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The evaluation of freeway service quality is crucial work, and thus, transportation professionals have developed numerous measures including traffic volume, speed, and density. However, recent research efforts have indicated that such traditional measures may not fully reflect the quality of roadway service from the perspective of individual drivers, necessitating the development of alternative approaches that complement or replace the current service quality measures. As an alternative approach, the speed variation of a vehicle has been suggested as a promising indicator of traffic flow quality perceived by individual drivers. In particular, acceleration noise, defined by the standard deviation of the acceleration of a vehicle, has been often studied as a measure of the degree of speed variation. However, previous studies have been limited to the experimental level due to the difficulty in collecting high-resolution vehicle speed profiles for computing acceleration noise. In this dissertation, the characteristics of speed variation, measured by acceleration noise, are investigated using the rich set of GPS data collected from the instrumented vehicles driven by the participants of the Commute Atlanta research program. The employment of the real-world vehicle activity data, composed of every second of vehicle operation, renders this research effort unique and provides an opportunity to investigate the various aspects of acceleration noise in the real-world context. The investigation is performed by relating acceleration noise to its three influential factors: traffic conditions, roadway, and driver/vehicles. In addition, a fuzzy inference system-based methodology, combining vehicle speed and acceleration noise from instrumented vehicles, is proposed as an approach to evaluating traffic flow quality.

The Kinematic-wave model is one of the models proposed to simulate vehicular traffic. It has not received widespread use because of poor understanding of associated interface conditions and early use of incorrect numerical schemes used. This thesis analyzes mathematically correct boundary and interface conditions in the context of the Godunov method as the numerical scheme for the simulation software created. This thesis simulates a set of scenarios originally proposed by Ross, to verify the validity of simulation. The results of the simulation are compared against the corresponding results of Ross, and against intuitive expectation of the behavior of actual traffic under the scenarios. Our results tend either to agree with or improve upon those reported by Ross, who used alternate models.

The purpose of this research is to formulate a multi-commodity network flow model for vehicular traffic in a geographic area and develop a procedure for estimating traffic counts based on available partial traffic data for a selected subset of highway links. Due to the restriction of time and cost, traffic counts are not always observed for every highway link. Typically, about 50% of the links have traffic counts in urban highway networks. Also, it should be noted that the observed traffic counts are not free from random errors during the data collection process. As a result, an incoming flow into a highway node and an outgoing flow from the node do not usually match. They need to be adjusted to satisfy a flow conservation condition, which is one of the fundamental concepts in network flow analysis. In this dissertation, the multi-commodity link flows are estimated in a two-stage process. First, traffic flows of "empty" links, which have no observation data, are filled with deterministic user equilibrium traffic assignments. This user equilibrium assignment scheme assumes that travelers select their routes by their own interests without considering total cost of the system. The assignment also considers congestion effects by taking a link travel cost as a function of traffic volume on the link. As a result, the assignment problem has a nonlinear objective function and linear network constraints. The modified Frank-Wolfe algorithm, which is a type of conditional gradient method, is used to solve the assignment problem. The next step is to consider both of the observed traffic counts on selected links and the deterministic user equilibrium assignments on the group of remaining links to produce the final traffic count estimates by the generalized least squares optimization procedure. The generalized least squares optimization is conducted under a set of relevant constraints, including the flow conservation condition for all highway intersections.

Thesis (M.S.)--University of Tennessee, Knoxville, 2002. / Title from title page screen (viewed [Sept. 27, 2002). Thesis advisor: Wayne T. Davis. Document formatted into pages (142 p. : ill (some col.)). Vita. Includes bibliographical references (p. 46-47).

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Renatus N. Mussa, Florida State University, Dept. of Civil Engineering. Title and description from dissertation home page (viewed Mar. 8, 2004). Includes bibliographical references.

Thesis (M. Arch.)--University of Hong Kong, 1994. / Includes special study report entitled: Passenger movement in the ferry terminal. Includes bibliographical references.

Thesis (Ph. D. in Civil and Environmental Engineering)--University of California, Berkeley, 2003. / "Fall 2003." Includes bibliographical references (p. 131-136). Also available online at the ITS Berkeley web site (www.its.berkeley.edu/publications).

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