Civil & Environmental Engineering

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End date: 2009Subject: search.filters.subject.Urban and Regional Planning

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    ANALYSIS OF ACTIVITY CHOICE: THE ROLE OF ACTIVITY ATTRIBUTES AND INDIVIDUAL SCHEDULES
    (2009) Akar, Gulsah; Clifton, Kelly J; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Activity-based approaches have taken hold in transportation research over the last several decades. The foundation of the activity-based approach is to view travel as a result of our activity choices and scheduling decisions. Therefore, better understanding of activity choice, planning time horizons, and activity attributes will lead to more accurate demand forecasts. This dissertation extends the current activity choice modeling framework by incorporating the characteristics of the individuals' schedules, planning time horizons and focusing on the salient attributes of the activities. This study consists of three parts which are linked to one another by their conceptual and empirical findings. The first part identifies the determinants of the planning time horizons - defined as when people decide about performing their activities. Several household and individual characteristics, and activity attributes are tested for their association with planning times. The activity attributes which have significant impacts on the planning time horizons of the activities are used in the second part for generating new activity groups. The second part clusters activities based on their salient attributes, such as duration, frequency, number of involved people and flexibilities, rather than their functional types (work, leisure, household obligations, etc.) and creates activity groups such as "long, infrequent, personally committed activities", "quick, spatially fixed, temporally flexible activities" etc. The activity groups generated in this part inform the activity choice modeling structure developed in the third part. The main analytical techniques used in this research are the Principal Components Analysis (PCA) and discrete choice models. PCA is used to define the new activity groups. The analysis of the planning time horizons and activity choice are performed by mixed logit models. The model results reveal the significant relationships between socio-demographics, temporal characteristics, travel, and characteristics of the schedules on activity choice. The findings of these models could be integrated in the activity choice modules of the existing activity-travel simulation models by either applying the comprehensive model (which may face limitations due to the availability of data) or integrating the findings of the models in the decision rules.
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    An Agent-Based Model To Examine Housing Price, Household Location Choice, And Commuting Times In Knox County, Tennessee
    (2007-08-22) Mulbrandon, Matthew; Clifton, Kelly; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The research conducted for this thesis uses an agent-based model (ABM) to simulate housing price, location, and journey to work (JTW) times for households in Knox County, Tennessee. The model is a unique hybrid, combining analytic functions and agents that typically have been used separately for theoretical urban research in very simplified urban landscapes. At the same time it uses data from a real urban area to run and calibrate the model, which is common for statistically-based or gravity models. There are two goals for this simulation; first to examine the feasibility of this approach in urban modeling, second to test the effect of altering transportation times and preferences on agent behavior. Results show this approach can fit real data and represent urban processes reasonably well. In addition several interesting and surprising results are reported from model runs.
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    Multi-Criterion Dynamic Traffic Assignment Models and Algorithms for Road Pricing Applications with Heterogeneous Users
    (2007-06-05) Lu, Chung-Cheng Jason; Mahmassani, Hani S; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study develops a simulation-based dynamic traffic assignment, or dynamic user equilibrium (DUE), model for dynamic road pricing applications. This proposed model is considered as the bi-criterion DUE (BDUE) model, because it explicitly considers heterogeneous users with different values of time (VOT) choose paths that minimize the two path attributes: travel time and out-of-pocket cost. This study assumed trip-makers would select their respective least generalized cost paths, the generalized cost being the sum of travel cost and travel time weighted by the trip-maker's VOT. The VOT is modeled as a continuous random variable distributed across all users in a network. The BDUE problem is formulated as an infinite dimensional variational inequality (VI), and solved by a column generation-based algorithmic framework which embeds (i) a parametric analysis (PAM) to obtain the VOT breakpoints which determine multiple user classes, and find the set of extreme non-dominated paths, (ii) a simulator to determine experienced travel times, and (iii) a multi-class path flow equilibrating scheme to update path assignments. The idea of finding and assigning heterogeneous trips to the set of extreme non-dominated paths is based on the assumption that in the disutility minimization path choice model with convex utility functions, all trips would choose only among the set of extreme non-dominated paths. Moreover, to circumvent the difficulty of storing the grand path set and assignment results for large-scale network applications, a vehicle-based implementation technique is proposed. This BDUE model is generalized to the multi-criterion DUE (MDUE) model, in which heterogeneous users with different VOT and values of reliability (VOR) make path choices so as to minimize their path travel cost, travel time, and travel time variability. Another important extension of the BDUE model is the multi-criterion simultaneous route and departure time user equilibrium (MSRDUE) model, which considers heterogeneous trip-makers with different VOT and values of schedule delay (VOSD) making simultaneous route and departure time choices so as to minimize their respective trip costs, defined as the sum of travel cost, travel time weighted by VOT, and schedule delay weighted by VOSD. The MSRDUE problem is also solved by the column generation-based algorithmic framework. The Sequential Parametric Analysis Method (SPAM) is developed to find the VOT and VOSD breakpoints that define multiple user classes, and determine the least trip cost alternative (a combination of departure time and path) for each user class.
