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Introduction to
Transportation Engineering
CIE 128 : Principles of Transportation
Engineering
Lesson Objectives
At the end of this lesson, you will be able to:
1. Explain the role of Transportation Engineering in improving transportation systems.
2. List and describe the various modes of transportation and their characteristics
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Transportation Engineering
Transportation Engineering is a branch of Civil Engineering that is
involved in the planning, design, operation, and maintenance of safe
and efficient transportation systems. Transportation engineers are
required to possess a long-term vision of the future. They must remain
steadfast, patient, and persistent in guiding a transportation project to
completion. The transportation engineer works in an environment
where change is gradual and sometimes imperceptible.
Transportation Engineering
Transportation ensures time and place utility. It results in the
movement of goods from one place to another place thus making
the product available through the customer at the right time. To develop
the economy of certain nation, good transportation is one of the key
elements. Without good transportation, a nation or region cannot
achieve the maximum use of its natural resources or the maximum
productivity of its people.
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Transportation Engineering
Progress in transportation is not without its costs, both in human lives
and environmental damage, and it is the responsibility of the
transportation engineer working with the public to develop high quality
transportation consistent with available funds and social policy and to
minimize damage.
Different Modes of Transportation
An essential part of transportation management lies in building an efficient supply chain from the six main
modes of transportation: road, maritime, air, rail, and pipeline. Understanding the strengths and
weaknesses of each mode is paramount to building an effective supply chain.
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Road Transportation
A road is an identifiable route way or
path between two or more places. This
mode of transport helps to transfer
the goods from one place to another
place by road through various
methods like auto, buses, trucks,
cargos, and other suitable factors. In
road transport, the chances of an
accident are very high and it is also
very risky.
Railways Transportation
It is preferred due to high speed.
Invariance to road transport, where
vehicles run on a flat road or surface, rail
vehicles are directionally managed by the
rail tracks on which they run. Within the
confines of the railway system, the rail
vehicle is not influenced by traffic, points
of diversion, and switch offs between
modes. This makes the rail the most
dependable mode for making long hauls
across land with minimal damage. Trains
commonly carry bulk cargo items such as
coal, corn, iron, ore, and wheat, items that
would be uneconomical to ship by truck.
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Maritime Transportation
It involves the movement of goods
through oceans and seas. Cargo ships
travel on almost every major body of
water and have capacity to transport the
highest volume of freight of any mode of
transportation at the lowest cost. The
greatest disadvantage of maritime cargo
ships is the speed at which they operate.
By far, maritime is the slowest mode of
transportation. Additionally, the carbon
emissions produced by one cargo ship
are equivalent to the emissions
produced by 50 million cars.
Air Transportation
Airplanes are becoming increasingly
important in domestic and
international trade. As air travel has
become increasingly advanced and
dependable, more companies are
trusting airplanes with high value
freight and goods. The increasing
popularity of flight as a preferred
way to travel also makes shipping by
air more convenient as shipments
regularly piggyback on passenger
planes, further making air an
economic way to transport goods.
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Pipelines
Pipeline shipping is not a formal mode of
transportation in the traditional sense.
However, it is important to acknowledge
for its importance in the current fossil fuel
market. Pipe-lines are the specialized
means of transportation designed to move
the items like crude-oil, petroleum,
chemicals, coal, lime-stone, iron ore,
copper concentrates
And gas.
Intermodal Transportation (Multimodal)
Intermodalism concerns a variety of modes
used in combination so that the respective
advantages of each mode are advantaged.
Although intermodal transportation applies to
passenger movements, such as using the
different, interconnected modes of a public
transit system, it is over freight transportation
that the most significant impacts of
intermodalism have been observed.
Containerization has been a powerful vector
of intermodal integration, enabling maritime
and land transportation systems to
interconnect
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Transportation Impact
Lecture 1
SIGHT DISTANCE ON
HORIZONTAL SURFACE
CIE 128 : Principles of Transportation
Engineering
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Lesson Objectives
At the end of this lesson, you will be able to:
1. Explain the importance of stopping sight distance in highway design.
2. Calculate reaction distance and braking distance as components of stopping sight
distance.
