An Integrated Transportation use Modeling System for

1 downloads 0 Views 7MB Size Report
44. 5.1 Summary ofthe Lafayette area in 1970, 1980, 1990,1993,2000. 76 ..... inability of the model to account for endogenous congestion and route choice, .... Another Lowry-Garin type model is called HLFM 11+ (Highway Land-Use Forecasting ..... indirect utility received by a type n household that resides in zone i with a.
Purdue University

Purdue e-Pubs Joint Transportation Research Program

Civil Engineering

1-1998

An Integrated Transportation use Modeling System for Indiana Andrew Ying-Ming Yen Jon D. Fricker

Yen, Andrew Ying-Ming and Fricker, Jon D., "An Integrated Transportation use Modeling System for Indiana" (1998). Joint Transportation Research Program. Paper 20. http://docs.lib.purdue.edu/jtrp/20

This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information.

Joint

Transportation

II JTRP

Research

Program

FHW A/IN/JHRP-96/l 8 -©I Final Report

AN INTEGRATED TRANSPORTATION LAND USE MODELING SYSTEM FOR INDIANA Parti

Andrew Ying-Ming Yen Jon D. Fricker

August 1998

Indiana

Department of Transportation

Purdue University

8

Report

Final

FHW A/IN/JHRP-96/1 AN INTEGRATED TRANSPORTATION LAND USE MODELING SYSTEM FOR INDIANA PARTI by

Andrew Ying-Ming Yen Research Associate

and Jon D. Fricker Professor of Civil Engineering

Purdue University School of Civil Engineering

JOINT TRANSPORTATION RESEARCH Project No. File

Prepared

in

PROGRAM

C-36-54ZZ

No. 3-3-52

Cooperation with the

Indiana Department of Transportation and the

U.S. Department of Transportation Federal

The contents of this

Highway

Administration.

report reflect the views of the authors,

the accuracy of the data presented herein.

who

The contents do not

are responsible for the facts and

necessarily reflect the official

views or policies of the Indiana Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation.

Purdue University

West Lafayette IN 47907-1284 August 1998

Digitized by the Internet Archive in

2011 with funding from

LYRASIS members and Sloan Foundation;

Indiana Department of Transportation

http://www.archive.org/details/integratedtranspOOyena

8

8

Ill TECHNICAL REPORT STANDARD TITLE PAGE Report No.

1.

2.

Government Accession No.

3.

Recipient's Catalog No.

FHWA/IN/JHRP-96/1 4. Title

and Subtitle

Report Date

5.

August 1998

An Integrated

Transportation Land

Use Modeling System

for Indiana,

Performing Organization Code

6.

Part 7.

I

and Part

II

Authors)

Performing Organization Report No.

8.

Andrew Ying-Ming Yen and Jon D.

FHWA/IN/JHRP-96/1

Flicker

Performing Organization Name and Address Research Program 1284 Civil Engineering Building Purdue University West Lafayette, Indiana 47907-1284

10.

9.

Work Unit

No.

Joint Transportation

Sponsoring Agency

12.

11.

Contract or Grant No.

13.

Type of Report and Period Covered

HPR-2107

Name and Address

Indiana Department of Transportation

Final Report

State Office Building

100 North Senate Avenue

IN 46204

Indianapolis,

Sponsoring Agency Code

14.

Supplementary Notes

IS.

Prepared in cooperation with the Indiana Department of Highways and Federal Highway Administration.

16.

Abstract

The principle objective of this research was

to

develop an integrated model to represent the interrelationships between land use

ISTEA of 1 99 1 and the CAAA of 990. The integrated model includes two major parts: a land-use allocation module and a travel demand module. An interface module has also been built to transform data between these two modules. The land-use allocation module consists of a residential location model, an employment and transportation, subject to the requirements of the

1

location model, a land use potential model, and a land consumption model.

One unique

feature of the residential and

employment location models is that they simultaneously estimate passenger movement by work-to-home, home-to-shop and work-to-shop trips between zones before entering the travel demand module. Then the TRANPLAN-based travel demand module

stages for estimating home-based school, home-based other, non-homeThe land consumption model, which is significantly different from the LANCON procedure of DRAM/EMPAL, is based on micro-economic theory to simulate the profit-maximizing behavior of housing or landowners over time. The major purpose of the land consumption model is to satisfy the need to reach a balance between demand and supply in the housing market during each time period. The land consumption model is also influenced by Anas's work in CATLAS, which did not deal with employment location, but simultaneously considers housing location and employment location. The integrated model can be used to evaluate land use policies and transportation policies. Tests run for the Lafayette area have demonstrated that the model can be used to quantify positive and negative effects of long range carries out trip generation

and

trip distribution

based, external-internal and external-external

transportation and land

The

final report

use plans.

has two parts. Part

I is

the technical report that describes

System (ITLUMS) was developed. Part

ITLUMS, 17.

trips.

the sequence in

II is

which the programs must be

run,

18. Distribution

demand, integrated models, land use

allocation,

Unclassified

Form

DOT F 1700.7 (8-69)

No restrictions.

Use Modeling

FORTRAN programs that make up

files

needed by the

ITLUMS programs.

Statement

This document

is

available to the public through the National

Technical Information Service, Virginia, 22161

land use potentials

19. Security Classif. (of this report)

Indiana Transportation Land

and the format of the input

KeyWords

land use, travel

how the

a separate user's guide, which describes the

20. Security Classif. (of this page)

Unclassified

21. No. of Pages Part

I -

Part

II

28

-158

22. Price

51

TABLE OF CONTENTS

Page

LIST OF TABLES

vi

LIST OF FIGURES

CHAPTER

1.

viii

INTRODUCTION

CHAPTER 2. LITERATURE REVIEW

CHAPTER 3. MODEL STRUCTURE AND METHODOLOGY 3

.

3.2 3.3

3.4 3

.

3.6

Framework Land-Use Allocation Module Land Use Potential Study 3.3.1 Land Suitability Analysis 3.3.2 GIS Database Land Consumption Model Interface Module Travel Demand Module 3.6.1

Simultaneous Location and Trip-distribution Procedures

16 18

26 27 28 28 38 38 38

3.6.3 Trip Distribution

43

Modal

Model

Split

43

Assignment

46

Calibration

CHAPTER 4. DATA REQUIREMENTS AND ANALYSIS 1

16

40

3.6.5 Traffic

4.

