chapter 4 principal stages in the urban transportation planning process

CHAPTER 4

PRINCIPAL STAGES IN THE URBAN TRANSPORTATION PLANNING

PROCESS

STUDY OBJECTIVES

At the end of this chapter students will be expected to be able to define, where applicable and explain each of the following elements and stages in the urban transportation planning process:

travel demand forecasting; the formulation of goals and objectives; the collection of basic data; the establishment of quantifiable relationships between

movement and land use; trip generation; the prediction of future land-use, populations and economic

characteristics;

STUDY OBJECTIVES cont’

The preparation of a land use plan; predictions of future origins, destinations and

the distribution of person movements; trip distribution; the estimation of future person movements

carried by different modes of travel; network planning; the assignment of future trips to the proposed

transport networks etc.

4.1 INTRODUCTION

4.1.1 TRAVEL DEMAND FORECASTING AND THE TRANSPORTATION PLANNING PROCESS.

• The three stages [basic framework] essential to any transportation planning process:

i. A survey and analysis stage which establishes the present demand for movement and how this is met, and the relationships between this demand for movement and the urban environment;

4.1.1 TRAVEL DEMAND FORECASTING AND THE TRANSPORTATION PLANNING PROCESS cont’

ii. A prediction and plan formulation stage, which projects for some future date the likely travel demand, based on the data collected and the relationship established in the survey and analysis stage, and puts forward proposals to meet this demand.

iii. An evaluation stage which attempts to assess whether the transportation proposals put forward satisfy the projected demand for: travel with adequate safety, capacity and levels of service to provide the maximum benefits to the community with minimum costs.


The 11 principal stages in the urban transportation planning process are:

1. Explicitly formulating goals and objectives;2. Collecting land-use, population, economic and

travel pattern data for the present day situations;

3. Establishing quantifiable relationships between present-day movements and the land-use, population and economic factors;


4. Predicting land-use, population and economic factors to the target date for the study and the development of a land-use plan(s);

5. Predicting the origins, destinations and distribution of the future movement demands, using the relationships established for the present day situation and the predicted land-use population and economic factors (trip generations and trip distribution);


6. Predicting the person movements likely to be carried by the different modes of travel at the target date (modal split);

7. Developing the highway and public transport networks to fit the predicted land-use plan and accommodate the estimated pattern of movements.


8. Assigning predicted trips to alternative co-ordinated transport networks/systems (traffic assignment);

9. Evaluating the efficiency and economic viability of the alternative transport networks in terms of economic and social costs and benefits;


10. Selecting and implementing the most appropriate transport networks;

11. Monitoring and reviewing the chosen transportation policies or plans.


4.1.7 ESTIMATIONS OF FUTURE PERSON MOVEMENTS CARRIED BY

DIFFERENT MODES OF TRAVEL

Factors that affect an individual’s choice of mode of transport for a particular journey are:

• income, • the availability and convenience of alternative

modes of transport and • length of journey

4.1.11 THE SELECTION OF A BALANCED TRANSPORT SYSTEM

• The decision as to which transport system best serves the needs of the community cannot be made by the transportation planning process.

• The transportation planning process is basically an aid to orderly decision-making and not the precise instrument that some people like to think it is.

4.2 COLLECTION OF BASIC DATA

4.2.1 INTRODUCTION• An essential first step in any planning process

is the collection of information about the existing situation.

4.2.1 INTRODUCTION cont’

The transportation planning process therefore involves the accumulation of basic data i.e.:

Characteristics of present-day travel patterns in the area under consideration must be collected;

The future distribution of land use and population dispersion must be considered;

Adequacy of existing transportation facilities must be determined and spare capacity estimated.

4.2.3 SUBDIVISION OF AREA INTO TRAFFIC ZONES

• The area being surveyed is divided into zones so as to make it intelligible, open to analysis and suitable for the assignment of trips.

• Traffic zones are therefore the basic unit of analysis for the transport planning process.

• Trip data should be coded to traffic zones, and socio-economic and land-use data should be inventoried on a zonal basis.

• The zonal system is then used as a basis to determine the origins and destinations of all trips within the transport authority’s area.

