Transportation Lecture 2.pdf

1
Spring 2023 (4th Semester)
Dr. Bakht Zamin
(bakht@cecos.edu.pk)
Department of Civil Engineering
CECOS University Peshawar

Lecture Outlines
❑ Transportation Planning – Introduction
❑ Basic Elements of Transportation Planning
❑ Transportation Planning Institutions
❑ Transportation Planning Organizations
❑ Travel Surveys and Travel Demand
❑ Travel Forecasting and Travel Forecasting Model
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Transportation Planning
❑ Transportation Planning is the process of defining
future policies, goals, investments and designs to
fulfill the future needs and demands in most
effective and well organized way.
❑ Transportation planning is highly essential in
shaping cities, enabling economic activities,
promoting community interaction and enhancing
quality of life.
❑ It is also essential for sustainable development and
ensuring safe accessibility at various levels for all
individuals.
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❑ The transportation planner begins by
❑ Defining the problem
❑ Gathering and analyzing data
❑ Evaluating various alternative solutions
❑ Transportation planning process also involve
❑ Forecast of future traffic
❑ Estimates of the impact of facility on land use
❑ The environment
❑ The community
❑ Cost – benefits analysis
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❑ Among the factors that may justify a transportation
project are
❑ Improvements in traffic flow and safety
❑ Energy consumption
❑ Travel time
❑ Economic growth
❑ Accessibility
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❑ Some transportation projects may have been
selected for reasons unrelated to specific benefits
❑ To stimulate employment in a particular region.
❑ To compete with other cities or statesfor prestige.
❑ To attract industry.
❑ To respond to pressures from a political constituency.
❑ To gain personnel benefits from a particular project.
❑ Whatever the reason for selecting or rejecting a
transportation project, a specific process led to the
conclusion to build or not to build.
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Basic Elements of Transportation Planning
❑ The transportation planning process comprises
seven basic elements, which are interrelated and
not necessarily carried out sequentially.
❑ The information acquired in one phase of the
process may be helpful in some earlier or later
phase.
❑ So there is a continuity of effort that should
eventually result in a decision.
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❑ The elements of transportation planning are:
❑ Situation definition
❑ Problem situation
❑ Search for solutions
❑ Analysis of performance
❑ Evaluation of alternatives
❑ Choice of project
❑ Specification and construction.
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Situation Definition
❑ Understanding of situation that give rise to the
perceived need for a transportation improvement is
required
❑ In this phase, the present system is analyzed and its
characteristics are described
❑ Information about the surrounding area, its people
and their travel habits may be obtained
❑ Previous reports and studies that may be relevant to
the present situation are reviewed and summarized
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Problem Definition
❑ The purpose of this step is to describe the problem
in terms of objectives to be accomplished by the
project and to translate those objectives into
criteria that can be quantified.
❑ Objectives are statement of purpose, such as to
reduce traffic congestion, to improve safety, to
reduce noise etc.
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Problem Definition
❑ Criteria are the measure of effectiveness that can be
used to quantify the extent to which a proposed
transportation project will achieve the stated
objectives.
❑ For example, the objective “to reduce traffic
congestion” might use “travel time” as the measure
of the effectiveness.
❑ The characteristics of an acceptable system should
be identified and specific limitations and
requirements should be noted.
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Search Solution
❑ In this phase of planning process, consideration is
given to a number/variety of ideas, designs,
locations and system configurations that might
provide solutions to the problem.
❑ This is the brainstorming stage, in which many
options may be proposed for later testing and
evaluation.
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Search Solution
❑ Alternatives can be proposed by any group or
organization.
❑ This phase also includes preliminary feasibility
studies, which might narrow the range of choices.
❑ Some data gathering, filed testing and cost
estimation may be necessary at this stage to
determine the practicality and financial feasibility of
the alternatives being proposed
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Analysis of Performance
❑ The purpose of performance analysis is to estimate
how each of the proposed alternatives would
perform under present and future conditions.
❑ The criteria identified in the previous steps are
calculated for each transportation option.
❑ This step is a determination of the investment cost
of building the transportation project, as well as
annual costs for maintenance and operation.
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Analysis of Performance
❑ It also include the use of mathematical models for
estimating travel demands.
❑ The number of persons/vehicles that will use the
system is determined and are considered in design
process.
❑ Environmental effects of the transportation project
are also estimated.
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Evaluation of Alternatives
❑ The purpose of the evaluation phase is to
determine, how well each alternative will achieve
the objectives of the project as defined by the
criteria.
❑ The performance data produced in the analysis
phase are used to compute the benefits and costs
that will result if the project is selected.
❑ In cases where the results cannot be reduced to a
single monetary value, a weighted rating for each
alternative might be produced and compared with
other proposed projects.
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Choice of Project
❑ Project selection is made after considering all the
factors involved.
❑ In a simple situation, for example, where the
projects has been authorized and is in the design
phase, a single criteria might be used and the
chosen project might be the one with the lowest
cost.
❑ With a more complex project, many factors have to
be considered, and selection is based on how the
results are perceived by those involved in decision
making.
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Choice of Project
❑ If the project involves the community, it may be
necessary to hold additional public hearings.
❑ It is possible that none of the alternative will meet
the criteria and hence additional investigation will
be necessary.
18

