Thesis (D.P.H.)--University of Michigan, 1996.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from PDF of title page (viewed Oct. 13, 2009). Additional advisors: Jerri D. Edwards, David L. Roth, David E. Vance, Virginia G. Wadley. Includes bibliographical references (p. 36-44).

The tractive force has to be interrupted during a gear-shifting operation in a manual vehicle transmission, leading into a decrease of speed while changing gears during the acceleration process. Therefore in a racing application, the shifting time has to be as short as possible so that the required performance of a racing car can be achieved. The following dissertation describes the development of a transmission control system to enable gear changes within a manual gearbox, which was designed for the Formula Student racing series. Various solutions were developed on the basis of reviewed literature, technical data of components and experiences of Formula Student teams. Following this, a comparison of the concepts by means of a utility analysis identified the pneumatic actuation of selector forks to be the most suitable concept. This was mainly due to the expected shifting time, the weight, and its advantageous energy supply requirement. After the selection of the actuators and the position sensors, the system was implemented into the drivetrain to check the tment and the technical feasibility. To draw conclusions regarding the shifting time and to prove the functionality of the system, an open test bench was constructed. Additionally, the hardware and software had to be developed to enable the test run. After the manufacturing and assembling of the test bench, the optimal settings for the test run were determined. By comparing the achieved shifting time of alternative solutions, an improvement in the driving performance of a Formula Student race car is probable.

xii, 69 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / New Urbanists promote development modeled upon neighborhoods that are highdensity and mixed-use with connected streets so that residents will drive less and have a strong sense of community. Little is known about whether New Urbanist environments provide the envisioned change in living experience for those who reside there. This study assesses changes in the living experience of residents of a suburban New Urbanist environment located in Eugene, Oregon, relative to their living experience in their previous residential environment. Findings reveal that respondents drive less for some but not all types of trips. There are no significant changes in sense of community. Changes in housing density and land-use mix are found associated with driving behavior change. Change in the enjoyment of the walking environment is found associated with changes in levels of resident interaction and feelings of sense of community. / Committee in Charge: Dr. Yizhao Yang, Chair; Dr. Robert Young; Robert Parker

Thesis (MTech (Industrial Design))--Cape Peninsula University of Technology, 2016. / Simulators are used for many different purposes, among them physical rehabilitation and the training of differently abled learner-drivers. In South Africa, however, the extent of the latter type of simulators is limited to paraplegic learner-drivers only. The reason is that locally sourcing the necessary equipment to adapt commercial simulators for the training of differently abled learner-drivers presents a problem. The concept of Universal Design stipulates that as many individuals as possible should be able to use a particular product. Consequently, a simulator for differently abled learner-drivers should accommodate as many such persons as possible. However, applying Universal Design in the area of design researched for the present dissertation adds further complexity due to the unique nature of the physical limitations experienced by individuals. A differently abled driver puts an extreme constraint on the design of a product - and becomes a limiting user. Nevertheless, this dissertation adopts a Universal Design approach to investigate the possibility of designing such a simulator in South Africa, as well as its viability. A limiting user was included in the research to represent the bigger differently abled community. Field research was carried out by implementing a Participatory Design process. Furthermore, a team was selected according to a Meta-Design mind-set, including professionals from engineering, clinical psychology and occupational therapy. The leader and researcher was an industrial designer.

Although a handful of experiments have utilized indirect feedback in attempts to reduce speeding on roadways, fewer experiments have utilized direct feedback as a means to reduce incidences of speeding. The current study evaluated the effects of direct and individualized feedback provided by a large electronic feedback sign that displayed the speed of oncoming vehicles as they approached the sign along the roadways of a college campus. The effects of the sign were evaluated using a non-simultaneous multiple baseline experimental design employing two control conditions and intervention phase. Each condition was implemented at three sites on the college campus. The results showed that intervention produced significant decreases in both measures of vehicle speeds at each site, relative to measures collected during both control conditions.

