Traffic & Highway Engineering - الصفحات...
Transcript of Traffic & Highway Engineering - الصفحات...
Traffic & Highway Engineering
Text Book
Fourth Edition, SI
Nicholas J. Garber
Lester A. Hoel
2010
Transportation Systems
and Organizations
Chapter 2
Transportation System & Organization
Developing a Transportation System
Modes of Transportation
Transportation Organization
Chapter 2
Chapter 2 Transportation
Systems and Organizations
SUMMARY
The transportation system in a developed nation
consists of a network of modes that have evolved
over many years.
The system consists of vehicles, guide ways,
terminal facilities, and control systems;
these operate according to established
procedures and schedules in the air, on land, and
on water.
The system also requires interaction with the user,
the operator, and the environment.
Chapter 2 Transportation
Systems and Organizations
SUMMARY
The passenger or shipper thinks of each mode in
terms of the level of service provided.
Each mode offers a unique set of service
characteristics at a given price: travel time,
frequency, comfort, convenience, reliability, and
safety.
The traveler or shipper selects the mode based on
how these attributes are valued.
Chapter 2 Transportation
Systems and Organizations
2.1.1 Comparative Advantages of
Transportation Modes
Students are requested to read this topic
and to discuss it in the next lecture
Chapter 2 Transportation
Systems and Organizations
Example 2.1 Selecting a Transportation Mode (p29)
An individual is planning to take a trip between
the downtown area of two cities, A and B,
which are 400 km apart.
There are three options available:
Travel by air. This trip will involve driving to
the airport near city A, parking, waiting at the
terminal, flying to airport B, walking to a taxi
stand, and taking a taxi to the final destination.
Chapter 2 Transportation
Systems and Organizations
Example 2.1 Selecting a Transportation Mode (continued)
Travel by auto. This trip will involve driving
400 km through several congested areas,
parking in the downtown area, and walking to
the final destination.
Travel by rail. This trip will involve taking a
cab to the railroad station in city A, a direct rail
connection to the downtown area in city B, and
a short walk to the final destination.
Chapter 2 Transportation
Systems and Organizations
Example 2.1 Selecting a Transportation Mode (continued)
It is a business trip
The traveler is willing to pay $25 for each hour of
travel time reduced
Mode cost $ time (hours)
Air 250 5
Auto 200 8
Rail 150 12
Which mode is selected based on travel time and
cost factors alone?
What other factors might be considered?
Solution:
Since travel time is valued at $25/hr, the following costs would be incurred:
Air: 250 + 25(5) = $375
Auto: 200 + 25(8) = $400
Rail: 150 + 25(12) = $450
In this instance, the air alternate reflects the lowest cost and is the selected mode.
Other factors:
Safety, reliability and convenience.
Chapter 2 Transportation
Systems and Organizations
Chapter 2 Transportation
Systems and Organizations
2.2 MODES OF TRANSPORTATION
2.2.1 Freight and Passenger Traffic
Intercity freight transportation
Principal mode:
Highways (truck)
Railroads
Water
pipelines
Chapter 2 Transportation
Systems and Organizations
2.2 MODES OF TRANSPORTATION
Intercity passenger transportation
Principal mode:
Highways (automobile)
Air
Transit (bus)
Railroads
Chapter 2 Transportation
Systems and Organizations
SUMMARY
The evolved transportation system has produced
a variety of modes that complement each other.
Intercity passenger travel often involves auto and
air modes;
intercity freight travel involves pipeline, water, rail,
and trucking.
Urban passenger travel involves auto or public
transit;
urban freight is primarily by truck.
Chapter 2 Transportation
Systems and Organizations
The principal carriers of freight are rail, truck, pipeline, and water.
Passenger transportation is by auto, air, rail, and bus.
Highway transportation is the dominant mode in passenger travel.
The United States highway system comprises 6.3 million km of roadway.
Chapter 2 Transportation
Systems and Organizations
Chapter 2 Transportation Systems and Organizations
2.2.2 Public Transportation Transit services available to
urban and rural residents
Transit modes:
Mass transit (buses, light rail, rapid transit)
Paratransit (taxi, car rental, dial-a-ride ..)
Ridesharing (carpool, vanpool, share-ride taxi)
Chapter 2 Transportation
Systems and Organizations
Do people prefer to use public transportation?
distance from bus stops
long waits at bus stops
changing buses
long journey time
inconvenience on bus
Chapter 2 Transportation
Systems and Organizations
2.2.3 Highway Transportation
Highway transportation is the dominant
mode in passenger travel and one of
the principal freight modes.
Mode Selection
Solved Examples
Transportation System Chapter 2 Garber P29
• Comparative Advantages of Transportation Modes
• Example 2.1 Selecting a Transportation Mode (Garber p29)
An individual is planning to take a trip between the
downtown area of two cities, A and B, which are 400 km
apart. There are three options available:
• Travel by air. This trip will involve driving to the airport
near city A, parking, waiting at the terminal, flying to
airport B, walking to a taxi stand, and taking a taxi to the
final destination.
Chapter 2 Garber P29
Example 2.1 -cont.
• Travel by auto. This trip will involve driving 400 km
through several congested areas, parking in the
downtown area, and walking to the final destination.
• Travel by rail. This trip will involve taking a cab to the
railroad station in city A, a direct rail connection to
the downtown area in city B, and a short walk to the
final destination.
Chapter 2 Garber P29
Example 2.1 -cont.
• It is a business trip
• The traveller is willing to pay $25 for each hour of travel
time reduced
1. Which mode is selected based on travel time and
cost factors alone?