• The size of a traffic zone is influenced by the:1. size of the transport authority, 2. the density of population, and 3. the distribution of economic activity in the

transport authority’s area.

4.2.3 SUBDIVISION OF AREA INTO TRAFFIC ZONES

4.2.5 PLANNING AND ECONOMIC DATA

• Traffic is therefore a function- of activities, and is concentrated in towns because activities are concentrated there.

Factors that effect traffic are:Population and employment dataIncome– the total number of cars owned;– the number of households with nil, one and two or more

cars:– the number of owner-occupied dwellings, council-rented

dwellings,

4.2.5 PLANNING AND ECONOMIC DATA cont’

Income cont’– other rented dwellings furnished and unfurnished

and other dwellings;– the socio-economic group of the chief economic

supporter of the household;– the social class of the chief economic supporter of

the household.

Retail salesAttendance at establishments schools,

colleges, and other educationalOther land-use data– It has been found that both the amount and the

characteristics of travelare influenced by the intensity of development of land.

4.2.5 PLANNING AND ECONOMIC DATA cont’

4.3.2FACTORS INFLUENCING TRIP GENERATION

(A)LAND-USE FACTORS• Land use is a convenient way of classifying

trip generating activities. Different uses of land produce different trip

generation characteristics.• For example, land given over to shopping

development or offices could be expected to generate more trips than open space.

4.3.2FACTORS INFLUENCING TRIP GENERATION cont’

The intensity with which different activities are pursued can produce different generation characteristics:

For example, one acre of residential and developed at a high density (flats) would be likely to produce more total person movements than one acre of land developed for residential purposes at a low density (houses).

Land-Use can be broadly classified into 3 uses:1. Residential land use2. Commercial and Industrial land use3. Educational and Recreational land use


(B) THE HOME• Family size. – Travel is a function of human activity. – Thus a relationship should exist between the

number and frequency of trips made from the home and family size.


• Motor vehicle ownership. – The number of vehicles available for use by each

household influences trip generation.• Type of dwelling unit. – The more permanent types of dwelling unit reflect

a high degree of integration into the local community on the part of the household and lead to a high rate of trip generation.


• Occupied residents. – The occupation of the head of the household is one

of the major indicators of the standard of living enjoyed by the family and reflects to a certain extent the family income.

• Family income. – The ability to pay for a journey affects the number

of trips generated by a household. – Family income tends to be related to levels of motor

vehicle ownership.


4.5 MODAL SPLITMODAL CHOICE

4.5.1 INTRODUCTION• Trip-makers can select between several travel

modes.• These may include driving, riding with someone

else, taking the bus, walking, riding a motorcycle etc.

• A modal choice or modal split model is concerned with the trip-makers behaviour regarding the selection of travel mode.


• Assumption for this model: of a given total travel demand the proportion carried by bus, taxi, railway or private motor car will depend on the standing of each mode of transport in relation to its competitors.

The measure of competitiveness is usually derived from an analysis of three sets of factors:

i. Characteristics of the journey to be made,o e.g. length, time of day the journey is made,

purpose of the journey;


ii. Characteristics of the person making the journey o e.g. car-ownership, income, social standing:

iii. Characteristics of the transportation system o e.g. travel time involved, costs, and accessibility,

comfort.


• In estimating modal choice, trip makers should be treated as two separate groups

• (i) captive public transport users who do not have access to a car for the particular trip under study: and

• (ii) choice public transport users who are in a position to choose whether to use car or public transport for a particular journey.

• Income, sex, and age are the three main factors in determining ‘captive’ or ‘choice’ status.


4.5.2FACTORS INFLUENCING MODAL CHOICE

Factors the influences modal choice are:(A)CHARACTERISTICS OF THE JOURNEY– Journey length– Journey purpose

4.5.2FACTORS INFLUENCING MODAL CHOICE cont’

(B)CHARACTERISTICS OF THE TRAVELLER– Socio-economic characteristics of the households:

income;– car ownership;– family size and structure:– density of residential development– type of job undertaken; and– the location of workplace.