5

3.6.2 Trip Generation

3.6.4

3.7

1

Data Requirement

52

66 66

1

Page

CHAPTER 5.1

5

CASE STUDY

Tippecanoe County, Indiana 5.1.1

5.1.2 5.1.3

5.1.4

Land Use Allocation Module Land Use Potential Study Land Consumption Model Travel Demand Model

5.1.5 Policy Test

1

-

5.1.6 Policy Test 2

-

5.1.7 Policy Test 3

-

Improvements of highway network for 20 1 Changes in land use pattern Improvements of highway network for 2015

CHAPTER6 CONCLUSIONS AND RECOMMENDATIONS 6.

Conclusions and Recommendations

76 76 78 85

87 88 91

93

94 119

119

6.2 Future Research

123

6 3 Implementation

124

LIST OF

REFERENCES

Appendix A. Land-Use Potential Study - Scoresheet System Approach Appendix B. Dempster-Shafer Evidence Theory

125

132 135

1

LIST

OF TABLES

Page

Table

3.1

Lot area (square

feet) per dwelling unit,

3.2 Tippecanoe County, Indiana: 1994 data

by

60

district

on auto occupancy

44

5.1

Summary ofthe

Lafayette area in 1970, 1980, 1990,1993,2000

76

5.2

Summary of the

Lafayette area by districts in 1980, 1985, 1990, 1993

98

5.3 Calibrated parameters

ofthe land use allocation module on 1980,

1990 and 1993 data 5.4

The average

99

rents in Tippecanoe

County townships

in

5.5 Estimated coefficients for the existing housing supply in the

5.6

990

100

submodel 100

Lafayette area

Year 2010 population

5.7 Differences in

5.8

1

Year 2010

Year 2010 population forecasts

Retail

5.9 Differences in

forecasts for Policy Test

101

1

for Policy Test

employment forecasts for Policy Test

Year 2010

retail

employment

101

1

102

1

forecasts for Policy Test

5.10 Comparisons of estimated average travel time based on Policy Test

102

1

1

and

base case

5.1

Peak hour Volume/Capacity based on Policy Test 1

103

ratios

on old

US

231

in

1993 and

in

2010 103

Vll

Page

Table 5.12 Year 20 10 Population forecasts Policy Test 2 5.13 Year

2010

Retail

employment forecasts

5.14 Peak hour Volume/Capacity ratios on

104

for Policy Test 2

SR 26

in

1993 and

104

in

2010

based on Policy Test 2

105

5.15 Year 2015 Population forecasts for Policy Test 2

105

5.16 Differences in population forecasts for Policy Test 3

106

5.17 Year 2015 Retail employment forecasts for Policy Test 3

106

5.18 Differences in Year 20 1 5

retail

employment forecasts

107

for Policy Test 3

5.19 Comparisons of estimated average travel time based on Policy Test 3 and

base case

1

5.20 Peak hour Volume/Capacity ratios on Northwestern in

A.

1

B.l

1993 and

Land use

in

2015 based on Policy Test

Avenue and US 52 108

3

134

potential decision-making matrix

Some common

139

evidential intervals

B.2 Probability measures for assessing land

08

suitability

(Dempster-Shafer Theory)

.

145

B.3 Calculation of lower probability

149

B.4 Calculation of upper probability

1

49

LIST

OF FIGURES

Page

Figure

3.1

Framework of Land-Use/Transportation Model

62

3.2 Order of model operation for simulating the dynamics of interaction

between Land use and Transportation 3.3 Structure

3.4

63

of land use potential model

64

The framework of land consumption model

4.1 Forested Land,

65

Tippecanoe County, IN

71

4.2 Distance to Sanitary Sewer System, Tippecanoe County,

4.3

&

Airports, Tippecanoe County,

4.5 Current and Expected

73

IN

74

Land Use, Tippecanoe County, IN

Tippecanoe County, IN

Order of model operation

75

109

5.2 District System, Tippecanoe County,

5.3

72

Road System, Tippecanoe County, IN

4.4 Rail Lines

5.1

IN

IN

for simulating the

110

dynamics of interaction

between Land use and Transportation, Tippecanoe County, IN 5.4 Current and Expected

5.5 Point

Land Use, Tippecanoe County, IN

System Method, Tippecanoe County, IN

77 Ill

1

12

Page

Figure 5.6 Dempster-Shafer Theory, Tippecanoe County,

5.7 Policy Test

5 8

Changes

in

1,

IN

Tippecanoe County, IN

114

the road network by 2000, Tippecanoe County,

5.9 Policy Test 2, Tippecanoe County,

5.10 Policy Test

113

3,

IN

IN

115

116

Tippecanoe County, IN

117

5.11 Changes in the road network by 20 1 0, Tippecanoe County,

IN

118

A evidence

140

B.2 The probability assignment based on

B

140

B.3 The probability assignment based on

A and B

B.

1

The

probability assignment based

on

evidence

evidences

140

CHAPTER 1 INTRODUCTION

Recent

(CAAA)

of 1990 and

Surface Transportation Efficiency Act (ISTEA) of 1991

has placed

legislation in the

the Intermodal

form of the Clean Air Act Amendments

increased emphasis on the use of travel

The

planning analysis.

CAAA

demand simulation models

demands

in

environmental and

that air quality forecasting

must consider the

interaction

between land use and transportation and requires regional land use

mitigating

congestion and

transportation plans to

quantify impacts on land use.

attainment areas need to indicate whether

impacts on

air

The ISTEA

environment impacts.

quality (Wegener,

1994).

new

policies for

long range

requires

For example,

MPOs

These groups believe

that current

non-

transport projects will have negative

The conventional

travel

demand

simulation

processes have, however, received strong criticism from environmental groups 1992).

in

modeling practice overstates the

(NARC,

air quality

emissions benefits of highway improvements by showing speed increases without the

induced

additional

(Hawthorn,

1991).

travel

that

may

result

improved

from

highway

infrastructure

This induced travel would be generated from trips previously

foregone, relocation of activities over a wider area, or

new growth

within the urban area

responding to the improved transportation system performance.

(Neuburger,

1971;

Putman, 1983,1991; Orski, 1989;Wachs, 1989; Mackett, 1993)

The

CAAA

of 1990 and the

ISTEA of

transportation programs and practices.

The

1991

CAAA

transportation planning and project development

Ambient Air Quality Standards programs

in

for

unquestionably will affect ongoing

of 1990 in

will

have a major impact on

areas not meeting the National

ozone and carbon monoxide. The federal-aid highway

those areas will be revised as a result of the

new

law's provisions for

sanctions, conformity, and transportation/air quality issues (Hawthorn, 1991).

of 1991 also in

will

place a greater emphasis on the use of travel

demand

highway

The ISTEA

simulation models

environmental and planning analysis. These two acts will have a profound effect on the

future of land use and transportation interactions.

