight object without disturbing the light of sight.
16. For single lane road with way traffic the stopping sight distance is double of SSD (for two lane road
with two-way traffic).
17. Reaction time of a driver decrease with increase in speed.
18. If the stopping distance is x meter than the minimum stopping sight distance is also x meter.
19. The effect of gradient on safe over taking distance is directly proportional. SOT increases with both
descending and ascending.
20. the ruling design speed on national highway in plain terrain as per IRC recommendation is
100KMPH.
21. The terrain may be classified as rolling terrain (vertical and horizontal alignment) if the cross slope
of the land is 10 to 25%.
22. if b is the wheel track of the vehicle and h is the height of center of gravity above road surface then
to avoid overturning and lateral skidding on a horizontal curve the centrifugal ratio should always
be less than b/2h and less than coefficient of lateral friction.
23. Super elevation is method of road construction where the outer edge of the pavement is raised
above the inner edge.
Compiled by: Engr Muhammad Abbas Khan

24. As per IRC recommendation the maximum limit of super elevation for mixed traffic in plain terrain is
1 in 15.
25. for the design of super elevation for mixed traffic condition the speed is reduced by 25%.
26. On a horizontal curve if the pavement is kept horizontal across the alignment than the pressure on
the outer wheel will be more than the pressure on the inner wheel.
V2
27. The equilibrium super elevation required to counteract the centrifugal force fully is given by
127 R
where V is the speed of vehicle in Kmph and R is radius of curve in meter.
28. Friction force develop between contacting surface of two bodies and act to resist the relative
motion between the bodies. Us(Coff of Static Friction)>Uk(Coff of kinematic/sliding friction).
29. for a constant value of coff of lateral friction the value of required super elevation increases with
increase In speed and decrease in radius of curve.
30. The Coefficient of lateral friction as recommended by IRC Is 0.15.
31. To calculate the minimum value of rolling radius of horizontal curve in plains the design speed is
given by 16kmph.
32. The absolute minimum radius of curve for a safe operation of speed 110kpmh is 440m.
33. The attainment of superelevation by rotation of pavement about the inner edge of pavement
avoids the drainage problems in flat terrain.
34. Psychological extra widening depends on the speed of the vehicle.
35. In case of hill road the extra widening is generally provided on the inner sides of the curve.
36. The mechanical extra widening required for 10.5-meter-wide pavement on a horizontal curve of the
3 L2
radius R meter is given by .
2R
37. The transition curve used in the horizontal alignment of highways as per IRC recommendation is
spiral.
38. For design greater length of transition curve should be taken from a. based on allowable rate of
change of centrifugal acceleration b. based on the rate of change of super elevation.
39. The maximum design gradient for vertical profile of road is ruling gradient.
40. Compensation of gradient will only be made if ruling gradient is 1in 20 and horizontal curve radius
curve is <305m.
41. The percentage compensation for ruling gradient of 4% and horizontal curve radius 760 m is zero.
42. If ruling gradient is 1in20 and horizontal curve is 76m<305 then the compensated grade should be
4%.
43. The camber of road should be approximately equal to half of longitudinal gradient.
44. Cubic parabola is preferred in valley curve,
45. the value of ruling gradient as per IRC is 1in30.
Compiled by: Engr Muhammad Abbas Khan

46. In case of summit curve the deviation angle will be max when an ascending gradient meets with a
descending gradient.
47. If the design speed is V and the deviation angle is N radian then the length of the valley curve in
3 1 /2
meter is 0.38(N V ) .
48. If an ascending gradient of 1 in 50 meets with a descending gradient of 1in50 the length of a
summit curve for a stopping sight distance 80m will be 60m.
49. Highway facilities are design for thirtieth highest hourly volume.
50. Endoscope is used to find spot speed.
51. For highway geometric design purpose the speed use is 98 th percentile.
52. Traffic capacity should always be more than the traffic volume.
53. Length of vehicle affect extra width of pavement and minimum turning radius.
54. The maximum width of a vehicle as recommended by IRC is 2.44m.
55. Desire lines are plotted in origin and destination studies.
56. In the desire line diagram width of desire line is proportional to the number of trips in both
directions.
57. Scientific planning of transportation system and mass transit facilities in cities should be based on
origin and destination data.
58. License plate method is preferred for collecting origin and destination data for small area like a
small business center or large intersection.
59. the ruling gradient or the design gradient is the maximum gradient with which the designer attempt
to design the vertical profile of the road.
60. Weaving: vehicle movement cross the path of another along the length of facility without the aid of
traffic signals.