(C) CHARACTERISTICS OF THE TRANSPORTATION SYSTEM– Relative travel time– Relative travel cost– Relative level of service– Accessibility indices

4.5.2FACTORS INFLUENCING MODAL CHOICE cont’

4.6.2NETWORK PLANNING

Two basic alternative modes of public transport are generally examined in the development of alternative public transport networks.

1. Firstly, rapid mass transit (e.g. underground or suburban railways) and

2. secondly the motor bus.

4.6.4DIVERSION CURVES IN TRAFFIC ASSIGNMENT

• For any trip from one zone to another there are usually several alternative routes for the person making the trip.

• Each route has its own ‘travel resistance’ based on its distance, travel time, speed and level of service.

• These characteristics are evaluated by the driver before choosing a particular route.

4.6.4DIVERSION CURVES IN TRAFFIC ASSIGNMENT cont’• A route with a high travel resistance (e.g. a

busy urban street with bus stops, parked cars, intersections and pedestrians), will be used by less drivers than a comparable route with low travel resistance.

4.7 EVALUATION OF TRANSPORTATION PROPOSALS

4.7.1 INTRODUCTION• The evaluation stage of the transport planning

process attempts to assess whether the transportation proposals put forward satisfy the projected demand for travel with adequate safety capacity and levels of service to provide the maximum benefits to the community with minimum costs.


• Evaluation involves the assessment of the comparative merits of different courses of action.

• Thus it is concerned with analysing a number of alternative plans or projects in order to identify systematically and logically their comparative advantages (benefits) and disadvantages (costs).

4.7.2COST-BENEFIT ANALYSIS DEFINED

A number of different methods are used to evaluate proposals for development. The most important methods include:

1. Financial appraisal, – Concerned with estimating the future streams of

capital and operating costs and revenues resulting from the implementation of investment projects;

4.7.2COST-BENEFIT ANALYSIS DEFINED cont’

2. Check list of criteria, – whereby alternative proposals are ranked

subjectively, in order, in relation to a number of specified criteria;

3. Goals achievement analysis, – where the extent to which alternative proposals

will achieve a predetermined set of goals and objectives is determined;

4. Costs in use– which estimates both private and public capital

and operating costs involved in urban developments;

5. Threshold analysis– where the capital and operating costs of location

sare investigated and crucial thresholds in relation to the scale of development and the provision of services are identified;


6. Cost-benefit analysis, – where the social worth of public sector projects

is appraised

7. Planning balance sheet analysis, – which is a particular application of the cost-

benefit analysis approach.


• Large-scale transportation proposals are usually assessed by means of a cost-benefit analysis, which aims to compare the costs and benefits associated with alternative schemes.


4.7.2 COST-BENEFIT ANALYSIS DEFINED

• Cost-benefit analysis is a practical way of assessing the desirability of projects, where it is important to take

• the long view – in the sense of looking at repercussions in the further, as

well as the nearer, future and • a wide view – in the sense of allowing for side effects of many kinds on

many persons, industries, regions, – i.e. it implies the specification and evaluation of all the

relevant costs and benefits.

Thus; a comprehensive cost-benefit analysis should include the following:

(i) Financial assessment - to determine a project’s need for funds and also whether the project is viable from a financial point of view:


(ii) Economic analysis - to determine the scarcity value of goods and services used in the project and arising from the project (based mainly on opportunity-cost considerations):

(iii) Social analysis - to determine the effect of the project on the distribution of welfare and other social circumstances.


4.7.6 - PROCEDURE FOR THE APPLICATION OF COST-BENEFIT ANALYSIS

(D) IDENTIFICATION AND QUANTIFICATION OF SOCIAL IMPACTS

The following social consequences of a project should be addressed:

1. Distributional effects between income groups, population groups or geographical groups;

2. Welfare consequences:3. Political and constitutional implications;

4.7.6 PROCEDURE FOR THE APPLICATION OF COST-BENEFIT ANALYSIS cont’

4. Strategic consequences;5. Prestige;6. The creation of job opportunities;7. The achievement of economic independence;8. Population movements.

