lecture 2
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LECTURE 2
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Agenda
Road planning and route outline
Transport demand
Definition, mobility and accessibility Road hierarchy and function
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HIGHWAY PROJECT APPRAISAL
5 themes: economy safety
environmental impact
accessibility
integration
Economic or investment appraisal provides a framework
for rational decisions on the use of limited resources:
2 broad approaches
Cost benefit (or Social Welfare) analysis
Impact statement approach
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HIGHWAY PROJECT APPRAISAL
APPRAISAL SUMMARY TABLE
Scheme Name: Length: Cost:
All-weather route between X and Y AADT: z veh/day
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5
1.Problem Identification
2. Pre feasibility study(initial identification of solutions)
3.Feasibility study/ Preliminary Engineering design (screening of solutions to preferred option)
4. Final Engineering Design( Specifying the preferred option for bidding)
5. Procurement and negotiation(pre- construction)
6. Implementation/ Construction
7. Operation
8. Monitoring and evaluating
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New construction
Upgrading
Rehabilitation
Stage construction
Maintenance
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The road sector faces huge challenges including ambitious demands such as better, quicker and cheaper production, construction and maintenance.
Road Project Appraisal/ Assessment- Overseas Road Note 5
It provides a guidance on carrying out feasibility studies for road projects in developing countries.
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The ORN 5 consists of 4 parts
Part 1
Part 2
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Part 3
Part 4
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Appraisal Criteria
Economic Impacts:
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Economic analysis of road projects Economic feasibility studies of road projects are used to provide guidance to planners and engineers on transport investment. In addition to helping in taking the decision whether or not to build a road between A and B, they can also address questions such as:
How cost effective is a project? How does one choose between alternative projects?
Which is the best route?
What is the most appropriate design standard?
When should work begin?
Should there be stage construction?
NOT ALL THE CONSEQUENCES OF AN INVESTMENT CAN BE
QUANTIFIED IN ECONOMIC TERMS.
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Appraisal Criteria:
Environment:
Noise & vibration noise level Global air quality carbon dioxide Local air quality NOx , CO Water Water quality/ Drainage/ Flood
defense Landscape Geological features
Ecological features Visual impacts Agriculture Heritage Landscape character
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Appraisal Criteria:
Accessibility:
Integration
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ROAD INVESTMENT MODEL
Calculates the construction cost of a road
Predicts the condition of the road wrt loading & time
Estimates costs of road maintenance and cost of operation of vehicles for each year
Costs discounted back to the base year and summed over the life of the road to obtain the total cost
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ROAD INVESTMENT MODEL- uses
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ROAD PROJECT
Feasibility stage
Objectives
Background
Institutional & managerial aspects
Traffic
Design
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ROAD PROJECT
Define Objectives Determine alternative ways of meeting objectives Preliminary considerations Assessing traffic demand Design and cost different options: Determine benefits for each alternative Economic analysis and comparison of Alternative Cost Benefit analysis Recommendation- Presentation of feasibility Report
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ROAD PROJECT
Appraisal Criteria- ORN 5
Main criteria to consider:
Technical
Financial
Economy
Safety
Environment impact
Accessibility
Integration
Sustainability and risks
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ROAD PROJECT
ASSESSMENT OF BENEFITS
Vehicle operating cost savings
Time savings
Reduction in road accidents
Economic development benefits
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ROAD PROJECT
Feasibility report Summary and conclusions Brief description of project
Objectives Project type Main features Preliminary considerations
Assessment of demand Determining costs Assessment of benefits Economic analysis Financial aspects Other aspects Implementation Plans for monitoring and evaluation
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ROAD PROJECT
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Transport demand is directly related to land use patterns and to the available transportation systems and facilities.
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Transport
demand
Landuse Transport
facilities
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Stages in the development of a road network:
In the light of experience from the developed countries, there would seem to be
three distinct stages in the development of a road network:
1. Initially it is necessary to establish a road network to at least provide a basic means
of communication between centers of population. At this stage little attention is paid
to geometric standards as it is much more important to consider whether a road link
exists at all or, if it does, whether it is passable at all times. 2. The next stage is to build capacity into the road network. Geometric standards
probably have little to contribute to this except in the areas of road width and
gradient. Much more important factors are whether or not a road is paved, or whether
it has sufficient structural strength to carry the traffic wishing to use it.
3. The final stage is to consider operational efficiency of the traffic using the network
and it is at this time that geometric standards become really important.
The designer is faced with the challenge to try and make roads safe no matter which
of these stages of development a road system has reached.
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Traffic engineers/ planners attempt to provide capacity for observed or predicted travel demand by either building new transportation systems or upgrading existing transportation systems.
The improvement of existing transport systems, makes the adjacent and nearby lands more accessible, hence, more accessible.
Building new transportation facilities leads to further increases in landuse development, which in turn results in higher transportation demands.
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Building or upgrading works will either enhance mobility or accessibility or both.
Mobility- Refers to the ability to travel to many destinations.
Accessibility- Refers to the ability to gain entry to a particular site/ area.
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The proximity of a land to a major highway and public transportation facilities is a major factor in determining its value.
A good transportation system must provide for both mobility and accessibility and should be designed to separate both functions to the extent possible to ensure both safety and efficiency.
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Highways systems- mobility is provided by facilities such as freeways, expressways, primary and secondary arterials.
Accessibility is provided by local street networks, which serve only through vehicles (mobility).
Most classes of highway serve both functions to some degree.
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Road hierarchy and function-
ORN 6
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Road hierarchy and function
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Road hierarchy and function
Access Roads
Access roads are the lowest level in the network
hierarchy. Vehicular flows will be very light and will be
aggregated in the Collector road network. Geometric
standards may be low and need only be sufficient to provide
appropriate access to the rural agricultural, commercial and
population centres served. Substantial proportions of the total
movements are likely to be by non-motorised traffic.
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Road hierarchy and function
Collector Roads
Collector roads have the function of linking traffic to
and front rural areas, either direct to adjacent urban centres, or
to the Arterial road network. Traffic flows and trip lengths
will be of an intermediate level and the need for high
geometric standards is therefore less important.
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Road hierarchy and function
Arterial Roads
Arterial roads are the main routes connecting national
and international centres. Traffic on them is derived from
that generated at the urban centres and from the inter-
urban areas through the Collector and Access road
systems. Trip lengths are likely to be relatively long and
levels of traffic flow and speeds relatively high.
Geometric standards need to be adequate to enable
efficient traffic operation under these conditions, in
which vehicle-to-vehicle interactions may be high.
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