One of

the most visible elements of public investment in recent decades has been the

enormous expenditures on new highway witnessed large-scale

shifts in population,

This same period

construction.

both from rural areas to urban areas, and within

the urban areas from city center to automobile-oriented suburban development. it

has proven

difficult to establish clear,

Although

complete, and explicit quantitative definitions of

the causal relationships between these developments, exist.

has also

it

is

clear that these relationships

(Putman, 1991; Mackett, 1993; Wegener, 1994; Giuliano, 1995; Waddell, 1995)

Land use covers

a variety of activities, including residing, working and shopping;

physical infrastructure such as workplaces and homes; and the outcomes of market

processes, such as property and land values.

changes

in transport.

Urban theory

also

All these activities can

shows us

be influenced by

that people locate their houses and

workplaces by trading off housing and commute costs and other factors schools, etc.).

Commuters choose

their residential locations

by considering both housing

needs and workplace access. Likewise, employers choose work

sites that are accessible to

employees with tolerable time and monetary costs (Giuliano, 1995). transportation planning requires a

urban

activities (land use).

Most

good

accomplished by predicting

often, this is

employment data

it

good

how

land use

Typically, the analyst will

for the study area, then allocate these area

totals to subareas, such as traffic analysis zones.

the area-wide control totals, but

Therefore,

forecast of the type, magnitude, and location of

patterns will change with respect to base year conditions. predict future population and

(e.g., amenities,

This allocation

is

must also conform to zoning

not only considered by restrictions

on type of

land use in each subarea and reflect the characteristics associated with each subarea that affect land use location decisions.

The

effects

of a change

living in an area

in

the level of activity

on the number of

improved transport

link

on the

trips

level

of



for example, the

made and activity



number of residents

the impact of a significant are observable

new

phenomena.

or

The

influence of changes in land use pattern on travel pattern tends to be easier to observe than

the converse relationship, because (a) travel patterns are affected primarily

by land use patterns, while

.

(b) land use choices are influenced

The

effects

by many

of land use on transport can be modeled

levels using well-established travel trip distribution,

modal

split,

and

demand modeling

traffic

one of which

factors, only

assignment.

and generally accepted way to model the converse

at

is

transportation.

both aggregate and disaggregate

techniques, such as trip generation,

There

is,

however, no

relationship.

common view

(Putman, 1983; Mackett,

1993)

To

address the above issues, the principal objective of this research

is

to develop an

improved integrated land-use/transportation model to represent the two-way relationships

between land use and transportation, subject

to the following constraints:

1

The requirements of the ISTEA of 1991 and the

2.

The

acquisition of a statewide license by Indiana

(INDOT) 3.

CAAA of 1990.

demand modeling software TRANPLAN.

for the travel

Metropolitan Planning integrated

model

Department of Transportation

Organizations

(MPOs) and

other

potential

users

of the

not have (or could not reasonably be expected to collect) land

will

use and economic data

in

a form or in the level of detail that land use models

previously-developed need as input.

Therefore,

it

may be

travel patterns resulting

necessary to create a feedback mechanism to account for

from changes

in the

development pattern and the converse.

mechanism, where a land use allocation step generation, trip distribution, modal

discussed in

more

detail in

Chapter

Chapter 2 contains the

split

3,

literature

and

is

new This

integrated with the usual four-step (trip

traffic

assignment) travel

demand model,

is

"Model Structure and Methodology".

review for this research project and identifies the

strengths and weaknesses of the current integrated Land-use/Transportation models.

Chapter 3 describes the overall structure of the integrated Land-use/Transportation

model developed and the methodologies adopted

in this research.

Chapter 4 describes data requirements and the process of analytical quantitative analysis.

Chapter

5

is

a case study from Tippecanoe County, Indiana.

Chapter 6 contains the conclusions and recommendations from suggestions for further research.

this research, as well as

.

CHAPTER 2 LITERATURE REVIEW

Conventional four-step travel demand models, whether aggregate or disaggregate, cannot adequately represent the long-term impacts of changes use/transport policies (Putman, 1983; Mackett, 1993).

approach

is

in transport

supply or land-

In land use planning, a

common

the Delphi process, which relies heavily on local planners or experts.

approach does not

explicitly identify the interaction

This

between land use and transportation

and does not systematically evaluate the impact of transportation on land use or the converse, because

The

it

is

based on judgment rather than analytical quantitative approaches.

application of land-use/transportation models has evolved over

ISTEA and

CAAA

the

have accelerated

this evolution.

use/transportation models can be grouped into

Wegener (1994) mentioned meaning least

that they

two

classified

and disaggregate.

land-use/transportation models must be operational,

that

(For a more detailed review of operational models, see Waddell,

Models based on Lowry-type model

DRAM/EMPAL (Putman,

HLFM II + (Horowitz,

1983,1991)

1993)

(Mackett, 1983)

POLIS

(Prastacos, 1986)

Models based on Input/Output economic model

MEPLAN (Echenique et al., TRANUS

(de

KIM (Kim,

la

of

using a modification of Waddell's classification

1995 and Wegener, 1994.)

LILT

set

at

operational land-use/transportation models in use today can be

into the following groups,

system (Waddell, 1995).

2.

types, aggregate

have been calibrated, implemented and used for policy analysis for

The major

ITLUP,

The

In general, the integrated land-

one metropolitan region. This excludes theoretical models presented only as a

equations.

1

two decades.

1990)

Barra, 1989)

1983,1990)

3.

Models based on Random

CATLAS 5-LUT

Utility/Discrete

Choice theory

(Anas, 1985)

(Martinez, 1992)

Hamerslag(1994) Waddell(1995)

4.

Models using microsimulation techniques

NBER-HUDS

(Kain, 1985)

MASTER (Mackett,

5.

1990)

IRPUD

(Wegener, 1986; Wegener

Models

integrated with GIS.

et al.,

1991)

CUFM(Landis, 1993) Batty (1992)

Models based on Lowry-type model

The Lowry-Garin model (Lowry,

1964; Garin, 1966), a spatial interaction approach,

has been applied to study a number of policy issues relevant to fast-growing regions.

These include new transportation changes inability

in

facilities,

increased

labor-force

zoning regulations. However, the analysis of transportation

and

participation, is

hampered by the

of the model to account for endogenous congestion and route choice, or to

provide a basis for measuring the value of benefits produced (Berechman, 1988; Putman, 1983,1995).

grounding 1995).

in

Furthermore,

the

spatial

interaction

approach lacked any appropriate

terms of economic theories of activity location (Wegener,

1

994; Waddell,

Hence, Cochrane (1975) developed a "location surplus" notion to provide

satisfactory theoretical underpinning for

Garin type model.