Specification and Construction
❑ This phase involves the physical location, geometric
dimensions and structural configurations of a
project.
❑ Design planes are produced that can be used by
contractors to estimate the construction cost of
building the project.
❑ When a construction firm is selected, these planes
will be the basis on which the project will be built.
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Transportation Planning Organization
Policy Committee
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Policy Committee
❑ The policy committee is composed of elected or
appointed officials such as the director of public
works, who represent the governing bodies or
agencies that will be affected by the results.
❑ This committee makes the basic policy decisions
and acts as board of directors for the study.
❑ Committee members will decide the management
aspects of the study as well as key issues of a
financial or political nature.
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Technical Committee
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Technical Committee
❑ The technical committee is composed of the
engineering and planning staffs that are responsible
for carrying out works or evaluating the technical
aspects of the project prepared by consultants.
❑ This group will assure that the necessary
evaluations and cost comparisons for each project
alternative are complete and will supervise the
technical details of the entire process.
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Technical Committee
❑ Typically, the technical committee will include
❑ Highway and traffic engineers
❑ Specialists in land use planning
❑ Economists
❑ Environmental engineers
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Citizen Advisory Committee
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❑ The citizen advisory committee is composed of a
cross section of the community and may include
representatives from labor and business interested
citizens and members of community interest groups
❑ The committee’s functions are
❑ To express community goals and objectives
❑ To suggest alternatives
❑ To react to the proposed alternatives
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❑ Through this committee structure, an open dialogue
is facilitated among the policy makers, technical
staff and community.
❑ When a selection is made and recommendations
are produced by the study, they should be based on
the consensus of all interested parties.
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Assignment #1
• Demonstrate the sustainable Transportation
System.
• Explain their salient Features.
• Give few examples of such system currently
operating in Pakistan with the technical
specification.
• SubmissionDate: 11th April, 2023
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Quiz # 1
• Quiz no. 1 will held in Next Class.
• Topic: Lectures 1 & 2
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Link, Node and Centroid
❑ A highway network consists of links, nodes and
centroids
❑ Link is a portion of the highway system that can be
described by its capacity, lane width and speed
❑ Node is the end point of the link and represents an
intersection or location, where a link changes
direction , capacity, width or speed
❑ Centroid is the location within a zone where trips
are considered to began and end
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Travel Surveys
❑ Travel surveys are conducted to establish a
complete understanding of the travel patterns
within the study area
❑ For single projects (e.g. highway project), it may be
sufficient to use traffic counts on existing roads or
counting of passengers riding the present system
❑ To understand why people travel or where they
wish to go, Origin – Destination (O – D) survey data
can be useful
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Travel Surveys
❑ The O – D survey asks questions about
❑ Where the trips begins and ends
❑ The purpose of the trip
❑ The time of the day
❑ The type of the vehicle involved
❑ The type of person making the trip
❑ The O – D survey may be completed by asking
questions the people while riding the bus or when
stopped at a roadside interview station
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Travel Demand
❑ Travel demand is expressed as the number of
persons or vehicles per unit time that can be
expected to travel on a given segment of a
transportation system
❑ The factors that influence the demand for travelling
are
❑ The location and intensity of land use
❑ The socioeconomic characteristics of people
living in the area
❑ The extent, cost and quality of available
transportation services
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Factors Influencing Travel Demand
❑ Land use characteristics are a primary determinant
of travel demand
❑ The amount of traffic generated by a parcel of land
depends on how the land is used
❑ For example
❑ Shopping centers
❑ Residential complexes
❑ Office buildings
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❑ Socioeconomic characteristics of the people living
within the society also influence the demand for
transportation
❑ Life styles and values affect how people decide to
use their resources for transportation
❑ For example, a residential area consisting primarily
of high income workers will generate more trips per
person than a residential area populated primarily
by retirees
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❑ Availability of transportation facilities and services
also affects the demand for travel
❑ Travelers are sensitive to the level of services
provided by alternative transportation modes
❑ Choosing mode of transportation depends on
attributes such as
❑ Travel time
❑ Cost
❑ Convenience
❑ Comfort
❑ Safety
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Travel Forecasting
❑ Travel forecasting is the attempt of estimating the
number of vehicles or people that will use a specific
transportation facility in the future
❑ Travel forecasting begins with the collection of
current traffic data
❑ This traffic data is combined with the other known
data such as population, employment, travel cost
etc. to develop a traffic demand model for the
current situation
❑ Feeding it with the predicted data for population,
employment etc. results in the estimate of future
traffic
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Travel Forecasting
❑ Travel forecasts are used for several key purposes in
transportation policy, planning and engineering to
calculate the capacity of infrastructure
❑ For example
❑ How many lanes a bridge should have
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Four-Step Model For Travel Forecasting
❑ Travel forecasting follows the sequential four-step
model or urban transportation planning procedure
❑ The four step of the classical urban transportation
planning system model are:
❑ Trip generation
❑ Trip distribution
❑ Mode choice
❑ Route/ network assignment
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Trip Generation – How many trips are generated
❑ Trip generation is the process of determining the
number of trips that will begin or end in each traffic
zone
❑ The number of trips produced by and attracted to
each zone depends on its
❑ Residential characteristics
❑ Employment characteristics
❑ Industrial characteristics
❑ For example, the more employment a zone has, the
more work trips it attracts
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Trip Distribution – Where do trips go
❑ Trip distribution is a process by which the trips
generated in one zone are allocated to other zones
in the study area
❑ Trips end are linked to create complete trips
❑ These trips may be within the same zone (internal-
internal) or between adjacent zones (internal-
external) with varying distance
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Mode Choice – What travel mode is used for each trip
❑ Mode choice predicts the choices that
individuals or groups make in selecting their
transportation modes
❑ An important objective is to predict the share
of trips attracted to public transportation
❑ Other factors considered for mode choice
include travel time, travel cost etc.,
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Route/Network Assignment – What is the route of
each trip
❑ The final step is to determine the routes travelers
choose to reach their destinations
❑ Route/Network assignment requires the following
❑ Number of trips that will be made from one zone to
another zone
❑ A description of highway routes between zones
❑ Travel time on each zone route segment
❑ External trips that were not considered in previous steps
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