Traffic & Highway Engineering - الصفحات الشخصيةsite.iugaza.edu.ps/ysarraj/files/2016/08/Ch-02.pdf · Transportation System Chapter 2 Garber P29 • Comparative Advantages

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.



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.



2.1.1 Comparative Advantages of

Transportation Modes

Students are requested to read this topic

and to discuss it in the next lecture



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.



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.



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.





2.2 MODES OF TRANSPORTATION

2.2.1 Freight and Passenger Traffic

Intercity freight transportation

Principal mode:

Highways (truck)

Railroads

Water

pipelines



2.2 MODES OF TRANSPORTATION

Intercity passenger transportation

Principal mode:

Highways (automobile)

Air

Transit (bus)

Railroads



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.



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

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)



Do people prefer to use public transportation?

distance from bus stops

long waits at bus stops

changing buses

long journey time

inconvenience on bus



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.


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?


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



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.



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



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


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?


• 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:


• Example 2.2 - Solution:



Figure 2.7 Dwight D. Eisenhower System of Interstate and Defense Highways



Figure 2.8 National Highway System





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



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.


• 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.


• Gridiron

Omar

Elmokhtar

Example of Gridiron System Part of Gaza


• 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.


• Linear pattern

Example of Linear System Part of Nabuls


• Radial pattern


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.


• 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


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


In the UK

Primary Distributor

District Distributor

Local Distributor

Access roads

Pedestrian streets

Rural Roads


In the UK

Primary Routes (motorways)

Secondary roads:

A roads

B roads


Chapter 1

1.6 Road classification


Road classification


Road classification


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

Read

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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Traffic & Highway Engineering - الصفحات الشخصيةsite.iugaza.edu.ps/ysarraj/files/2016/08/Ch-02.pdf · Transportation System Chapter 2 Garber P29 • Comparative Advantages