The

economic theories of activity location

in a

a

Lowry-

derivation indicates that the trips that provide the trip-maker with

the greatest net benefit are the ones chosen.

the multinomial logit model

(MNL)

Furthermore, Anas (1983) demonstrated that

derived from

random

utility

maximization

is,

at

an

equal level of aggregation, equivalent to the entropy and gravity models proposed by

Wilson (1967, 1970).

Although the basic Lowry model circles, variations

on

it

is

called

decades old and

continue to be used

model with widespread application

employment

is

ITLUP

in

not accepted in

newly-developed software packages.

in

(Integrated Transportation

A

Land-Use Package) (Harvey and

ITLUP combines two

land-use model and a transportation network model.

separate components: a

model

In a later project, the land use

revised by improving calibration techniques and by modifying the spatial-allocation

formulae (Putman, 1991 and 1996). submodels:

EMPAL

descriptions, and data

The

model component includes two major

land use

on the current location of employment and population, the

trends, transportation facility descriptions, and data

EMPAL's

business,

developers,

traffic

is

congestion and

and government

based on random

utility.

in

it

In order to

EMPAL

these calculated that will

demand

match the land

METROPELUS, limitations

is

sum of land used available

for

a procedure

the actual change in the

is

1994).

overcome ITLUP 's lack of

demand by household.

be used by each demand category. category, the

their

(LANCON)

to

modified to calculate location by employers,

calculation of location

demands and estimates

model

permits consistent treatment of

calculate land consumption.

DRAM's

DRAM

making decisions about

Putman (1995) incorporates

followed by

Taking regional

not realistically reflect the role of

the land market mechanism,

is

EMPAL

location and investment (Waddell,

a definite improvement because is

facility

on the current location of population,

ITLUP does

respective choice in development process:

However, ITLUP

several types.

forecast of the future location of employment, the

forecasts the future location of households.

household,

(Disaggregated

Beginning with regional trends, transportation

model forecasts the future location of employment of

along with

DRAM

(EMPloyment ALlocation model) and

Residential Allocation Model).

to

some research

the U.S. used to distribute residential population and

Deakin, 1993; Putman, 1974 and 1983).

was

is

LANCON takes both

amount of land, by zone,

After the calculations are done for each

adjusted, using an increase/decrease in densities,

such uses.

The new

release

of ITLUP,

one of the few successful urban models (Wegener, 1994).

of Lowry-type models, including

DRAM/EMPAL,

are:

called

Some

Workplace and housing

1)

they

may be jointly

determined (Waddell, 1995).

The models only consider

2)

choices.

assumed to be sequentially determined. Actually,

location are

They ignore

the

(or

demand

make

side

of

and employment location

residential

a crude representation of) the supply process of

housing and workplace choices.

The models do not

3)

simulate the dynamic process (e.g., the bidding action for house or

building) of changes in land prices or housing rents.

The models do not

4)

realistically reflect the role

of households, businesses, developers,

or governments in making decisions concerning the development process, for example, location choices and investment (Waddell, 1995).

The data 1)

required for

DRAM/EMPAL

3-5 household categories, defined

income groups) by zonal 2)

consist

Employment

is

level,

in

of the following items:

terms of income

whose parameters

whose parameters

3)

Total land area for each zone

4)

Vacant developable land

5)

The percentage of developable

6)

Ratio of the amount of household type n (n

7)

over the study

in the

for each

employment type k to the 1,2,..., 8)

retail,

are individually estimated.

in

the study area

land already developed for each zone.

total

=

1,2,..., 5)

number of employees

in

who

are employees in

employment type k (k =

area.

number of households over

in

employment type k (k =

1,2,..., 8) to

Amount of land

that can

9)

Amount of land

that can be used for

be used for residential development by zonal

employment type k (k =

level.

1,2,..., 8)

development

level.

O-D zone

10)

Impedance

1

A network consists of streets and intersections in the study area.

(e.g., travel

the total

the study area.

8)

1)

manufacturing and

study area.

zone

Ratio of the number of employees

by zonal

are individually estimated.

divided into 4-8 categories (for example,

other employment) by zonal level,

middle, and low

(e.g., high,

time or travel cost) between each

pair.

.

Another Lowry-Garin type model

Model

11+) (Horowitz,

is

called

HLFM

1993).

urban area owing to improvements

in the

HLFM 11+

(Highway Land-Use Forecasting

11+ helps identify developmental impacts in an

highway and

transit systems.

the Lowry-Garin land-use model by permitting constraints on the total

may be

HLFM 11+ extends amount of land

allocated to various activities, by allowing for the possibility for agglomeration in

services,

and by representing constraints on population and service employment

district.

The

Traffic/Land

procedures

traffic forecasting

Quick Response System

Use

for

II

in

HLFM

Windows (QRS

equilibrium (or stabilized

)

HLFM

II).

solution.

five

(e.g.

disadvantages

years,

years

ten

or

more).

in

any

11+ are identical to those of the

The

11+ can find a combined

stabilized condition

there are no variations in activity locations and transportation costs within the

period

that

However,

of other Lowry-derivative models noted

HLFM

earlier.

explanation of the stabilized situation between land use and

11+

A

means

that

same time

also

has

the

more complete

transportation

will

be

described in Chapter 3

The required data 1)

for

One household ,basic

HLFM 11+ consist of the following items: category in the study area. Employment

and service (or

retail)

employment, by zonal

is

divided into 2 categories

level.

2)

Ratio of population to the total number of employees over the study area.

3)

Ratio of the number of service employees to the total population over the study area.

4)

Ratio of the number of service employees to the total number of employees over the study area.

5)

Amount of land

that can

be used for

6)

Amount of land

that can

be used for service development by zonal

7)

Land

8)

Persons per dwelling

9)

Value of time.

10)

Impedance

1

A network consists of streets and intersections in the study area.

1)

residential

development by zonal

level.

level.

area required for each service employee. unit.

(e.g., travel

time or travel cost) between each

O-D zone

pair.

10

The LILT (Leeds

Integrated Land-use Transport) model (Mackett, 1983)

developed for application to the split

city

stages of conventional travel

of Leeds.

It

combines the

demand model with

modes of transport

(car, public transport

trip distribution

a land-use model based

type theory to locate housing and economic activity. three

was

originally

and mode

on Lowry-

The model was disaggregated by

and walk), three socioeconomic population

groups, and twelve industrial sectors (manufacturing, transport and communications,

LILT

construction and so on).

employment (or economic shop

trips

uses processes similar to

activity)

between zones. Trips

ITLUP

to allocate population and

and to calculate the journey-to-work and journey-to-

for other purposes are calculated after the distributions of

population and economic activity have been found, by applying trip-generation and attraction rates based

on the interzonal

use/transportation model.