2. What other factors might be considered?
Chapter 2 Garber P29
Example 2.1 - Solution:
• Since travel time is valued at $25/hr, the
• following costs would be incurred:
• Air: 250 + 25(5) = $375
• Auto: 200 + 25(8) = $400
• Rail: 150 + 25(12) = $450
• In this instance, the air alternate reflects the lowest
cost and is the selected mode.
• Other factors:
• Safety, reliability and convenience.
Highway Project
Development Process
Transportation Systems and
Organizations
Chapter 2 Transportation
Systems and Organizations
2.2.3 Highway Transportation The Highway Project Development Process
1. Planning (6 to 24 months)
2. Design (15 to 24 months
3. Environment (9 to 36 months)
4. Right-of-Way (6 to 21 months)
5. Construction (12 to 36 months)
Thus, total project time can range from 4 to 12 years, depending on the physical characteristics, scope, and community support for the project.
Chapter 2 Transportation
Systems and Organizations
Six-step process for transportation projects:
1. Select Project
2. Investigate Alternates
3. Obtain Final Approval
4. Develop Project Design
5. Prepare for Construction
6. Construct the Project
Chapter 2 Transportation
Systems and Organizations
Cost of highways…..
Estimate the cost of building 1km length of a
30m wide road.
Sources of Funds for Highways
1. Highway users (direct taxes)
2. Property owners
3. Government (general taxes)
Highway Finance
Solved Example
Chapter 2 Garber P33
Example 2.2 Computing the Toll to Maximize Revenue Using a
Supply- Demand Curve :
• A toll bridge carries 5000 veh/day. The current toll is 150
cents. When the toll is increased by 25 cents, traffic volume
decreases by 500 veh/day.
• Determine the amount of toll that should be charged such
that revenue is maximized.
• How much additional revenue will be received?
Chapter 2 Garber P33
• Example 2.2 - Solution:
• Let x = the toll increase in cents.
• Assuming a linear relation between traffic volume and cost,
the expression for V is:
Chapter 2 Garber P33
• Example 2.2 - Solution:
Chapter 2 Transportation
Systems and Organizations
Figure 2.7 Dwight D. Eisenhower System of Interstate and Defense Highways
Chapter 2 Transportation
Systems and Organizations
Figure 2.8 National Highway System
Chapter 2 Transportation
Systems and Organizations
Chapter 2 Transportation
Systems and Organizations
Transportation Organizations 1. Private Transportation Companies
2. Regulatory Agencies
3. Federal Agencies
4. State and Local Agencies and Authorities
5. Trade Associations
6. Professional Societies
7. Users of Transport Services
Chapter 2 Transportation
Systems and Organizations
2.1.1 Comparative Advantages of
Transportation Modes
Students are requested to read this topic
and to discuss it in the next lecture
Roads and highway network
• principal types of road pattern in urban areas.
Roads and highway network
• Gridiron
• Linear pattern
• Radial pattern
• Gridiron Advantages:
1. Easier for surveyors to set out, using straight lines and rectangular co-
ordinates.
2. It encourages an equal spread of traffic over the grid, therefore, the
impact at particular location is reduced.
3. It facilitates the implementation of one-way street systems.
4. If there is a central business area in the middle of the grid, it is easy for
through traffic to bypass it.
Disadvantages:
1. Extra distances must be travelled when going in a diagonal direction.
2. Providing a diagonal route has an unfortunate effect on the buildings
producing acute angles.
Roads and highway network
• Gridiron
Omar
Elmokhtar
Example of Gridiron System Part of Gaza
Roads and highway network
• Linear pattern
Advantages:
1. Main traffic flow is canalised into one major roadway.
Disadvantages:
The major roadway serves as a route both to the completely internal
traffic and for the internal-external traffic as well as for external-internal
and through traffic...
This leads to congestion and the major roadway becomes overloaded.
Roads and highway network
• Linear pattern
Example of Linear System Part of Nabuls
Roads and highway network
• Radial pattern
Roads and highway network
Moscow city
• Radial pattern
Mainly in old cities
Advantages:
Providing a direct access to the town centre.
Disadvantages:
1. Concentration of traffic generators within the central area
2. Radial roads converging on the main sources of attraction
3. Lack of suitable bypass routes for through traffic.
Roads and highway network
• Radial pattern
Chapter 1
1.5 Roads and highway network
Example of radial System Part of London
• Radial pattern
Example of radial System
Erbil, Iraq
Roads and highway network
Road classification
• Road classification
Road classification (road hierarchy concept)
Roads
are classified as follows:
In the USA
Arterials:
Principal (freeways)
Minor
Collector streets
Local streets
Source: O’Flaherty (2006), page 140
See Table 6.5, O’Flaherty (2006), page 142
Road classification
Urban Roads
are classified as follows:
In the UK
Primary Distributor
District Distributor
Local Distributor
Access roads
Pedestrian streets
Rural Roads
are classified as follows:
In the UK
Primary Routes (motorways)
Secondary roads:
A roads
B roads
Source: O’Flaherty (2006), page 141
Chapter 1
1.6 Road classification
Source: O’Flaherty (2006), page 142
Road classification
Source: O’Flaherty (2006), page 142
Road classification
Source: O’Flaherty (2006), page 142
Road classification
In Gaza (Palestine): Main Road Serves for national or inter district traffic
Regional road Branching off from, or lining, main roads
Access Road Leading from a main or regional road to a certain
point within a locality
Road classification
Roads in Gaza
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مشاكل وتوصيات -حالة الطرق المرورية في قطاع غزة
محمد علي الكحلوت. د. أ
مجلة جامعة الملك سعود
غزةمدينة النقل البري في شبكة
2012، عام رسالة ماجستير
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