61. Merging: two separate traffic streams join to form a single one.

62. Diverging one traffic stream separates to form two separate traffic streams.
Compiled by: Engr Muhammad Abbas Khan

63. The diagram which shows the approximate path of vehicles and pedestrians involved in accident is
known as collision diagram.
64. Collision diagram is used to study accident pattern and determine remedial measures.
65. The diagram which shows all the important physical condition of an accident location like roadway
limits, bridges and trees and all details of roadway condition is known is condition diagram.
66. With increase with speed of traffic stream the minimum spacing of vehicle increases.
67. Traffic volume = traffic density x traffic speed.
68. Practical capacity is also known as design capacity.
69. If the average c/c spacing of vehicle is 20m than the basic capacity of traffic lane at speed of 50
100× V
kmph is 2500 vehicle/hour. (C=
S ).
70. With increase of maximum speed of traffic, the capacity of lane first increase and then increases
after reaching the maximum value at optimum speed.
71. Equivalent factor of passenger car unit PCU for a passenger per IRC is 1.
72. Density is inversely proportional to the volume of traffic. If the density is less than the speed will be
more and traffic volume will be more.
73. When the speed of traffic flow become zero traffic density attain maximum value whereas traffic
volume become zero.
74. The background color of information sign board is yellow.
75. Level crossing is indicated by a warning sign
76. Dead slow is a regulatory sign
77. The most efficient traffic signal system is flexible progressive system.
78. On a right angled road intersection with two way traffic the total number of conflict point are 24.
79. The provision of traffic signals at intersection reduce right angle collision but may increase rear end
collision.
80. Stop-Red line signals is sum of go and clearance intervals for the cross flow.
81. Clearance time is generally 3 to5 sec
82. The cycle length is normally to 40 to 60 sec for two phase signals.
83. Center line marking are used in roadway meant for two-way traffic.
84. The particular where pedestrian are to the pavement are properly marked by the pavement
marking known as crosswalk lines.
85. The entrance and exit curves of a rotatory have different radia and different width of the pavement.
86. When two equally important roads cross roughly at right angles, the suitable shape of central island
is circular.
87. The maximum number of vehicle beyond which the rotary may not function efficiently is 5000
vehicle per hour.
88. A traffic rotary is justified where number of intersecting roads is 4 to 7.
89. When a number of roads are meeting at a point and only one of the road is important than the
suitable shape of rotary is tangent.
Compiled by: Engr Muhammad Abbas Khan

90. Maximum number of vehicle can be parked with 90 degree.

91. When the width of the kerb parking space and width of the street are limited generally preferred
parking system is parallel parking.
92. As per IRC recommendation the average level of illumination on important roads carrying fast
traffic is 30lux.
93. The most economical lighting layout which is suitable for narrow roads is single side lighting.
94. The direct interchange ramp involves diverging to right side and merging from right.
95. In soil having same plasticity index. If the liquid limit is increased then compressibility, permeability
increases and dry strength decreases.
96. Impact test measure the toughness of road aggregate.
97. If the aggregate impact value is 20-30% then it is classified as satisfactory for road surfacing.
98. Loss angles testing machine is used to conduct abrasion test.
99. The maximum allowable loss angles abrasion value for high surface course is 30%.
loss∈weight∈ grams
100. Coefficient of hardness = ( 20- )
3
101. In CBR test the value of CBR is calculated at both 2.5mm and 5 mm penetration.
102. Percentage of free carbon in bitumen is less than that in tar.
103. The ductility value of bitumen for suitability in road construction should not be less than 50cm.
104. The maximum limit of water absorption for aggregate suitable for road construction is 0.6%.
105. 30/40 represent hardest batch of bitumen.
106. Penetrating test on bitumen is used for determining its grade.
107. Bitumen if 80/100 grade means its penetration value is 8 to 10mm.
108. Bitumen grade 65/25 and 85/40 means softening point and penetration point.
109. The recommended value of tar for grouting purpose is RT-5.
110. Cut back asphalt: the bitumen whose viscosity value will be reduced by addition of volatile
diluents.
111. There are three types of cutbacks a. rapid curing, medium curing and slow curing. RC-2, MC-2
and SC-2 means same viscosity.
112. For rapid curing cutbacks the oil used is gasoline.
113. The method of design of flexible pavement is recommended by IRC is CBR method.
114. Softening point for bitumen to be used for road construction at a place where maximum
temperature is 40C should be greater than 40C.
115. Group index is a number assigned to a soil based on its physical properties like particle size,
plasticity index and liquid limit. Group index method of design of flexible pavement as an empirical
method based on the physical properties of subgrade soil.
116. Minimum and maximum values of group index can be zero and 20 respectively. Values 0-2
indicate good, 2-5 fair, 5-10 poor, 10-20 very poor quality of soil
117. In group index method of flexible design daily volume of commercial vehicle decides the of base
and surface course.
118. In the designing the super elevation of the highway the maximum value is fixed considering the
need to avoid toppling of slow moving vehicle in mix traffic flow.
119. In bituminous pavement alligator cracking is mainly used due to fatigue arising from repeated
stress application.
Compiled by: Engr Muhammad Abbas Khan