It

cost.

The LILT model

it

an aggregate land-

is

cannot explicitly represent the links between decision

processes of individuals (for example, choice of transport mode, as

trip-

home

location) over time,

represents population and employment associated with a set of cross-section zonal decisions over time

data, without identifying the various changes to the individuals'

(Mackett, 1990).

The

Projective Optimization

Land Use Information System (POLIS) of the San

Francisco Region, developed by Prastacos for the Association of Bay Area Governments, is

a mathematical programming formulation of a Lowry-type model based on random

utility

same

POLIS

and the given location of basic employment (Prastacos, 1986). limitations as other

shares the

Lowry-type models.

Models based on Input/Output economic model

Two

well-known models based on Input/Output economic analysis are

(Echenique

et al.,

Partners, and

MEPLAN

1990; Hunt and Simmonds, 1993), developed by Marcial Echenique and

TRANUS

(de

la

Barra, 1989), developed by

modeling, these two models use Input/Output structure and linkages of

market and capture the

economic

effect

activities.

Tomas de

la

Barra.

In land use

economic techniques to capture the

They

reflect the

operation of the land

of transportation improvements on land

prices, land use

and

11

development more

realistically

Once

mechanism.

than Lowry-derivative models, which lack a land market

the equilibrium stage of a land use

model

reached,

is

MEPLAN

transforms the resulting flows of labor, service and goods into physical flows of person trips

conventional transport model to do the model

model and the

traffic

The

restraint.

change

MEPLAN

work, to shop, or to school) and goods movements.

(to

transport model

iterated until convergence, that

is

from one

iteration to the next.

of the transport model are fed back in

the next time period.

has been applied

more than

in

by a hierarchical multinomial

logit

assignment by a multi-path probabilistic approach under capacity

in transport costs

of activities

split

uses a

is,

The generating

until there is

no

costs (disutilities)

into the land use model, thus influencing the location

MEPLAN

the second successful urban model and

is

a dozen countries in the world, including Greater

London

(Wegener, 1994).

Furthermore,

Kim

(Kim, 1983 and 1990;

Rho and Kim, 1989) proposed

transportation-land use model incorporating goods

demand

endogenously determined together with

is

of production and resulting

network

is

given.

efficient

The model

is

KIM

which zonal

analysis,

travel

congestion costs, optimal amounts

of land uses, once the transportation

random

utility

programming

and bid-rent theory.

It is

worth

model determines a general equilibrium between transportation

and location based on the

demand with endogenous

link

in

integrated into a consistent mathematical

framework based on input/output noting that only the

densities

movements

a combined

strict

economic sense of equilibrium between supply and

prices (Wegener, 1994).

KIM's approach, however, does

model physical stock, such as workplace (non-residential building such as

not

factories,

shopping centers and so forth) and housing, and land use development.

Models based on Random

The

attractiveness

Utility/Discrete Choice theory

of a discrete choice framework based on random

has increased since the contributions of McFadden (1973) and (1975).

Analysis

utility

maximization

Domencich and McFadden

of mode choice can be done using the standard techniques of

multinomial probit, multinomial logit and nested logit models (Ben-Akiva and Lerman,

12

1985).

Logit and nested logit approaches have also been applied to the choice of

residential location (Martinez, residential location

1992a and 1992b), the joint choice of

travel

mode and

by Lerman (1977), McFadden (1978), and Anas (1981, 1982, 1985),

and the joint choice of

residential location,

workplace and housing tenure by Waddell

(1995).

The Chicago

Area

Use

Transportation/Land

System

Analysis

(CATLAS) was

developed by Anas (Anas and Duann, 1985) and was applied to Chicago.

economic urban simulation model

that

contains a

location and on rent

in transportation policies

mode

implementation

difficulties that

long-term forecasting. 1)

Some of its

The assumption

that

of workplace

unrealistic.

is

may

on

residential

travel

and location choice

an elegant approach, but

it

has

some

development for short-term and

limitations are described below.

workers choose

The model does not

is

limit its potential

their residential location

based on a prior choice

Actually, Waddell (1995) and Giuliano (1995) mentioned

that housing location and workplace

2)

It

prices,

can be viewed as a hybrid of the land

and land use models (following Alonso, (1964)) with the

model (following McFadden, (1973)).

an

designed to evaluate the

It is

on housing and land

CATLAS

choice patterns.

is

simultaneous equation system to

estimate housing and land values and achieve equilibrium.

impact of changes

CATLAS

deal with

may be jointly

employment

determined.

location.

Hence, the validity of the

predictions of land price impacts on changes in land use or transportation strategies will

be questionable. In general, households and businesses compete for location, and

businesses often outbid households for location where they compete (Waddell, 1995). 3)

The mathematical formulation of

the model

is

exceedingly complex, requiring that a

system of hundreds of simultaneous equations be solved for equilibrium.

The

approach creates a large computational burden. 4)

The model

is

estimated

implementation.

in

aggregate form because of the simultaneous equations in the

Further disaggregation would probably substitute a microsimulation

approach for the approach adopted within the

CATLAS.

The microsimulation

procedure would require the development of a different model (Waddell, 1995).

The 5-LUT (5-Stage Land-Use Transport) model Santiago de Chile (Martinez, 1992a).

demand model with

developed by Martinez for

is

Martinez extends the conventional four-step travel

a residential location choice (logit form) as the

The model

fifth level.

integrated the bid-rent theory and discrete-choice approach for residential location choice. It

also has

many of

the

model warrants further

A Dutch

same problems discussed with respect to

C ATLAS.

But

this

attention for potential extension and application.

approach uses a general-equilibrium model

that includes land use,

employment

and residential location, and highway and public transport networks (Hamerslag, 1993 and

The model

1994).

is

based on micro-economic theory under budget and time constraints.

how

The model

identifies

interaction

between transport

the dynamics of land use development are influenced by the infrastructure and land use development,

and provides

forecasting and sensitivity testing of policies for changes in highway and public transport

networks.

This

micro-economic

approach

offers

overcoming existing land-use/transportation model

the

greatest

limitations

opportunities

for

and may warrant further

research and investigation.

Models using microsimulation techniques Aggregate land-use/transportation models cannot the decision processes (housing choice, individuals over time.

For

mode

explicitly explain the links

between

choice, route choice and so forth) of

this reason, the application

of disaggregate microsimulation

approaches to land-use/transportation models becomes

attractive,

and

a

computing

approach based on microsimulation using a large sample of households becomes more efficient

The the

than one based on aggregate data (Waddell, 1995).

