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.

<div>Good wind-tunnel flow quality characteristics are vital to using test data in the aerodynamic design process. Spatially uniform velocity profiles are required to avoid yaw and roll moments that would not be present in real flight conditions. Low turbulence intensity levels are also important as several aerodynamic properties are functions of turbulence intensity. When measuring mean flow and turbulence properties, hot-wire anemometry offers good spatial resolution and high-frequency response with a fairly simple operation, and the ability to make near-wall measurements. Using hot-wire anemometry, flow quality experiments were conducted</div><div>in a closed-circuit wind tunnel with a test section that has a cross section area of 1.2 m x 1.8 m (4 ft. x 6 ft.). The experiments included measurements of flow velocity and turbulence intensity variation over the test section cross-section, spatial and temporal temperature variation, and</div><div>boundary layer measurements. The centerline velocity and turbulence intensity were also measured for flow speeds ranging from 13 to 43 m/s.</div>