REPORTER
NO.
5:
FAILURES,
MAINTENANCE,
REHABILITATION OF TRANSPORTATION INFRASTRUCTURES
AND
RAILWAY FAILURE:
1. Rail wear
2. Rolling Contact Fatigue (RCF)
01: TRANSPORT INFRASTRUCTURES
Transport infrastructure refers to the framework that supports
transport system.
02: FAILURES IN TRANSPORT SYSTEM
Failures in transport infrastructure refer to a breakdown,
malfunction, or inadequacy in the functioning or performance
of various components or systems within the transport network.
A.
B.
C.
Poor Highway and Road Conditions – often caused
by inadequate maintenance and funding, pose
safety risks and lead to traffic congestion, costing
drivers time and money while undermining overall
transportation efficiency.
Bridge Failure – Design error, construction mistakes,
hydraulic, collision, and overload are the top 5
leading causes of bridge failures, resulting in more
than 70% of the bridge failures. Causes of bridge
failures are closely related to regional economy,
structural type, type of use, material type, and service
age.
Railway Failure
03: MAINTENANCE
Maintenance in transport infrastructure refers to the ongoing
activities and processes aimed at preserving, repairing, and
improving the condition and performance of various
components and systems within the transport network.
Cracks
Potholes
Raveling
FAILURES THAT OCCUR IN LAYERS OF PAVEMENT:
1.
2.
3.
4.
Subgrade Failure – subbase = natural soil; causes:
weak subgrade soil, poor drainage or prolonged
exposure to water (should not be too dry nor too
wet), inadequate compaction during construction.
Subbase Failure
Base Course Failure – causes: insufficient thickness,
poor material quality, environmental factors (freezethaw cycles and moisture infiltration can weaken the
base course)
Surface Course Failure – causes: poor mix design,
inadequate thickness, poor material quality
Traffic engineering is a branch of civil engineering that focuses
on the planning, design, and management of traffic and
transportation systems.
TRAFFIC CHARACTERISTICS:
1.
MAINTENANCE ON DIFFERENT TRANSPORT INFRASTRUCTURE:
1.
2.
3.
COMMON SIGNS OF ROAD AND HIGHWAY FAILURES:
1.
2.
3.
REPORTER NO. 6: TRAFFIC ENGINEERING
Roads/Highways Maintenance – involves activities
like filling potholes, repaving worn-out sections,
repairing road signs, and ensuring proper drainage.
Regular maintenance helps keep roads safe, smooth,
and efficient for drivers.
Railway Maintenance – Involves the regular upkeep,
repair, and improvement of various components that
make up a railway system.
Bridge Maintenance – Includes work such as repairing
damage or deterioration in various bridge
components; removing debris and drift from piers,
bearing seats, abutments, etc.; cleaning out drains;
repairing expansion joints; cleaning and painting
structural.
04: REHABILITATION
Rehabilitation addresses the need to substantially improve the
failing features of a building, mainly involving the repair or
restoration (through strengthening or replacement) of the
structure in a way that ‘returns its performance to levels
approaching or exceeding those of a newly constructed
facility.
STEPS OF REHABILITATION:
1.
2.
3.
4.
5.
6.
7.
8.
Assessment and Inspection
Data Collection and Analysis
Condition Evaluation
Defining Rehabilitation Objectives
Development of Rehabilitation Strategies
Design and Engineering
Cost Estimation and Budgeting
Environmental and Social Impact Assessment
2.
3.
Density and Occupancy

Density – refers to the number of vehicles per unit
length of road

Occupancy – is the percentage of time a
detector senses a vehicle
Speed and Volume
Traffic Flow – refers to the movement of vehicles
along a road network over a specific period of time
FACTORS AFFECTING TRAFFIC FLOW
o
o
o
o
Driver behavior
Road capacity
Traffic signal timings
Weather conditions
IMPORTANCE OF SPEED AND VOLUME STUDIES
o
o
o
Design speed limits
Helps determine road safety
Plan for traffic control devices
TRAFFIC STUDIES
1.
2.
3.
4.
5.
Accident Studies – analyze historical accident data
to identify high-risk areas and implement safety
improvements
Origin-Destination Studies – track the movement of
vehicles between different origins and destinations
within a city or region
Parking Studies – assess the demand for parking
spaces in specific areas to plan for adequate parking
infrastructure
Speed Studies – evaluate the speed of vehicles on a
specific roadway segment to assess compliance with
speed limits and identify potential safety concerns
Volume Studies – measure the number of vehicles
passing a specific point on a roadway to assess traffic
demand and capacity
TECHNIQUES FOR ACCIDENT STUDIES DATA COLLECTION