NBER

HUDS

(National Bureau of

Economic Research) model (Ingram

et al.,

1972) and

(Harvard Urban Development Simulation) model (Kain and Apgar, 1985) are

economic urban simulation models, which have been applied to policy questions concerning the housing market.

The

NBER-HUDS

models were developed to evaluate

the impacts of spatially housing improvement programs (Kain and Apgar, 1985).

NBER-HUDS

The

models employ a disequilibrium framework to obtain housing choices and

14

location rents within 50 distinct housing markets using a linear

One major weakness of

NBER-HUDS

the

models

is

programming approach.

the assignment of households to

housing units following the disequilibrium process rather than the better-established

market clearing procedures

in

CATLAS

(Anas and Duann, 1985).

The

NBER-HUDS

models, moreover, do not consider the interaction between transportation, land use and the housing markets

MASTER

(Micro- Analytical Simulation of Transport, Employment and Residence) has

been developed

in the

U.K. by Roger Mackett (1990).

It

was

developed

originally

because models such as LILT could not satisfactorily represent the complexity of responses to changes

in

developed by Wegener

at the Institute

(IRPUD) (Wegener,

Another microsimulation model was

the transport system.

Wegener

1986;

of Spatial Planning et

al.,

1991).

at

the University of

The IRPUD model

Dortmund

starts

aggregate data, but uses microsimulation approaches with endogenous sampling

housing market submodel.

with in its

The major shortcomings associated with the microsimulation

techniques are: (Waddell, 1995) 1)

Many

assumptions about individuals' decision processes must be made. This limits

its

credibility.

2)

The

errors involved in the aggregation of microsimulation

model behavior are not

easily identified.

3)

Disaggregation of key actors

computing

cost, although this

(e.g.,

households and businesses) produces a high

problem continues to diminish..

Models integrated with GIS Geographic Information Systems (GIS) are computer-based systems that are used to store and manipulate geographic information. essential tool for the effective use

1970s,

GIS has evolved

as a

This technology has been touted as an

of geographic information (Aronoff, 1989).

means of assembling and analyzing diverse

and Estes, 1990; Laurini and Thompson, 1994). ability to build

improves the

and maintain the

It

spatial data (Star

has greatly enhanced the planner's

spatial database for planning

ability to visualize the land

Since the

and

analysis.

GIS

also

use and transportation planning environments

at

15

the urban, regional, state, and national levels of government.

have started to developed

at

utilize

GIS

techniques.

the Institute of

California

Urban Futures Model (CUFM) was

Urban and Regional Development of the University of

California at Berkeley as a disaggregate first

The

Some new urban models

model of housing development, and

urban models to take advantage of GIS capabilities (Landis, 1993).

not a general purpose land use forecasting model, but benefits

from

integrating

(Waddell, 1995).

GIS

techniques

Another model using GIS

is

into

it

the

is

The

land-use/transportation

one developed by Batty (1992).

Their efforts are exploratory and simplistic

The model, however, does not transportation.

yet

CUFM

is

demonstrates significant potential

exploration, calibration, prediction, and the display of results from the urban entirely dealt with within GIS.

one of the

models

The data model are

at this stage.

consider the interaction between land use and

lt>

CHAPTER 3

MODEL STRUCTURE AND METHODOLOGY

3.1

Framework

Figure 3

.

1

shows the

model developed

in

this

overall

framework of an integrated Land-use/Transportation

research.

It

illustrates

The

forecasting and transportation system modeling. activities

of the markets for land use and transport.

area, the

model estimates the equilibrium housing

the

demand

the relationships between land integrated

use

model simulates the

For each zone within a metropolitan rents (or price of land) resulting

from

created by the activities in the zone and the supply of land or housing units (or

floorspace) at any one time.

In a similar

way, the model estimates the equilibrium

generalized cost of transport, including travel time and costs, that reflects the interaction

between the demand for (or accessibility)

is

travel

and the supply of transport

fed back to the land use

module

at

any time. The transport cost

in the

next time period, thereby

affecting the equilibrium rents of housing units or price of land and the location of activities.

The

integrated

of which

is

model allows comparison between two runs of the integrated model, one

a do-nothing case against which a policy can be tested.

to evaluate land use policies such as

new

industrial

The model can be used

or commercial construction and

transportation policies such as the improvement of the road network. period, the integrated stabilized situation

A

model

will

be iterated

between the land use

means

until

convergence, that

allocation

module and the

no

significant

population and employees over the study area

in the land

stabilized situation

significant

change

that there

is

change

is,

During each time

the model reaches a

travel in

demand module

the distribution of

use allocation module, and no

in transport costs (or travel time) in the travel

demand module from one

iteration to the next.

Figure 3.2 (Echenique

et al.,

land use and transportation.

1990) shows a dynamic process of interaction between In general,

the changes in the land use patterns will

17

Thus, the changes

immediately affect the distributions of travel patterns. activities (or trips

by purpose) resulting from the changes

demand module

as inputs in the travel

Changes

allocation module.

influence

the

accessibility)

spatial

produced

in the travel

module during the next time

The travel

integrated

of land

land use pattern will be used

same time period as

Therefore,

use.

demand module

for the land use

will

transport

the

be used

in the

disutility

(or

land use allocation

period.

model includes two major

demand module.

economic

network, however, will take a longer time to

in the travel

patterns

the

in

in

in

a land-use allocation

parts:

There are interface links (or modules)

module and

a

built to transform data

between these two modules

1)

The land-use

module:

allocation

employment location model,

contains

It

a

residential

a land use potential model,

model. The purpose of this module

is

location

2)

to estimate the spatial pattern

between zones before entering the

The

travel

travel

demand module: This module

for

home-based

estimating

and external-external

modes and then

assigns the vehicle trips

home-based

trips.

It

on the

splits

links

other,

was acquired by

The

TRANPLAN

of network being analyzed

as the basis for the travel

demand module

allocation module. allocation

It

It

on the routes and

Because

the Indiana Department of Transportation

interface module: This

travel

non-home-based,

the trip matrices into individual

considers the behavior of individual stochastic route choice.

3)

simultaneously

contains trip generation and trip distribution

includes capacity restraint on these links to represent congestion

study used

It

demand module.

school,

external-internal

license

of households (or

movement by work-to-home, home-to-shop and work-to-shop

trips

stages

an

and a land consumption

population), employment, and density of occupation and floorspace.

estimates the passenger

model,

a statewide

(INDOT),

this

demand module.

module converts the generalized costs produced from the

into the accessibility

between zones for use

in the land-use

operates in a reverse way, transforming output from the land-use

module such

as the flows of activities

between zones

into the physical flows

of person

trips, e.g.,

the peak-hour trip matrices by purpose, used in the travel

demand

module.