3. Evaluate the necessary stopping sight distance for highway design.
Stopping sight distance on horizontal surface
Sight Distance – is the length of roadway visible to the driver.
Stopping Sight Distance (SSD) – is the minimum sight distance available on a highway at
any spot having sufficient length to enable the driver to stop a vehicle traveling at design speed,
safely without collision with any other obstruction.
Factors affecting Stopping Sight Distance (SSD):
Total reaction time of driver
Speed of vehicle
Efficiency of Brakes
Frictional resistance between road and tire.
Gradient of road
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Stopping sight distance on horizontal surface
Total reaction time of driver:
- It is the time taken from the instant the object is visible to the driver to the instant the
brake is effectively applied; it divided into two types:
1. Perception Reaction Time
- It is the time from the instant the object comes on the line of sight of the driver to
the instant he realizes that the vehicle needs to be stopped.
2. Brake Reaction Time
- The brake reaction depends on several factor including the skill of the driver, the
type of the problems and various other environment factor.
PIEV Theory was proposed to provide detailed account of driver's reaction. PIEV is the
amount of time it takes a driver to react to a hazard.
Stopping sight distance on horizontal surface
Total reaction time of driver is split into four parts:
1. Perception
- Is the time required for the sensations received by the eyes or ears of the
driver to be transmitted to the brain through the nervous system and spinal cord
or it is the time required to perceive an object or situation.
2. Intellection
- Is the time required for the driver to understand the situation, it is also the time
required for comparing the different thoughts.
3. Emotion
- Is the time elapsed during emotional sensational and other mental disturbance
such as fear, anger or any other emotional feeling superstition.
4. Volition
- Is the time taken by the driver for the final action such as brake application.
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Stopping sight distance on horizontal surface
Reaction Distance
The distance a vehicle travels from
the moment a driver sees the object
until the driver applies brakes.
Braking Distance
The distance a vehicle travels from the
moment the brakes are applied until
the vehicle come to a complete stop.
Note: Usually, 2.5 seconds is used as
Brake Reaction Time or Perception-
Reaction Time.
G is positive for uphill slope, and
negative for downhill slope.
Stopping sight distance on horizontal surface
Rectilinear Translation Formulas
A. Uniform Motion (Constant Velocity)
𝑠 = 𝑣𝑡
B. Variable acceleration
𝑎= 𝑣= 𝑣𝑑𝑣 = 𝑎𝑑𝑠
C. Constant Accelation
𝑣 = 𝑣 + 𝑎𝑡 𝑠 = 𝑣 𝑡 + 𝑎𝑡 𝑣 = 𝑣 + 2 𝑎𝑠
𝑣 − 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑎𝑡 𝑎𝑛𝑦 𝑡𝑖𝑚𝑒, 𝑡
𝑣 − 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦
𝑎 − 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛
𝑠 − 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒
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Sample problem 1
Compute the braking distance, stopping sight distance and intermediate
sight distance for a car moving at an initial velocity of 60 kph and a final
velocity of 40 kph.
Slope of roadway is +5%
Coefficient of friction between road pavement and tires = 0.15
Perception – reaction time is = 0.75 sec.
Sample Problem 2
The driver of a vehicle travelling at 80 kph up a grade requires 9 m. less
to stop after applies the brakes than the driver traveling at the same
initial speed down the same grade. If the coefficient of friction between
the tires and pavement is 0.50, what is the percent grade and what is
the breaking distance down the grade.
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Sample Problem 3
Compute the intermediate sight distance for a free way with a design
speed of 80 kph if the perception time is assumed to be 2.5 seconds
with a skid resistance of 0.70. Assume brake efficiency to be 60%. (hint:
Intermediate sight distance is 2x the SSD)
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