On-site investigation
Police reports
Traffic camera footage
1.
2.
TECHNIQUES FOR PARKING DATA COLLECTION





3.
License plate tracking system
Parking lot counts
Surveys
TECHNIQUES
FOR
DATA
DESTINATION STUDIES)
COLLECTION
(ORIGIN-
GPS tracking
License plate recognition technology
Radar gun
GPS-based Speed Tracking Device
Speed camera
1.
2.
3.

Road capacity – maximum number of vehicles that can pass a
specific point on a road during a given time period
FACTORS AFFECTING ROAD CAPACITY
Number of lanes
Presence of intersections
Road width
Traffic signal timings
METHODS FOR CALCULATING ROAD CAPACITY
o
o
o
Empirical models
Simulation software
Traffic flow analysis
Highway capacity – Highways are designed for high-speed,
long-distance travel with limited access points
TRAFFIC OPERATIONS REGULATIONS AND CONTROLS
Traffic Operations – involve the day-to-day management and
control of traffic flow on roadways. It encompasses various
strategies and measures to ensure safe, efficient, and smooth
traffic movement
Traffic Signals – regulate the right way at intersections
Stop Signs – require drivers to come to a complete
stop
Yield Signs – indicate that drivers must yield the right
of way.
DESIGN OF AT-GRADE INTERSECTIONS – At-grade intersections
are intersections where roadways meet at the same level. They
are common in urban areas and can take various forms
CAPACITY OF URBAN ROADS AND HIGHWAYS
o
o
o
o
Speed Limits – set appropriate speed limits based on
road conditions and traffic flow
Lane management – designate lanes for specific
uses, such as carpool lanes or bus-only lanes
Traffic signage – ensure clear and visible signage to
guide drivers and pedestrians
TRAFFIC CONTROL DEVICES
TECHNIQUES FOR SPEED MEASUREMENT:



TECHNIQUES OF TRAFFIC REGULATION:
DESIGN CONSIDERATIONS:
a. Lane configuration – determine the number of
lanes in each direction.
b. Traffic signal placement – position signals for
optimal visibility and control
c. Pedestrian crosswalks – ensure safe pedestrian
crossings
DESIGN OF GRADE-SEPARATED INTERSECTIONS
1.
2.
3.
REPORTER NO. 7: TRAFFIC FLOW AND ANALYSIS OF ROADS
INCLUDING QUEUING ANALYSIS AND LEVEL OF SERVICE
ANALYSIS
01: TRAFFIC FLOW THEORY
Traffic flow theory – involves the development of mathematical
relationships among the primary elements of a traffic stream:
flow,
density,
and
speed.
– used in design to determine adequate lane lengths for storing
left turn vehicles
02: TIME-SPACE DIAGRAM
Time-space diagram serves as a useful device for defining the
elements of traffic flow. This is a graph that describes the
relationship between the location of vehicles in a traffic stream
and the time as the vehicles progress along the highway.
03: PRIMARY ELEMENTS OF TRAFFIC FLOW
PRIMARY ELEMENTS OF TRAFFIC FLOW:
1.
2.
3.
BENEFITS:
4.
Cost – this is a challenge; Grade-separated
intersections can be expensive to construct
Improved safety – Reduces the risk of accidents at
intersections.
Reduced congestion – Eliminates the need for traffic
signals, allowing for continuous flow.
5.
6.
7.
Flow (q) – is the equivalent hourly rate at which
vehicles pass a point on a highway during a time
period less than 1 hour
Density (k) – sometimes referred to as concentration,
is the number of vehicles traveling over a unit length
of highway at an instant in time.
Speed (u) – is the distance traveled by a vehicle
during a unit of time
Time Headway (h) – is the difference between the
time the front of a vehicle arrives at a point on the
highway and the time the front of the next vehicle
arrives at that same point.
Space Headway (d) – is the distance between the
front of a vehicle and the front of the following
vehicle and is usually expressed in feet.
Time Mean Speed (ūt) is the arithmetic mean of the
speeds of vehicles passing a point on a highway
during an interval of time.
Space Mean Headway (ūs) – is the harmonic mean of
the speeds of vehicles passing a point on a highway
during an interval of time.
04: FUNDAMENTALS DIAGRAM OF TRAFFIC FLOW
Fundamental diagram of traffic flow – is the relationship
between the density (veh/mi) and the corresponding flow of
traffic on a highway.
a.
b.
c.
Flow vs. Density
Space Mean Speed vs. Density
Space Mean Speed vs. Volume
Jam density (𝑘�𝑗�) – when density reaches its maximum
05: MODELS OF TRAFFIC FLOW
MODEL OF TRAFFIC FLOW:
1.
Poisson Model – models that account for the nonuniformity of flow are derived by assuming that the
pattern of vehicle arrivals (at a specified point)
corresponds to some random process.