3.2

Land-Use Allocation Module

One major concern of interaction used

to

the land-use allocation

model should incorporate

economic

at least the

It

(3)

It

should reflect the changes

employment

Any such

activities in a region.

should help predict the impact of a change

location

in

employment opportunities

(e.g., a

upon the redistribution of population.

in accessibility to transportation services.

should recognize the importance of transportation costs and nontransportation

attributes (e.g.,

housing needs and neighborhood surrounding)

choice of household (4) It

analysis of spatial

the

following properties.

plant opening, expansion or closing) (2)

is

forecast the likely direction of population growth,

locations and the distribution of

(1) It

module

in

an individual's

site.

should obey population (or housing) and employment capacity constraints that are

either determined the natural

The

by fixing

residential

and employment densities or are affected by

topography of the region.

spatial interaction structure

of land-use allocation module

origins in entropy-maximizing theory (Wilson,

lacked an appropriate grounding 1995).

in

the

in this

its

1967 and 1970). However, Wilson's work

economic theories of

activity location

(Putman,

Consequently, a 'surplus' notion was developed by Cochrane (1975) to provide a

satisfactory theoretical basis for

gravity type model.

The

economic theory of

derivation of 'surplus'

is

activity location in a

explicitly discussed

Furthermore, Anas (1983) asserts that the multinomial logit model

random

research has

utility

maximization

is,

at

Lowry-Garin

by Cochrane (1975)

(MNL)

derived from

an equal level of aggregation, equivalent to the entropy

and gravity models proposed by Wilson.

19

The model developed

research uses a multivariate attractiveness function and a

in this

two-parameter travel deterrence function

Tanner's function, f(^

(i.e.,

=

) ;

A

analogous to Putman's (1995) equation forms. to

specific

satisfy

employment capacity and employment

strategies.

module includes two components: the

residential

exp(-/?/^.)),

consistent constraint procedure

population

including

constraints,

activity

a

f

The core of location

housing)

(or

is

used

capacity,

the land-use allocation

model and the employment

location model.

The

model

residential location

Following the 'surplus' concept proposed by Cochrane, a "location surplus" notion was developed by Putman (1995).

assumed

location model,

it

1995).

assumed

It

is

is

between the

difference

deterministic trip cost

that the

that

exponential in the upper

In order to derive the functional

tail

number of zones

the underlying

ur

distribution

trip.

The

cost

including direct travel payment and travel time cost and so on.

given as ^v probability

=

ja.

-

q

of the surplus

is

's',

given

all

is

approximately defined as the trip,

Therefore, the surplus

we



1) lag.

The amount of new housing constructed and

old stock demolished in a given time period depend on decisions

The land consumption model

in

CATLAS

(e.g.,

made

in last

time period

of a number of equations to

consists

simultaneously for each time period

work

or demolishing old ones

5 years).

These equations,

be

solved

similar to Anas'

(Anas and Duann 1985), are written as follows (equations (3.22)-

(3.30)).

n

I Q

E; wr

:

t,« ex P (-$"

tv )

1

where n

Q ;'=ZS, E?

(3.23)

n

k

=

&;

and and

ytf

=

(Lwrtf^(rp;t

ij

(3 - 24)

)r

X? X f ...X™

(325)

2

where the i

g;'

:

nJ

JJ

:

number of housing

units

of household type n

offered to those employees working in zone

the

number of housing

units

j

at

of household type n

(e.g., single-family) in

time period in

zone

i

at

time period

the probability that a housing unit of household type n in zone

i

at

J :

J :

t

J

be offered for renter occupancy, given the ongoing average rent ffl the probability that a housing unit of household type n in zone i at time period will

J^

t.

time period

will

JJ"

zone

t.

be offered for owner occupancy, given the ongoing average rent

fi£*.

the average monthly rent of housing units of household type n in zone

time period

t.

i

during

t

.

30

x:

a vector of the zone's characteristics related to the supply side, such as the age of

:

an existing housing

~jj

77

unit.

a set of empirically calibrated parameters on the supply side for renter occupancy.

:

a set of empirically calibrated parameters on the supply side for

:

owner

occupancy. :

J?**

time period

at

£

:

f

yn

:

ni :

number of employees

the

in

employment type k

the attractiveness of residential zone

"

,B

=

zone j

i

a

t,

are the attributes of zone

?

,

oc\,

X"

1

+

for population living in household type n at

i

and

households or housing

sr

in

number of households for household type n to employees in employment type k over the study area at time period t the disutility (travel time or travel cost or both) of travel between zone and j.

X?,XX?,...,X

B

who work

the ratio of the

time period

"

(e.g., retail)

t.

i,

such as vacant available land, the number of

units, the

average rent of housing units and so on.

al, ..., an. empirically calibrated parameters on the demand

side.

cr Dr

-i 0,3K

(3-34)

)

.

34

where J

J£"

:

the supply side zone characteristics of housing units of household type n in zone i

during time period

such as the location of the housing unit and the percentage

t,

of developed land. 77 Im

's

are the coefficients to be estimated.

Thus, the probabilities renter

and

JJ"''r

JJ"''o that

an existing housing unit

be offered for

will

occupancy and owner occupancy can be derived using the following two

approaches.

Linear regression method

1

UZ=T]

rfi

K^t

TJrM

m=l

u:: =

t] oo

j k; +

±

lom

m=\

and

XZ+g

(335)

xz+£

(336)

satisfy

uz + uz

+

=

uz

i

°

(3-37)

where

TV*

:

the probability that a housing unit of household type n in

zone

i

at

time period

t

J

be offered for renter occupancy, given the ongoing average rent fl£ the probability that a housing unit of household type n in zone i at time period

will

TV * 1

:

t

be offered for owner occupancy, given the ongoing average rent J£' the probability that a housing unit of household type n in zone i will remain

will

TV*

:

vacant at time period Tj

,77

,7]

nJ

7

p

and-p"- are

2)

Logit model

and

7]

random

,7]

t.

,

,

7]

are empirically estimated coefficients.

error terms.

Ul

UZ

=

(338)

Ul + U2 + U3

35

U2

+U2

Ul

+ U3

U3

UZ=

(

34 °)

Ul + U2 + U3 where

ui=exP (77r0 2r + E

Tlrm

X;D

77^+1 7M

B

m=l

U2=exp(

m=

l

Equations (3.38)-(3.40) comprise the multinomial 77

,77

,..,77

,77

,

and 77

,77

,..-,77

logit

model, where 77

,77

are empirically estimated coefficients

The housing stock adjustment submodel

The adjustments of housing stock

from one time period to the next

are performed

Only the construction of new dwellings on vacant land and the demolition of old dwellings

Anas (Anas and Duann, 1985) mentioned

are considered. crucially

on "present value of profit" (PVP)

Suppose the average

remaining lifetime.

average age

is

rental decision

q.

