Lec 15 LU, Part 1: Basics and simple LU models (ch6.1 & 2 (A), ch3.2-3.8 (C1) Get a general idea of urban planning theories (from rading p.333-342 (A) & p.60- 64 (C1)) Learn how personal accessibility is expressed in urban planning theories through an example (p.336(A) & p.67-70(C1)) Learn how to estimate trip generation rates and how they can be used in urban planning (from reading p.75-79(C1)) Know the purposes of using land-use models Learn the essence of land-use forecasting from the Hansen’s accessibility model
Transcript
Lec 15 LU, Part 1: Basics and simple LU models (ch6.1 & 2 (A), ch3.2-3.8 (C1)
Get a general idea of urban planning theories (from rading p.333-342 (A) & p.60-64 (C1))
Learn how personal accessibility is expressed in urban planning theories through an example (p.336(A) & p.67-70(C1))
Learn how to estimate trip generation rates and how they can be used in urban planning (from reading p.75-79(C1))
Know the purposes of using land-use models Learn the essence of land-use forecasting from
the Hansen’s accessibility model
Urban Planning Theory
“The theory of urban planning is concerned with defining and understanding the contents, practices, and processes of planning.”
The planner’s objective is not merely to describe the city and its components, but rather to propose ways in which they can be changed, hopefully for the better.
A few terms used in planning field
Comprehensive plan, or the master or general plan: An official statement of a geographic unit’s policies and intentions.
Guidelines: A set of implementation techniques Legislation: Recommendations turned into bills and enacted into
law Codes: Housing and building codes, for instance. Important
implementation techniques for ensuring the quality of community growth. Establish standards. Used at the local municipal level.
Zoning: Legal device for implementing local land-use plans. Ensures compatibility and controls the densities of certain parts of the community e.g. residential, commercial, industrial zoning
Subdivision regulations: Regulations that complement the local zoning ordinances. Control the development and change occurring within a community
Infrastructure: the life-support facilities of a geographic unit, like, streets, bridges, sewers, rails, etc.
Provo? Visit: www.provo.org then, Citizen Information, then Planning/Building/Zoning, then General Plan.
Effects of zoning
Everybody wishes to maximize (benefits from) their locations. Locational preferences result in
patterns of concentration.
Land-use planners regulate the compatibility of land-use patterns through zoning (type of use) and other regulations (like height of buildings and size of lots)
All this effort is to ensure compatible land use. For instance, you do not want to have a bar near schools and residential areas.
The free-market sale may result in incompatible land use. (May? It will.)
Basic concepts for describing urban form and structure 1. Urban form: the spatial
pattern or “arrangement” of individual elements
2. Urban interaction: the collective set of interrelationships, linkages, and flows e.g. highways and streets
3. Urban spatial structure: Combines the urban form through the urban interaction with a set of organizational rules into a city system e.g., rent, density, income, etc.
Land use and transportation
Trip generation
Trip attractionTransportation system
Demand
Demand
Supply
Goal: to ensure balance between land use activity and transportation capability
Land use potential is a measure of the scale of socioeconomic activity that takes place on a given area of land Activities in a land “generate” traffic.
Trip generation provides the linkage between land use and travel
(See Example 5 on p.76 (C1))
A trip: an event linking an origin and a destination. It is performed by traveling on a defined route and a selected mode, and takes a certain time and cost to travel.
Land use for trip generation purposes is usually described in terms of land use intensity, character of the land use activities, and the location within the urban environment.
Accessibility
is the basic concept underlying the relationship between land use and transportation.
Accessibility refers to the ease of movement between places.
Accessibility increases when movement becomes less costly meaning people make trips more when trip costs are cheaper.
Accessibility is often measured by time and/or money.
See Examples 1 and 2 on pages 67 and 68 (C1).
These two examples show “accessibility” of one activity center to another in aggregated terms. Travel time is used for this comparison.
For instance Activity Center B is most attractive in relation to other centers A, C, and D because you have shortest travel times from B to all other centers.
Personal Accessibility
Personal accessibility is usually measured by counting the number of activity sites (opportunities) available at a given distance from the person’s home and factoring that number by the intervening distance. Accessibility measures can be calculated for specific types of opportunities, such as shopping or working (which also defines trip types).
j
bijji dOA
See p.69 for the definitions of variables.
Ai is the number of potential destinations available to a person and how easily he or she can reach them. You may replace a “person” with a “zone”; then, Ai is the accessibility of zone i.
See example 3 on page 69 (C1).
Purpose of using land-use development models and their classification
Why land-use models are needed? Somehow we need to predict with some degree of precision the spatial organization of population and economic activity in the region. Otherwise you cannot set out plans for future infrastructure projects.
Heuristic, Mathematical
SimulationScenarios
e.g. www.envisionutah.org
e.g. UrbanSim
Examples in the book
Hansen’s accessibility model This model is designed to predict the location of
population (where people might live) based on the premise that employment is the predominant factor in determining location.
3 values are computed: accessibility index, development potential, and population allocated to a zone
Accessibility index, Aij: b
ij
jij d
EA
Zone iZone j
Employment zone
Residential zone
dij
Distance between zone i and j
b, an exponent needs to be determined
The overall accessibility index for zone i:
j
bij
ji d
EA
Hansen’s accessibility model (cont)
Development potential = (accessibility index) x (holding capacity)
iii HAD
Holding capacity = the amount of “vacant” land suitable and available for residential use. This is a factor in attracting future population to the zone in question. Note in Example 6, the “vacant” land means the entire area of a zone. However, it can be used just for vacant lands as you see in one of your homework problems.