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    MULTIOBJECTIVE OPTIMIZATION MODELS AND SOLUTION METHODS FOR PLANNING LAND DEVELOPMENT USING MINIMUM SPANNING TREES, LAGRANGIAN RELAXATION AND DECOMPOSITION TECHNIQUES
    (2005-08-04) Faria, Jose Alberto; Gabriel, Steven A; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The land development problem is presented as the optimization of a weighted average of the objectives of three or more stakeholders, subject to develop within bounds residential, industrial and commercial areas that meet governmental goals. The work is broken into three main sections. First, a mixed integer formulation of the problem is presented along with an algorithm based on decomposition techniques that numerically has proven to outperform other solution methods. Second, a quadratic mixed integer programming formulation is presented including a compactness measure as applied to land development. Finally, to prevent the proliferation of sprawl a new measure of compactness that involves the use of the minimum spanning tree is embedded into a mixed integer programming formulation. Despite the exponential number of variables and constraints required to define the minimum spanning tree, this problem was solved using a hybrid algorithm developed in this research.
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    TRIP GENERATION MODEL FOR PEDESTRIANS BASED ON NHTS 2001
    (2005-09-01) kim, nam seok; Clifton, Kelly J.; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Since non-motorized transportation has been excluded from the main stream of the general transportation planning, there is no standard technique for estimating non-motorized transportation demand. This thesis aims to develop a trip generation model for pedestrians. This research uses Poisson regression to model as walk trips can be regarded as event counts. The National Household Travel Survey (NHTS) 2001 is the primary source of data used, supplemented by MD Property View data. At the individual level, regression models for general walk trips and walk trips to work are estimated. Then, the walk trips to work are validated by Census data at the tract level. Finally, using that walk trips to work have similar tendency to total walk trips, this thesis estimates the number of total pedestrians a day for 506 tracts in Baltimore metropolitan region.
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    An Analysis of Pedestrian-Vehicular Crashes Near Public Schools in the City of Baltimore, Maryland
    (2005-05-04) Fults, Kandice Kreamer; Clifton, Kelly J; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In previous research, children have been shown to be involved in pedestrian-vehicular crashes in high numbers due to improper pedestrian behaviors. Little research has been conducted to examine the relationship between schools and pedestrian crashes. This study analyzes pedestrian-vehicular crashes in the City of Baltimore, Maryland to determine any relationships that may exist between crashes near public schools and the physical and social attributes of these schools. It was found that the presence of a driveway decreases crash occurrence and severity. A setback from the road will decrease crash occurrence but increase the severity of the crashes. The presence of off-street parking was shown to increase the severity of a crash, particularly for children ages 16-18. Recreational facilities are shown to increase the crash occurrence and severity of crashes. This study however, is limited as it does not include pedestrian demand data and the results should be interpreted as such.
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    Pedestrian-Vehicular Crashes: The Influence of Personal and Environmental Factors
    (2005-05-03) Burnier, Carolina Valdemarin; Clifton, Kelly J; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This thesis examines the relationship between land use and pedestrian-vehicle crashes. Analysis focuses on how the pedestrian crashes vary by personal characteristics (age, sex, condition, and severity of injury) and physical characteristics of the crash area (location type, population density, land use, pedestrian activity, and demand). The data for this study are pedestrian- vehicle crashes in Baltimore City, MD occurring between 2000 and 2002, supplied by the State of Maryland Motor Vehicle Accident Report. The results from the analysis suggest that in general, there are significant effects of land use on pedestrian crashes and, more importantly, pedestrian exposure. When controlling for demand, urban downtown areas with high population and roadway densities and good commercial accessibility are found to have negative relationships to pedestrian exposure. The results may justify the promoting of denser urban neighborhood designs and advocate the need to guide safety policy investments to these urban areas with high pedestrian activity.