Browsing by Author "Patterson, Zachary"

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    Disaggregate models with aggregate data: Two UrbanSim applications
    (Journal of Transport and Land Use, 2010) Patterson, Zachary; Kryvobokov, Marko; Marchal, Fabrice; Bierlaire, Michel
    UrbanSim has significant data requirements. In particular, it requires disaggregate data (traditionally at the 150 meter by 150 meter gridcell level) for employment, households, and buildings. While such data are not always easily available, most regions have readily available data in a more aggregate form, often at the level of traffic analysis zone (TAZ) or other municipal divisions. This paper describes two UrbanSim applications for the cities of Brussels, Belgium and Lyon, France that adopted different approaches of using aggregate data. In Brussels, aggregate zonal data were disaggregated to the gridcell level. In the Lyon application, the zone was used as the unit of analysis and as such, each zone corresponds to one gridcell. The objectives of this paper are: 1) establish whether an UrbanSim model can be developed using aggregate data; 2) describe two different approaches to using aggregate data with UrbanSim and evaluate; and 3) evaluate the advantages and disadvantages of using aggregate data, as well as the two different approaches described. In doing so, it advances knowledge in the field of transportation and land use modeling by helping modelers evaluate the use of an increasingly popular integrated transportation land use modeling option. Several conclusions flow from this work. First, aggregate data can be used to develop UrbanSim models. Second, only a limited amount of disaggregate information can be drawn from aggregate data. In the context of UrbanSim, this is manifested in models with relatively few variables and dubious simulation results—in other words, while it is possible to develop an UrbanSim application with aggregate data, it should not be used for applied analysis. Finally, the development of such models can be a relatively low-cost exercise to gain familiarity with UrbanSim’s functioning and data requirements. As a result, it can also be seen as an important first step to developing or evaluating UrbanSim for application in a new region.
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    Effects of Avatar Hand-size Modifications on Size Judgments of Familiar and Abstract Objects in Virtual Reality
    (2019-06) Patterson, Zachary
    Many research studies have investigated spatial understanding within virtual envi- ronments, ranging from distance estimation, size judgments, and perception of scale. Eventually, this knowledge will help us to create virtual environments that better match our spatial abilities within natural environments. To further understand how people interpret the size of virtual objects, we present an experiment that utilizes a proprioceptive-based size estimation measure designed to elicit a three-dimensional judgment of an object’s size using a box-sizing task. Participants viewed both ab- stract and familiar objects presented within action-space in a virtual environment and were asked to make an axis-aligned box the same size as the object they previously observed. A between-subjects manipulation modified a participant’s avatar hand size to be either 80%, 100% or 120% of their measured hand size. Results indicate that the avatar hand size manipulation scales various factors of these size judgments in the three dimensions. Additionally, whether an object was abstract or a familiar size object produced distinctly different size judgments.
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    Evaluating the effects of land use and strategies for parking and transit supply on mode choice of downtown commuters
    (Journal of Transport and Land Use, 2012) Zahabi, Seyed Amir; Miranda-Moreno, Luis. F.; Patterson, Zachary; Barla, Philippe
    Metropolitan regions around the world are looking for sustainable strategies to reduce motor-vehicle traffic congestion, energy consumption, and emissions. These strategies include land-use policies as well as improvements to public transit services. This empirical work aims at studying the potential impact of land use (LU), public transit supply (PT), and parking pricing strategies on the mode choice of commuters living in the commuter rail line catchments in the Montreal (Canada) region. It makes use of an econometric modeling approach with both transportation mode choice and neighborhood type choice as simultaneous decisions, in order to take into account the endogeneity of these choices. The neighborhood choices are represented by neighborhood typologies derived from a cluster analysis using land use and transit supply indicators (population density, land use mix, and bus transit supply). As part of the outcomes of this study, the elasticities of mode choice with respect to commuter-transit fees, travel time reductions, and hourly parking costs are estimated. From the results, it is observed that a reduction of 10 percent in the transit fee or relative travel time would increase mode split by 10 percent and 3 percent respectively. The effect of age on both mode choice and neighborhood choice is also estimated. e individual and household structure factors associated with mode choice and/or residential neighborhood choice are also identified. Commuter age affects both outcomes. Income and gender affect mode choice while car ownership and the presence of children are linked to neighborhood choice.