LOWRY MODEL-LAND USE MODELLING

1. LOWRY MODEL
Presented by
K.SRIKANTH (15CE62R14)
SURYA KANT SAHDEO(15CE62R15)

2. What is a Land Use Model?
Land Use Models use economic theories and simplified
statistic methods to explain and estimate the layout of urban
land uses.
Land Use Model is quantitative method to predict future
changes in land use, socioeconomic and demographic data
based on economic theories and social behaviours.

4. Continued…
 To gain a better understanding of the behaviour of urban areas, several
operational transportation / land use models (TLUM) have been
developed.
 The reasons behind using TLUM are numerous, such as the ability to
forecast future urban patterns based on a set of economic assumptions
or to evaluate the potential impacts of legislations pertaining to
environmental standards.

6.  The Lowry model was one of the first transportation / land use model
developed in 1964 for the Pittsburgh region.
 It depicts well the relationships between transportation and land use.
 Its premises were expended by several other models, known as "Lowry-
type“ models.
 The activities which the model defines are population , service
employment and these activities correspond to residential, service and
industrial land uses

7.  1960s – Ira Lowry
 Spatial interaction model
 Modeling innovations
 Sub-regional forecasts were generated to control to regional totals
 Employment, population, and transportation were combined in one model
 Many variations and extension have been subsequently developed

8.  Basic or Export Sector
 Sell their goods and services to non-locals
 Exogenous (Determined outside the model)
 Non-basic or Residentiary or Retail Sector
 Sell their goods and services to locals
 Includes government – schools, etc.
 Endogenous (Determined by the model)
 Household Sector
 Size and residential location are endogenously
determined

10. Basic is given (exogenous)
Forecast is derived from regional projections
Retail sector
Size and location are determined by size and location of the
population
Household sector
Size is determined by employment opportunities (including
basic and non basic)
Location is determined by accessibility, particularly to
employment

11. Basic Sector
Demand for
Labor
Size of
Population
Demand for Non-
Basic
Distribution of basic jobs across
zones is given
Travel time (network) is given
Model generates population and
non-basic employment by zone

12. Basic jobs by zone
Transportation network: travel times between every pair
of zones (generalized cost matrix)
Ratio of population to workers
Ratio of service (non-basic) workers to population
Friction factor (willingness to travel)
Location probability matrix
Provides the basis of residential location decisions based on
employment locations and travel times

13. 1) Basic job locations by zone (assumed)
2) Location probability matrix  residential zones of
basic workers
3) # workers per zone  population x zone
4) Population x zone  number of service jobs x zone
5) Location probability matrix  residential zones of
service sector workers

14. Lowry Model Structure
Basic Employment by
Zone - Exogenous
Residential Location
of Basic Employees
Population Associated with
Non-Basic Employees
Service Workers
(Non-Basic) by
Zone
Residential Location of
Non-Basic Employees
Population Associated
with Basic Employees
Service Workers
(Non-Basic) by
Zone
Residential Location of
Non-Basic Employees
Population Associated with
Non-Basic Employees
Converge to
Solution

15.  a) The core assumption of the Lowry model assumes that regional and
urban growth (or decline) is a function of the expansion (or contraction) of
the basic sector. This employment is in turn having impacts on the
employment of two other sectors, retail and residential.
 b) It is assumed that the location of basic industry is independent of the
location of residential areas and service centers.
 c) Population is allocated in proportion to the population potential of each
zone and service employment in proportion to market potential of each
zone.

16. Continued..
 d) The model ensures that populations located in any zones dose
not violate a maximum density or holding capacity constraint is
placed on each category of service employment.
 e) Lowry model relates population and employment at one
particular time horizon

18.  The model can be singly constrained, that is the only
constraint is the fixed location of basic employment.
 It can also be doubly constrained, where the location of
basic employment and housing are fixed

19. The singly constrained Lowry model is solved according to these Equations:

22. Continued..
 WTTRij and WTTSij = Willingness to travel for Residential (R)
or Services (S) between zone i and j.
 LPRij and LPSij = Locational probability for Residential (R) or
Services (S) between zone i and j.

23.  The Lowry model has obviously several limitations. It is notably a static model,
which does not tell anything about the evolution of the transportation / land use
system.
 the model is likely the be inaccurate in the major service-oriented metropolitan
areas of today where current economic changes are in the service (non-basic)
sectors, forming the foundation of urban productivity and dynamics in many
metropolitan areas.
 The Lowry model does not consider movements of freight in urban areas, which
are very significant and have impacts on the friction of distance

24. Every model has its strengths and limitations and no
model is best suited for every situation.
The selection of a land use model depends on
The purpose of the modelling.
Sensitivities to land use and transportation policies
Data requirements and availability
Modelling efforts (time, expertise and budget)

25.  The Lowry Model Heritage by William Goldner.
 Dr.Jean-Paul Rodrigue,The Geography of Transport Systems,chapter-9 Methods in
Transport Geography.
 David Levinson,Ira Lowry's LU Model.
 Website: http://en.wikibooks.org/wiki/Fundamentals_of_Transportation.
 Website: https://en.wikipedia.org/wiki/Land-use_forecasting#Lowry_model