Limitations of the Poisson Model – The primary
limitation of the Poisson model of vehicle arrivals
is the constraint imposed by the Poisson
distribution that the mean of period observations
equals the variance.
06: QUEUING ANALYSIS
Queuing is the study of traffic behavior near a certain section
where demand exceeds available capacity.
In transportation engineering, queueing can occur at red
lights, stop signs, bottlenecks, or any design based or trafficbased flow constriction. When not dealt with properly, queues
can result in severe network congestion or “gridlock”
conditions, therefore making them something important to be
studied and understood by engineers.
1.
2.
3.
4.
“Gawker” Effect
Accidents and Incidents
At-Grade Crossing with other Modes
Geometric Bottlenecks
Inclement Weather
Ramp Meters
Toll Booths
Traffic Signals and Intersection Controls
07: CAPACITY AND LEVEL OF ASSESSMENT
Capacity analysis involves the quantitative evaluation of the
capability of a road section to carry traffic, and it uses a set of
procedures to determine the maximum flow of traffic that a
given section of highway will carry under prevailing roadway
traffic and control conditions.
Level of Service (LOS) – measure of the quality of flow, a
qualitative measure, ranging from A to F.
PROCEDURES FOR DETERMINING THE LOS ON TWO-LANE
HIGHWAYS:
1.
2.
3.
4.
5.
Two Levels of Analysis: Operational Applications &
Planning Applications
Highway Capacity Manual (HCM) Procedure
Two Measures Used to Describe the Service Quality of
a Two-Line Highway: PTSF & ATS
Base Conditions – It is the absence of restrictive
geometric, traffic, or environmental factors.
Level of Service
TWO LEVELS OF ANALYSIS:
Operational Applications – specific roadway characteristics;
future traffic conditions, and existing traffic conditions.
Planning Applications – use estimates and default value in
calculations