120. The purpose of prime coat is to provide bond between existing base and surfacing of new
construction.
121. Penetration test is used for the gradation of asphalt cement.
122. Marshal test is used for the design of bituminous concrete mix.
123.

124. Road CS of flexible pavement consist of from bottom to top, Subgrade, sub base, base course,
blinder surface and surface course. Prime coat is between blinder coat and base coat. While tack
course is applied between surface course and binder course. Seal coat is most of the top coat.
125. Flexible pavement distributes the wheel load through a set of layers to the subgrade.
126. The difference between the rigid and flexible pavement is based on the manner in which the
loads are distributed to the subgrade.
127. Load carrying capacity of rigid pavement depend upon properties of concrete than strength of
subgrade.
128. Compared to flexible pavement the rigid pavements are more effected by temperature
variation.
129. For design flexible pavement by CBR method as per IRC the load parameter required is
cumulative standard axle in msa.
130. Critical load position in a rigid pavement design is taken as interior, edge and corner loading.
131. The number of repetition which the pavement thickness designed for a given wheel load should
be able to support throughout the life is 1 million.
132. Tire pressure influences the quality of surface coarse.
133. Rigidity factor for a tyre pressure greater than 7 kg/cm2 is less than 1.
134. In a dual wheel assembly if P is equal to each wheel load, S is c/c distance of each wheel load
and d is the distance between walls of wheels then total stress due to dual wheels at any depth
greater than 2S is equivalent to a single wheel load of magnitude 2P.
135. Main drawback of CBR method is that it gives the total thickness which remains the same
irrespective of the quality of materials used in the component of layers.
136. When the radius of wheel load distribution is more than 1.725 times of slab thickness, hence
radius of resistance thickness is equal to the radius of load wheel distribution.
137. The critical combination of stresses for a corner region in cement concrete road is load stress+
warping stress.
Compiled by: Engr Muhammad Abbas Khan