(G) RECOMMENDATION AND COMPLETION OF THE REPORT, SUMMARY AND SUMMARISING TABLE

The summary, to give the decision-maker an overview of the most important aspects of the analysis, should cover the following:

i. An introduction;


ii. The project identification including the determination of the need and the technical solutions;

iii. An explanation of the aim of the analysis, – i.e. to identify the financial, economic and social

implications of the alternatives in order to identify the best alternative


iv. An explanation of any considerations that may lead to the elimination of any of the alternatives, – for example strategic or political implications or

legal restrictions;

v. The result – which include the financial and economic results

and the social, welfare, political, constitutional and strategic consequences;


vi. Sensitivity and critical considerations, – e.g. an explanation that the success of the

project may depend on the completion and/or success of another project of projects;

vii. A well-thought out and reasonable recommendation.


4.8.2 ASPECTS OF TRANSPORT SYSTEM PERFORMANCE

The performance of a transport system has four main aspects, i.e.:

(A) EFFICIENCY– Efficiency is concerned with the operational

aspects of the system i.e. the consumption of resources (e.g. labour, energy, money) and measures the performance of the system from the operator’s point of view.

4.8.2 ASPECTS OF TRANSPORT SYSTEM PERFORMANCE cont’

(B) EFFECTIVENESS– Effectiveness is concerned with the performance

of the transport system within its external environment i.e. from the users’ point of view

(C) EQUITY, FAIRNESS AND JUSTICE– individuals are treated in a like manner by the

governent or transport authority in terms of funding, the distribution of benefits, compensation and who pays the costs of providing transport.

(D) ACCESSIBILITY– Indicators of the accessibility to opportunities

(jobs, shops, recreational facilities, medical care, etc.) usually include door-to-door travel time and the amount of activity (or opportunities) at the specific location.

4.8.2 ASPECTS OF TRANSPORT SYSTEM PERFORMANCE cont’

4.9 SUMMARY

In summary then, the initial core activities of a basic transport plan include:

A description of the existing transport situation (status quo):

A description of mobility needs (which may include a detailed demand or market analysis):

The preparation of a spatial framework:A travel demand estimation (based on selected

future, scenarios):

4.9 SUMMARY cont’

The development of a vision of desired future conditions, as well as goals and objectives to be achieved with the implementation of the transport plan:

A statement of duly adopted policies and how they address relevant local, provincial and national goals and objectives:

The setting of transport standards for both Infrastructure and services.

Data collection and demand forecasting:• Data collection and demand forecasting (i.e.

trip generation, trip distribution, modal split, and traffic assignment) are therefore the first and most basic steps of transport analysis and therefore planning.

• Based on this, various proposals can be made, evaluated, implemented and marketed, and then monitored and reviewed.

4.9 SUMMARY cont’

As has already been mentioned previously the role of the government is most important in this regard.

The advantages of the transport authority undertaking the transport planning activities are:

i. it is familiar with the study area and has the most ready access to existing data and materials required for the compilation of site plans;

4.9 SUMMARY cont’

ii. with its professional staff, it is most familiar with the existing problems of the area which facilitates the formulation of objectives and influences the terms of reference for the preparation of the plan;

iii. it may be drawn from a wide body of municipalities within the area and is thus in the best position to identify the aspirations and transport needs of people and organisations within its jurisdiction;

4.9 SUMMARY cont’

iv. it is best qualified to decide the objectives of the integrated transport plan, to determine the organisational structure to be employed throughout and to decide on the nature of public involvement in the planning processes;

v. it may facilitate the early definition of the objectives which must be clear from the outset of the design of any planning process;

4.9 SUMMARY cont’

vi. it is in the best position to prepare information for the financial statement which will require in-depth knowledge of the provisions of the national and provincial transport legislation as they relate to each transport authority);

vii. it can also most easily provide information on its financial and human resources

4.9 SUMMARY cont’

viii.it also best knows the local government legislation and the inter-governmental financial flows as determined by the Financial and Fiscal Commission.

• The END

4.9 SUMMARY cont’

chapter 4 principal stages in the urban transportation planning process

Documents

travel demand forecasting

likely travel demand

present demand

transportation proposals

prediction of future

projected demand

predicted land

land use trip generation