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CHAPTER 8 THE THEORY OF URBAN PASSENGER TRANSPORT MODES CHAPTER 8 THE THEORY OF URBAN PASSENGER TRANSPORT MODES

CHAPTER 8 THE THEORY OF URBAN PASSENGER TRANSPORT MODES - PowerPoint Presentation

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CHAPTER 8 THE THEORY OF URBAN PASSENGER TRANSPORT MODES - PPT Presentation

GUIDELINES FOR PASSENGER TRANSPORT IN SOUTH AFRICA A MULTI MODAL ANALYSIS 81 Introduction Transport and transport systems are very complex and difficult analyse No rational policy and planning of urban transport can be achieved without a thorough understanding of the characteristics of d ID: 674402

public transport higher cont

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Slide1

CHAPTER 8THE THEORY OF URBAN PASSENGER TRANSPORT MODES

GUIDELINES FOR

PASSENGER TRANSPORT IN SOUTH AFRICA

A MULTI MODAL ANALYSISSlide2

8.1 IntroductionTransport and transport systems are very complex and difficult analyse.

No rational policy and planning of urban transport can be achieved without a thorough understanding of the characteristics of different modes.Slide3

8.2 Transportation System Evolution in a Model Urban AreaTransport system must be understood and analyze without factors that would influence you, like:

investment,

pricing, and

regulatory policies

favouring

one mode

A conceptual analysis based on a model of an urban area of changing population and size will therefore be used.Slide4

8.2 Transportation System Evolution in a Model Urban Area cont’The Model:

represents a residential area that grows from a small settlement to a large metropolis

Requirements for transport change through

from low volume, dispersed travel to

high volume, heavily concentrated travel along a number of major arterials.

Entire range of requirements is observed and the

optimal sequence

of transport modes through the entire spectrum of capacities and performance levels is defined in a systematic way.Slide5

The analysis is divided into four growth periods, which correspond approximately to small settlements, [up to 100,000 –population size]towns, [100,000 to 500,000]

medium-size and , [500,000 to 2 million]

large cities [over 2 million]

8.2 Transportation System Evolution in a Model Urban

Area cont’Slide6

8.3. A Description of Typical Rights-of-way (R/W)8.3.1 Right-of-way: Category A

Ultimate in systems,

carrying capacity and

safety,

Exclusive right-of-way is given along its total length with no pedestrian or vehicle conflict.

It may be either elevated, at surface level, or underground, depending on availability of space and land values.Slide7
Slide8

8.3. A Description of Typical Rights-of-way (R/W) cont’

8.3.2 Right-of-way: Category B

Longitudinally separating the right-of-way from other traffic by devices such as

kerbs

, barriers and fences

Result –

capacity of the system is dramatically increased and

pedestrian vehicle conflict limited to intersections where it can be

minimised

by orderly control of using traffic signal systems.

Far higher average and overall operating speeds can be maintained and a clear advantage in terms of travel time is achieved, especially in congested city town streets.Slide9
Slide10
Slide11

8.3.3 Right-of-way: Category Cthe right-of-way shared with other users. The operational safety of the system is entirely the responsibility of the driver; consequently vehicles must have braking characteristics similar to those of ordinary road vehicles.

Nevertheless, some degree of priority can be given at traffic signal controlled intersections to give preference over normal vehicular traffic.

8.3. A Description of Typical Rights-of-way (R/W

) cont’Slide12

8.4 Transportation System EvolutionWe’ll follow the growth of the hypothetical settlement as it grows through the following stages:

small settlement

town

medium - size city

large citySlide13

8.4 Transportation System Evolution cont’

8.4.1 Small settlement - walking and private cars

Step1: Walking

Step 2: Private Cars

Step 3: Common Carriers

(Taxis)

Private cars and taxis

comprise an ideal transportation system for small, low-density settlementsSlide14

8.4.2 Towns: arterials and public transportStep

4 - Wider Roads and

Streets

(multilane roads and streets)

The capacity of the transport

system must be increased.

Two measures are most logical:

widening

of the paths, and

introduction of

larger cabins (busses)

. Slide15

8.4.2 Towns: arterials and public transport cont’

Construction of higher-capacity ways (paths) brings:

Advantages

:

Higher levels of service. (L/S)

Lower unit transportation costs.

Stimulus to economic growth (result of the preceding two).

Disadvantages

High investment requirements.

Negative environmental impact of wide paths and large cabin storage facilities.Slide16

Step 5: Larger Vehicles and Formal Public TransportCapacity increase through introduction of large cabins can be achieved only with common carrier (public transport) service.Midibuses -

For low passenger volumes, medium-capacity cabins that stop wherever passengers want

the

bus -

As the volume increases it becomes necessary to introduce large-capacity cabins

8.4.2 Towns: arterials and public

transport cont’Slide17

Changing public transport from small to large:Large public transport vehicles differ to smaller ones by:travel along fixed routes,

stop at predetermined locations, and

serve large numbers of persons

Schedules are fixed

and

It has regular frequencies

Fares are somewhat lower

8.4.2 Towns: arterials and public

transport cont’Slide18

(L/S = Level of service)(R/W = Right of way)Slide19

Introduction of formal public transport service results in the following changes:Advantages:Lower-cost transportation becomes available to all persons in the area served.Simple and conveniently scheduled service is provided throughout the public transport network.

Increased street capacity: higher L/S for all vehicles.

Less congestion and its negative impacts.