This study is concerned with the safety risk of reduced visibility on roadways. Inclement weather events such as fog/smoke (FS), heavy rain (HR), high winds, etc, do affect every road by impacting pavement conditions, vehicle performance, visibility distance, and drivers’ behavior. Moreover, they affect travel demand, traffic safety, and traffic flow characteristics. Visibility in particular is critical to the task of driving and reduction in visibility due FS or other weather events such as HR is a major factor that affects safety and proper traffic operation. A real-time measurement of visibility and understanding drivers’ responses, when the visibility falls below certain acceptable level, may be helpful in reducing the chances of visibility-related crashes. In this regard, one way to improve safety under reduced visibility conditions (i.e., reduce the risk of visibility related crashes) is to improve drivers’ behavior under such adverse weather conditions. Therefore, one of objectives of this research was to investigate the factors affecting drivers’ stated behavior in adverse visibility conditions, and examine whether drivers rely on and follow advisory or warning messages displayed on portable changeable message signs (CMS) and/or variable speed limit (VSL) signs in different visibility, traffic conditions, and on two types of roadways; freeways and two-lane roads. The data used for the analyses were obtained from a self-reported questionnaire survey carried out among 566 drivers in Central Florida, USA. Several categorical data analysis techniques such as conditional distribution, odds’ ratio, and Chi-Square tests were applied. In addition, two modeling approaches; bivariate and multivariate probit models were estimated. The results revealed that gender, age, road type, visibility condition, and familiarity with VSL signs were the significant factors affecting the likelihood of reducing speed following CMS/VSL instructions in reduced visibility conditions. Other objectives of this survey study were to determine the content of messages that iv would achieve the best perceived safety and drivers’ compliance and to examine the best way to improve safety during these adverse visibility conditions. The results indicated that "Caution-fog ahead-reduce speed" was the best message and using CMS and VSL signs together was the best way to improve safety during such inclement weather situations. In addition, this research aimed to thoroughly examine drivers’ responses under low visibility conditions and quantify the impacts and values of various factors found to be related to drivers’ compliance and drivers’ satisfaction with VSL and CMS instructions in different visibility and traffic conditions. To achieve these goals, Explanatory Factor Analysis (EFA) and Structural Equation Modeling (SEM) approaches were adopted. The results revealed that drivers’ satisfaction with VSL/CMS was the most significant factor that positively affected drivers’ compliance with advice or warning messages displayed on VSL/CMS signs under different fog conditions followed by driver factors. Moreover, it was found that roadway type affected drivers’ compliance to VSL instructions under medium and heavy fog conditions. Furthermore, drivers’ familiarity with VSL signs and driver factors were the significant factors affecting drivers’ satisfaction with VSL/CMS advice under reduced visibility conditions. Based on the findings of the survey-based study, several recommendations are suggested as guidelines to improve drivers’ behavior in such reduced visibility conditions by enhancing drivers’ compliance with VSL/CMS instructions. Underground loop detectors (LDs) are the most common freeway traffic surveillance technologies used for various intelligent transportation system (ITS) applications such as travel time estimation and crash detection. Recently, the emphasis in freeway management has been shifting towards using LDs data to develop real-time crash-risk assessment models. Numerous v studies have established statistical links between freeway crash risk and traffic flow characteristics. However, there is a lack of good understanding of the relationship between traffic flow variables (i.e. speed, volume and occupancy) and crashes that occur under reduced visibility (VR crashes). Thus, another objective of this research was to explore the occurrence of reduced visibility related (VR) crashes on freeways using real-time traffic surveillance data collected from loop detectors (LDs) and radar sensors. In addition, it examines the difference between VR crashes to those occurring at clear visibility conditions (CV crashes). To achieve these objectives, Random Forests (RF) and matched case-control logistic regression model were estimated. The results indicated that traffic flow variables leading to VR crashes are slightly different from those variables leading to CV crashes. It was found that, higher occupancy observed about half a mile between the nearest upstream and downstream stations increases the risk for both VR and CV crashes. Moreover, an increase of the average speed observed on the same half a mile increases the probability of VR crash. On the other hand, high speed variation coupled with lower average speed observed on the same half a mile increase the likelihood of CV crashes. Moreover, two issues that have not explicitly been addressed in prior studies are; (1) the possibility of predicting VR crashes using traffic data collected from the Automatic Vehicle Identification (AVI) sensors installed on Expressways and (2) which traffic data is advantageous for predicting VR crashes; LDs or AVIs. Thus, this research attempts to examine the relationships between VR crash risk and real-time traffic data collected from LDs installed on two Freeways in Central Florida (I-4 and I-95) and from AVI sensors installed on two vi Expressways (SR 408 and SR 417). Also, it investigates which data is better for predicting VR crashes. The approach adopted here involves developing Bayesian matched case-control logistic regression using the historical VR crashes, LDs and AVI data. Regarding models estimated based on LDs data, the average speed observed at the nearest downstream station along with the coefficient of variation in speed observed at the nearest upstream station, all at 5-10 minute prior to the crash time, were found to have significant effect on VR crash risk. However, for the model developed based on AVI data, the coefficient of variation in speed observed at the crash segment, at 5-10 minute prior to the crash time, affected the likelihood of VR crash occurrence. Argument concerning which traffic data (LDs or AVI) is better for predicting VR crashes is also provided and discussed.

This study was conducted in an attempt to improve drowsiness detection in automobiles by examining velocity-related measures. These measures were also included in multiple regression-generated drowsiness detection algorithms to determine their contribution to detection accuracy. In addition, the effects of cruise control and an auditory secondary task on the level of drowsiness and driving performance were examined. Twelve volunteers from the Blacksburg, Virginia area were used as subjects. In the early morning hours after sleep deprivation, subjects drove a moving base automobile simulator, during which time physiological and performance measures were gathered. Data analysis revealed that velocity-related measures can be good indicators of drowsiness when subjects are without external stimulation, but otherwise, these measures are fairly weak indicators of drowsiness. Similarly, the addition of velocity-related measures to drowsiness detection algorithms proved to be quite modest. Finally, there was no significant main effect of either cruise control or secondary task on drowsiness or driving performance. / M.S.

An investigation was conducted to determine the effects of driving time on nine continuous measures of driver performance and alertness, and to determine the extent to which such variables could be used to predict driver performance degradations in driving emergencies. Subjects were required to respond to one of three types of driving emergencies presented after each had driven continuously for periods of 30, 60 or 150 minutes (determined by random group assignment). The general findings of continuous measures indicated that in driving periods of 60 minutes and longer: (a) drivers exhibited linear increases in a tendency to cause the vehicle to drift laterally (within the lane boundaries) and yaw over time; (b) drivers exhibited significant linear increases in the number of large steering reversals, and significant decreases in the number of small steering reversals over time; and (c) drivers exhibited significant increases in heart beat interval standard deviation and in body movement frequency over time. In all driving duration conditions, drivers exhibited significant degradations in their ability to respond to emergencies relative to their baseline driving performance levels. However, the amount of degradation did not differ among duration conditions. Correlational relationships of continuous and emergency performance data, possible methodological problems of previous investigations (in light of present findings), effects of steering gain on continuous and emergency performance, and suggestions of possible future investigations were discussed. / Ph. D.

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