Cumulative Input-Output Diagram (Newell Curve)
Uncapacitated queues (M/D/1) and (M/M/1)
M/M/N Queuing
Real Life Causes of Queue Generation
REAL LIFE CAUSES OF QUEUE GENERATION (FOR ROADS):
a.
b.
c.
d.
e.
f.
g.
h.
Two classes of two-lane highways:
1. Class 1: Primary arterials, daily commuter
routes, and links to other arterial highways.
Travel will be at relatively high speeds.
2. Class 2: Travel speeds will be lower than for
Class I roads.
TWO MEASURES USED TO DESCRIBE THE SERVICE QUALITY OF A
TWO-LINE HIGHWAY:
1.
Percent-Time Spent Following another vehicle – is the
average percentage of time that vehicles are
traveling behind slower vehicles.
2.
Average Travel Speed – is the space mean speed of
vehicles in the traffic stream. This is a measure of the
degree of providing efficient mobility.
BASE
CONDITIONS
CHARACTERISTICS:
a.
b.
c.
d.
e.
f.
g.
h.
EXIST
FOR
THE
FOLLOWING
Clear shoulders 1.8m wide or greater
Control or turning vehicles
Equal volume in both directions (for analysis of twoway flow)
Lane widths 3.6m or greater
Level terrain
No impediments to through traffic due to traffic
Passenger cars only in the traffic stream
Passing permitted with absence of no-passing zones
Capacity of a two-lane highway is 1700 passenger cars per
hour (pc/h) for each direction of travel and is nearly
independent of the directional distribution of traffic.
REPORTER NO. 8: PAVEMENT MATERIAL & DESIGN
3.
Pavement material design refers to the process of selecting,
specifying, and designing the materials that make up the
various layers of a road pavement.
The Indian Roads Congress (IRC) provides guidelines and
specifications for pavement design in India.
4.
MAIN COMPONENTS:
1.
2.
3.
4.
Subgrade – the natural soil or prepared foundation
on which the pavement is constructed.
Base Course – the layer placed directly above the
subgrade, which provides additional support and
stability to the pavement.
Sub-base Course – is added between the base
course and subgrade to improve drainage and load
distribution.
Surface Course – top layer of the pavement that
comes into direct contact with traffic
KEY STEPS:
1.
2.
3.
Material Selection – choosing appropriate materials
for each layer based on factors such as traffic load,
climate, and local availability
Material Specifications – defining the specific
properties and characteristics that these materials
must meet to ensure the desired pavement
performance.
Material Testing – conducting laboratory and field
tests to assess the properties of the chosen materials.
FACTORS:
1.
2.
CLIMATE AND ENVIRONMENTAL CONDITIONS – Local
climate factors, such as temperature extremes,
rainfall, and freeze-thaw cycles, can affect the
choice of materials and the design of drainage
systems. Environmental conditions, such as soil
moisture and the presence of corrosive chemicals,
also play a role.
DESIGN LIFE – The expected service life of the
pavement is a critical factor. Pavements are
designed to last for a specific period, and the design
must consider factors that can impact longevity,
including traffic growth and maintenance plans
5.
6.
7.
GEOMETRIC DESIGN – the alignment, cross-section,
and lane width of the roadway are crucial for safety
and functionality. Proper geometric design ensures
that the pavement can accommodate the intended
traffic flow.
MATERIAL PROPERTIES – the properties of the materials
used in the pavement, including their strength,
durability,
and
thermal
characteristics,
are
fundamental to the design.
PAVEMENT STRUCTURE – the number and thickness of
pavement layers, such as subgrade, sub-base, base,
and surface courses, are determined based on
factors like traffic loads, material properties, and soil
conditions
SUBGRADE STRENGTH AND SOIL PROPERTIES – The
quality and strength of the subgrade soil beneath the
pavement are essential. Soil tests and evaluations are
performed to determine the subgrade's bearing
capacity and its ability to support the pavement
structure
TRAFFIC LOAD AND VOLUME – The type, volume, and
weight of traffic that the pavement will be subjected
to have a significant impact on the pavement's
design. This includes the number of vehicles, their axle
loads, and their distribution across the road.
FLEXIBLE PAVEMENT DESIGN (AS PER IRCC)
a.
b.
c.
Design Method: IRC recommends the use of the
California Bearing Ratio (CBR) method or the Indian
Roads Congress method for flexible pavement
design.
Layer Composition: Flexible pavements typically
consist of multiple layers, including the subgrade, subbase, base course, and wearing course.
Thickness Design: Thickness design involves
determining the appropriate thickness of each layer
to withstand traffic loads while ensuring adequate
service life
RIGID PAVEMENT DESIGN (AS PER IRC)
a.
b.
Design Method: IRC recommends the use of the
Westergaard' s Theory for the design of rigid
pavements
Slab Thickness: Rigid pavements are designed as a
series of slabs, and the thickness and spacing of these
c.
slabs are determined to distribute the loads
effectively.
Joint Spacing: The spacing of joints, such as
expansion and contraction joints, is critical for
controlling cracking in rigid pavements