8.4.2 Towns: arterials and public

transport cont’Slide20

Disadvantage:Since it is difficult to charge small-cabin drivers the full cost (including social) of their travel, public transport must often be subsidised to attract its potential passengers.

8.4.2 Towns: arterials and public

transport cont’Slide21

Replacement of medium by large public transport vehicles or units (TUs) results in:Advantages:Higher transporting capacity.Lower cost per unit capacity, mostly due to higher

labour

productivity.

Greater riding comfort.

Disadvantage

:

Lower service frequency for given demand.

8.4.2 Towns: arterials and public

transport cont’Slide22

Conclusion:(1) optimal vehicle size increases with passenger volume and(2) service with adjustable routing and schedules should be replaced (or complemented) by fixed routes and schedules as passenger volumes increase.

(Learners are reminded of the conclusion in chapter 6 where it was stated that both the formal and informal sectors should co-exist where necessary)

8.4.2 Towns: arterials and public

transport cont’Slide23

8.4.3 Medium-size cities: technology mode separation and guidedSlide24

Step 6: Separation of public transport on its own right- of-way [from category C to B]create separate rights-of-way for different types of cabins, so that a smooth flow, with no friction from other vehicles, pedestrians, and so on, is obtained. Longitudinal separation (R/W category B) is the 1step for the reduction of interferences, because conflicts at intersections of paths can be regulated through traffic control devices

Public modes should be given separate rights-of-way first because the carry 5-50 times more people

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide25

Longitudinal separation of public transport vehicles (R/W category B) results in:Advantages:Higher level of service and system performance.Stronger system image and identity.

Higher passenger attraction (consequence of the above two).

Lower unit operating cost.

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide26

Advantages cont’:Stronger impact on land use and urban form due to permanence.Changed traffic conditions, depending on whether the public transport R/W is outside or within existing streets (e.g., curbed median).

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide27

Disadvantage:Changed traffic conditions, depending on whether the public transport R/W is outside or within existing streets (e.g., curbed median).Additional land required.Substantial investment and construction required.

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide28

Step 7 - Introduction of Guided Public TransportGuided modes, compared with steered public transport modes, differ in the following:Advantages:

Higher capacity and productivity due to operation of trains.

Lower operating cost per unit of offered capacity.

Electric traction possible + Greater reliability and safety (fail-safe operation).

Narrower R/W.

Operation in tunnels, on viaducts, and in park areas possible without significant environmental damage.

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide29

Disadvantage:Less compatible with other traffic in street operation.Limited to the guideway network only, therefore uneconomical for extensive routing in low-density areas.

Lower operational flexibility (rerouting, detours, etc.).

Requires higher investment.

8.4.3 Medium-size cities: technology mode separation and

guided cont’Slide30

8.4.4 Large cities: addition of fully controlled waysSlide31

8.4.4 Large cities: addition of fully controlled ways cont’Step 8: Construction of freeways

heavy travel volumes in many corridors and

large spatial size,

requires higher performance transportation

Solution:

Fully Controlled Rights-of-way

(that is category A) for major routes of both private and public modes.

speed, capacity, and reliability for >2mil peopleSlide32

Step 9 - Fully Controlled Right of Way for Public Transport (rapid public transport)Category A, compared with Category B R/W, gives public transport modes:Advantages:

Higher performance (capacity-long trains, speed, reliability, etc.).

Higher L/S.

Lower operating costs per unit capacity.

8.4.4 Large cities: addition of fully controlled

ways cont’Slide33

Advantages cont’:Stronger image and identity.Higher passenger attraction (result of the preceding three).Stronger land use impacts.

Possibility of automation.

8.4.4 Large cities: addition of fully controlled

ways cont’Slide34

Disadvantage:Need for grade separation of the entire RIW, resulting inHigh investment needs.Disruptions of the corridor during the construction.Less extensive network (result of the preceding three).

8.4.4 Large cities: addition of fully controlled

ways cont’Slide35

Step 10: Full AutomationThere is only one additional major improvement that can be made: full automation of train (trains without crews). technology of line-haul public transport > ultimate step of development that can be practically achieved.

Full automation requires two features:

R/W category A, and

guided technology.

Rail systems are best candidates

8.4.4 Large cities: addition of fully controlled

ways cont’Slide36

8.5 Review of Modal FeaturesThere is a strong interdependence between the volume of travel and the characteristics of modes optimal for a given application.

Serious transportation problems in many cities have been created, for example,

when extensive freeway networks were built to accommodate and stimulate motor car travel, while public transport consists only of buses in mixed traffic.Slide37

8.5 Review of Modal Features cont’Step 1, walking, remains essential for cities of all sizes (actually, it is often more important in large cities than in small settlements), yet many cities have neglected it while they worked on accommodating

motorised

traffic through steps 2, 4, and 8. Slide38

8.6 Higher performance modesThe evolutionary development process shows that with increasing density of travel, each new modal feature results in:

Higher system performance, including capacity, speed, and service quality.

Greater passenger attraction (consequence of the preceding result).

Higher initial investment.

Lower operating cost per unit capacity.Slide39

8.7 ConclusionAs the town expanded and grew, not only were new modes necessary, but new methods of operation and new infrastructure was required to operate and accommodate them effectively.

This chapter also noted that there is no ‘exact’ economic boundary between modes and that higher-performance modes can be introduced at an earlier stage because of their higher passenger attraction.