National Academies Press: OpenBook

Innovations in Travel Demand Modeling, Volume 2: Papers (2008)

Chapter: T57054 txt_066.pdf

« Previous: T57054 txt_065.pdf
Page 74
Suggested Citation:"T57054 txt_066.pdf." National Academies of Sciences, Engineering, and Medicine. 2008. Innovations in Travel Demand Modeling, Volume 2: Papers. Washington, DC: The National Academies Press. doi: 10.17226/13678.
×
Page 74

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

respectively. Three VOTT scenarios were designed to examine the impact of how VOTT may affect spatial allo- cation of residences. The low, medium, and high VOTTs for each of the five household types were assumed to be as follows: (a) low VOTTs of $1.40/h, $3.50/h, $5.30/h, $9.00/h, and $10.60/h; (b) medium VOTTs of $2.80/h, $7.00/h, $10.50/h, $18.00/h, and $21.30/h; and (c) high VOTTs of $5.50/h, $14.00/h, $21.00/h, $36.00/h, and $42.50/h, respectively. [The low, medium, and high VOTTs were taken to be 25%, 50%, and 100% of employed members’ wage (assuming one full- time employed person in the first four types of households and two full- time employed persons in the last type of house- hold.)] These households compete for homes that offer them the highest utilities. Due to this competition, home prices are bid up until the market reaches equilibrium. Essentially, individual households are assumed to evaluate all new (single- family) residential parcels as a function of their price, size, and site accessibility (in rela- tion to travel costs, distances to employment centers and shopping malls, or both). When a home is selected as the best choice by more than one household, the imbalance in both competition and supply–demand should increase the unit price. Following such price increases, the previ- ous best choice becomes unaffordable or at least less preferable due to the price increase, and other, relatively more preferred homes may emerge. Through this implicit price mechanism, households withdraw from competi- tion over home sites that are experiencing high demand. Ultimately, the model presumes that land developers sell the home or home site to the highest bidder at the mar- ket equilibrium’s highest price. Equilibration Results The market equilibrium for new home buyers (consider- ing 10% of the presently undeveloped land in Austin) was reached in an iterative fashion. The starting home value was assumed to be low, at just $100 per interior (built) square foot (or $25/ft2 of parcel land). Each house- hold was assumed to consider 20 randomly selected alter- native homes or home sites with specific sizes and accessibilities. IID Gumbel error terms were associated with each competing household and its set of considered alternatives. Knowing price and size, households were assumed to choose those offering the highest utilities as defined by the location choice model. Prices rose in steps of $1/ft2 when a home was desired by more than one household. When each household finally was aligned with a single, utility- maximizing home site, each occu- pied house was allocated to the household that tendered the highest bid. At this stage, the housing market (for new buyers–movers) is said to have reached equilibrium. In this way, Austin’s single- family residential development was simulated for each of six scenarios: the three sets of VOTTs for a study area having either a single employ- ment center [the central business district (CBD)] or multi- ple employment centers (with each of 114 such centers— housing at least 500 jobs— located within the study area in Year 2000). Figure 2 illustrates the locations of these employment centers, the CBD, and the locations of the 18 shopping centers as well. The new households’ working members were assumed to be allocated job sites according to the scenario (i.e., either all worked at the CBD or at sites nearest to their chosen homes). In each simulation, the average equilibrium unit price for each (large or subdivided) parcel was computed by averaging the unit prices of the occupied pieces that were subdivided from the parcel, and average occupant income was calculated as the average annual income of house- holds that chose to reside on the parcel. Figure 3 plots the average equilibrium unit price against the distance to the CBD or to the nearest employment center, depending on the scenario setup. As expected, the resulting plots illumi- nated how undeveloped parcels located near employment sites enjoyed higher average equilibrium unit prices. When VOTTs were low, there was no clear relationship between the average equilibrium unit price and the distance or travel time to employment sites. As VOTTs increased, the 66 INNOVATIONS IN TRAVEL DEMAND MODELING, VOLUME 2 FIGURE 2 Locations of Austin’s employment centers, cen- tral business district, and shopping centers.

Next: T57054 txt_067.pdf »
Innovations in Travel Demand Modeling, Volume 2: Papers Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 2: Papers includes the papers that were presented at a May 21-23, 2006, conference that examined advances in travel demand modeling, explored the opportunities and the challenges associated with the implementation of advanced travel models, and reviewed the skills and training necessary to apply new modeling techniques. TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 1: Session Summaries is available online.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!