138. Tie Bars in cement concrete pavement are longitudinal joints.

139. The maximum spacing of expansion joints in rigid pavement is 25mm.
140. Expansion joints in cement concrete pavement are provided at interval of 18m to 21m.
141. Contraction joints are spaced lowered than expansion joints.
142. In the design of highways expansion and contraction joints are provided at 50m and 10m.
143. Longitudinal joints are provided in cement concrete road to prevent longitudinal cracking.
144. Warping joints are provided to relieve stresses induce due to warping.
145. The function of an expansion joint in rigid pavement is to allow free expansion.
146. The fundamental factor in the selection of type of pavement is type and intensity of traffic.
147. Most suitable materials for highway embankment is granular soil.
148. Maximum daily traffic capacity of bituminous pavement is 1500 tons per day.
149. The most suitable equipment for compacting claying soil is sheep foot roller.
150. The binder normally used in flexible pavement construction is bitumen.
151. In highway construction rolling starts for sides and proceeds to center.
152. On highway construction on super elevated curves the rolling shall proceed from lower edge
towards the upper edge.
153. For the construction of water bound macadam roads the correct sequence of operation after
spreading coarse aggregate. Dry rolling –application of screening-wet rolling and application of
filler.
154. In the penetration macadam construction, the bitumen is sprayed after the aggregate are
spread and compacted.
155. When the bituminous surface is done on already existing black top of road or existing cement
concrete road the type of treatment is known as tack coating.
156. Bituminous bound macadam is used for base coarse.
157. A bitumen primer is a high viscosity cutback.
158. The suitable surfacing materials for a bridge deck slab is mastic asphalt.
159. Bituminous concrete is considered to be the highest quality construction in the group of black
top pavement.
160. The thickness of bituminous carpet varies from 20 t0 25mm.
161. Reflection cracking is observed in bituminous overlay over cement concrete surface.
162. Sheet asphalt is a carpet of sand bitumen mix without coarse aggregate.
163. A hill road is one which passes through a terrain of 25-60% of cross slope.
164. In hill road if several alternate alignments are surveyed which fulfill the geometric requirement
then alignment with minimum resisting length should be selected.
165. The camber for hill road in case of bituminous surface is 2.5%.
166. The drain provided parallel to the roadway to intercept and divert the water from hill slope call
catch water drain.
167. The wall on the hill side of the road where earth is to retained from slipping is known as breast
wall.
168. In hill roads the sides drain is provided only on the hill side of the road.
169. Emulsion is used for stabilizing the desert sand.
170. Soil lime stabilization is very effective for stabilizing back cotton soil.
171. Soil lime stabilization is very effective in warm region.
172. Emulsion is recommended for wet and cold climate.
Compiled by: Engr Muhammad Abbas Khan

173. Soil bitumen stabilization is the most common method for stabilization.
174. The minimum design speed for hairpin bends in hill road is taken as 20%.
175. The proportioning of materials determined from laboratory test for bituminous or asphalt
concrete.
176. Requirement of maximum tractive effort for a short distance Is associated with limiting gradient
on highways.
177. Hairpin bends in hill road construction does not help in the prevention of landslides in moon
soon season.
178. In loss angles test if the speed of the drum is increased by 50rpm then the abrasion value
increases.
179. Low bitumen content causes raveling in bituminous pavement.
180. Marshal diagram is drawn between flow value (y) and % binder content by weight of total mix
on x.
181. A rotatory will be more suitable than control by signal in case of traffic volume entering from all
roads is less than 3000 vehicles per hour and total right turning traffic is high.
182. Soundness: disintegration of concrete due to weathering.
183. Abrasion: the removal of material from the surface of road by grinding action.
184. Attrition: Mutual rubbing or grinding within the mass under the pressure of traffic.
185. Crazing: breaking up of road surface layer through cracking into irregular shape areas.
186. Ratio of width of parking car area required at kerb for 30’ parking relative to 60’ parking is
aprrox 0.5.
187. In down grade of the highway an emergency escape ramp is provided.
188. The plasticity index of pattern passing 425 microns IS sieve in case of sub base or base course is
less than 6.
189. If the CBR value obtained at 5mm penetration >than at 2.5 mm and also for second time then
take higher CBR value at 5mm.
190. Chronological sequence of road construction is –Tresaguet, Telford, Macadam and CBR.
191. The general requirement in constructing a reinforced concrete road is to place a single layer of
reinforcement near the top of the slab.
192. It is a common practice to design a highway to accommodate the traffic volume corresponding
to 30th hour.
193. For the design of valley vertical curves, the criteria considered rider comfort, head light sight
distance and drainage.
194. Pavement deficiency (Bird Bath): deformation which may be caused by localized or variable
subgrade failures.
195. Pot Holes: a steep sided bowl-shaped cavity caused by the loss of surfacing and as well as base
coarse erosion.
196. Ravelling: Removal of larger surface aggregate leaving craters.
197. Subsidence: abrupt lowering of road surface due to poor drainage.
198. For carrying out bituminous patch work during the rainy season the most suitable binder is
bituminous emulsion.
199. Intermediate site distance as per IRC id 2SSD (stopping site distance)
200. to determine the moisture correction factor of claying sub grade soil in bankleman beam the
important factors are Annual average rainfall and temperature of soil.
Compiled by: Engr Muhammad Abbas Khan

201. rapid curing cutback bitumen is produced by blending bitumen with petrol
202. Medium curing cutback bitumen is produced by blending bitumen with kerosene.