Question

Travel demand modeling plays an important role in urban transportation planning as it helps planners explain and predict behavior of consumers of transportation services. The traditional Urban Transportation Planning System (UTPS) Four-Step Procedure has been a center piece of travel demand analysis. However, a number of alternative approaches and improvements have been developed and implemented over the years.

Project Objectives

The objectives of this term paper are:

1. To document the history and theoretical background of travel demand modeling

2. To identify alternative approaches for modeling travel demand

Project Questions

1. What are the basic principles and theories behind the traditional Four-Step Procedure for travel demand analysis? Demonstrate by formula or numerically, or otherwise.

2. What are the advantages of the Four-Step Procedure for travel demand analysis? Cite examples, if any.

3. What are the limitations of the Four-Step Procedure for travel demand analysis? Give specific examples (numerically or otherwise)

4. What alternative approaches have been used to address the limitations of the traditional Four-Step Procedure for travel demand analysis? Give specific examples (numerically or otherwise)

Answer 1

1. ans- travel demand modelling is a important part of decision making process. there are large numbers of factors efecting travel demand , model consider all those factors and use principal of equilibarium to calculate travel demand.The basic principal behind four step modelling is that considering major factors with thier contribution in demand to find actual travel demand .modelling of deman thus implies a procedure for predicting what travel decision people would like to make given the generalised travel cost of each alternatives.the basic decision include choice of rout, mode and destination.,

2. ans- advantages of four step travel deman modellings are listed below:-

It is easy in calculation and consider major factors effecting demand.

regression analysis used help to find each factors in their proportionality.

Model generated using one city can be used to other with same feature.

3. ans-The traditional four step modelling has some shortcoming listed below:-

It consider only zone or household attribute as factor governing travel demand but other factors are also there like insensitivity on transit accesibility. number of purpose of trip are limited. also linear regression is ysed for trip generation modelling which is not true for all conditions.

In trip distribution it is assumed that average travel time would remain constant in the future as well as through the day in gravity model which is not true.the socioeconomic dynamics that may occure during the planning horizon are ignored. also effect of vehicle speed are ignored.

In modal split non motorized travel modes are neglected which can have significant share in demand.

4. ans-to overcome defficiency in four step model some alternative method has been developed as land used transport model

a) lowry model: this consider three principle component , Population, Employement, and comminication between population and employement.

b) Garin-lowry model-It consider cosider the above factor but in employement basic and service employement.