.

now

Then (time

(K,

that can

lifetime

-

depend

be calculated from a dwelling over

of a dwelling

the present value of profit,

t) until

that these decisions

in

(PVP)

,

zone

i

is

m years

and

its

its

can be obtained from a

the end of a dwelling's lifetime

MUOJl

+ U\,

)

+

(-

AfiuXi-

Ul U'J -

m

CPVP)

-

X

(3-41)

(1

+!)-«

36

If a dwelling can be constructed

on vacant land

in

zone

i,

then the profit accrued from

construction will be represented as follows.

RSji^r

A,,, =(PVP) ai +

C,

-

+

£u

(3-42)

where

RSim

l

(2it

the current construction cost for the dwelling in zone

'

p

random

a

:

the present value of situation will

A,„ = where \Z

is ;

(PVP)

.,,

in

all

be written

Vt,

+

=

profit,

^.

under

£

(

the land price and g.

is

a

random

equation (3 42) can be rewritten

+UI

r

error term.

The present value of

this

3

-

43 )

profit,

as:

(Mk, M\,uW\, -

)

r

+ U'.J

-

MU

m

Z

+

S=\

I

(3-44)

5=1

(1+r)^

The

The

as:

(& W\, ) ; ,,.

i.

be equal to the land price, which incorporates

future taxes and other expenses.

m

PVP

i.

error term

If the land remains vacant, the profit will

(

m years from now in zone

tne resa e value of a dwelling unit

differential profit

1

(1+r)

5

'

between the decision to construct a new dwelling versus keeping

the land vacant can be described as:

N

m

a,„

-

a,,, =

+ziz:;

x

m=

5=1

(1

+

rr

1

\

+

si

-

si

(3.45)

.

37

The term

V m=

Xtln stands for the second summation

_^

may

but these data

Thus

not always be available.

are used to represent these quantities. /L,---,/L

the above assumptions, the probability of a

vacant land

C

C/;-

in

in

equation (3 44) plus ~y.

,

\

zone

i

Under

are coefficients to be estimated

new

can be computed by a binary

a function of the supply side variables

dwelling that will be constructed on

logit

model.

T~

m

N



|_

5=1

m=l

_]

I

= m

N



l_

5=1

m=l

_|

(346)

I—

1

In a similar way, the probability of demolishing the average old dwelling in

be derived by a binary

logit

zone

i

can

model.

1

UT=

= L

(3-47)

J

m=1

*=a

where

y ,...,y

are empirically estimated coefficients.

Market clearing equilibrium during each time period

The equation

K2

^

•••>

i^']'

(3.22),

'

s

which

is

solved for the market clearing rent vector

J?"

=

tne core of land consumption model during each time period.

iff'

Anas

(1982) has demonstrated that the system of equations (equations (3.22)-(3.30)), given

Q



£

max y =

Ej^Ej

i

-

(i.e.,

constraint

to adjust values

of

find

Z

Ej^Ej

(3

-

68)

j

r ^ mm e < r mod.e

subject to J

employment location model would be run

^ 2 '-' and ^k to

solution for the

and yk (see equation (3.13)), within acceptable

can then be solved to satisfy the second goodness-of-fit criterion

(3.69)).

trip cost is



*s

< r ^ max e

(3.69) v '

where jj5"

:

p

:

£ max e C m0 d e r nun e

:

the observed employees working in zone

*-*

by the integrated model.

mean home-to-shop

trip cost.

the lower limit of mean home-to-shop r trip r cost.

Another goodness-of-fit calibration and Rubinfeld, 1991),

employees

j

the upper limit of mean home-to-shop trip cost. tne es timated

:

j.

the estimated employees working in zone

in

will

criterion,

RMSE

(root-mean-square error) (Pindyck

be used to compare the estimated and observed population and

the study area. In the residential location model,

RMSE w -JO/JV)2(i5-^)

3

where

RMSE

po/)

Pi

p N In the

:

:

:

:

the root-mean-square error for population.

the observed population living

in

the zone

the estimated population living in the zone the

number of zones

in the

employment location model,

study area.

i.

i

by the integrated model.

56

RMSE

frai

=

J(1/A0X (Ej-EjY

where

RMSE^

:

J?.

:

p

'

N

the root-mean-square error for employment. the observed employees working

the

:

in

the zone

i.

the estimated employees working in the zone

number of zones

in

i

by the integrated model.

the study area.

Gradient search method

The approach used models

is

to calibrate parameters in the residential and

gradient search technique (Bazaraa

to the nonlinear equations

et. al.,

1993).

employment location

This procedure

is

appropriate

of the two models, and to the non-normal distribution of the

data.

In the residential location model, equation (3.4) can be rewritten in the following

general form.

Z

=

Pi

Ej Bj

m

W tf t

(370)

ex P (-/? f ) f

and

where

p. J? f

the population living in zone

:

the

:

yy.

in

zone j

the disutility (travel time or travel cost or both) of travel between zone

:

.

i

number of employees working

:

B ,B

the residential attractiveness, such as vacant available land, the

households or dwelling

units, the

for population living in

zone

,

o.

:

The term employed

at

i

and

j.

number of

average monthly rent of housing

units,

i.

empirically calibrated parameters.

Q

2

Wi" t/

zone j

will

ex P(-/?

choose to

/, )

live in

represents the average probability of a

zone

i.

commuter

.

57

The of \y

model

calibration processes used in the residential location

B

equation (3.66)) with respect to the parameters

(i.e.,

,

maximize the value

to

B, and or

are derived using

the following steps.

Step

0: Initialization

Choose and Step

1:

set

the starting values for /?(t)

=

t

B(t) and

a(X), pick stopping tolerance £

>

0,

0.

Gradient

Compute function

By

,

the gradient, Vv)/(x(t))

Vj/(x(t))

=

v|/

(/?(t),

/?

(t),

= {dxfldB,

a(t)),

and

its

norm

the chain rule for the derivative, the gradient of

d\y

dp

d\\i

dyldB 1

1

,

dylda), of

V\j/(x(t))

1

1

with respect to

vj/

P

d P>

A

*fi

the likelihood

= t^{dy/ 1 ekjf

B

is

derived:

I ep

jfi

dp x

i

\

/ p,

-

z

S \EjBjA, \\Bj(L p

UAg)-t )

(3.72)

/

\

where

A

fi

'

Wi'tSa&rfij,)

In a similar way, the