Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 227-238). Available also in a digital version from Dissertation Abstracts.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

M.Ing. / The focus of this dissertation is on the evaluation of management in traffic safety, and how it is applied, using the Road Traffic Management Corporation (RTMC) as a case study. Road Traffic Management in South Africa is in a state of crisis. The constitution provides for concurrency with respect to road traffic management, however, no mechanism has been implemented for co-operation and coordination. It has been found that the current institutional arrangements are not conducive to co-ordination and rapid interventions. Due to the scarcity of resources and the desire to streamline the institutional arrangements, an innovative model has been developed which will perform road traffic management collectively, the Road Traffic Management Corporation, RTMC. The implementation of the RTMC will require full co-operation and acceptance by all the various departments concerned, from National Government level, through to Provincial levels, and the Local Authorities. Before the Corporation can be implemented, the funding needs to be secured, and the source of the funding must be stable and committed. The implementing of such a corporation will be delicate, and organizational structure needs to be clear to all parties. At this early stage of the RTMC, the methods of management already used by the RTMC need to be compared to proper management principles, to ensure that the RTMC will have the best structure to ensure its success. Any uncertainties or concerns that may exist among those involved at lower levels can be communicated to top-level management implementing the corporation. By conducting an independent, external investigation, any short falls can be identified which may have been over looked previously. This dissertation aims to ensure that the RTMC adheres to the relevant management principles, focussing on the objective of improving road safety. A questionnaire is devised for the National Department of Transport, so that an independent view of the vision of the RTMC can be acquired. The organizational structure proposed by the RTMC is examined and evaluated to determine the relationship, communication channels, functions and responsibilities, which are intended between the various levels of management and stakeholders. The funding of a corporation such as the RTMC is considered, as the source of such funds needs to be secured before the RTMC can be implemented. A preliminary budget prepared for the RTMC is compared to what funding has been made available. The main objective of the RTMC is to improve road safety. Therefore, the process it intends to use is evaluated to determine whether the goals it intends to achieve through this process are realistic. The engineering function required to improve road safety will also be evaluated in terms of what can be done by engineers to improve the safety on South African roads.

Indiana University-Purdue University Indianapolis (IUPUI) / Road accident reconstruction and simulation investigates the accident causes, suggests improvements in vehicle design and investigates failures in vehicle control and safety systems such as the anti-lock brake system (ABS) and air-bag deployment. This thesis focuses on analysis of crash data from vehicles not equipped with collision warning systems. Vehicle parameters before and during an accident can be recorded using an Event Data Recorder (EDR) which helps in reconstructing an accident. This tool, installed in the vehicle, records different crash parameters like vehicle speed, lateral and longitudinal acceleration, seat-belt status, and air-bag deployment over a period that spens the accident. This thesis focuses on accident reconstruction with and without EDR data. A simulation software tool called HVE is used to visually recreate the reconstructed accidents. HVE is a platform to execute different accident simulation methods which are used for specific types of simulations. Two such simulation methods, EDSMAC4 and EDHIS, are discussed in this thesis. The former is an important method for vehicle-to-vehicle collisions and the latter is used for analysis of human behavior involved in the accident. Three real-life accidents were chosen for reconstruction and simulation. They were Bus and Car accident, Three Vehicle accident and Intersection accident. These particular accidents were chosen to represent a diverse selection of accidents based on the following parameters: the locations of the accidents, the vehicles involved in each accident, and the data available. A qualitative analysis of vehicle occupant's behavior is also presented for one of the three accidents. The thesis discusses in detail the reconstruction of these three accidents. Throughout these simulations, the thesis illustrates the advantages and limitations of the EDR and HVE simulation software for accident reconstruction and simulation.

Traffic oscillations, or simply stop-and-go waves, are a common phenomenon arising in congested traffic but still not well understood. This phenomenon causes broad adverse impacts to safety risk, fuel efficiency and greenhouse emission. To eliminate or reduce those impacts, understanding the cause and propagation mechanism is essential. This dissertation studied driving behavior in traffic oscillations with the objective to uncover the formation and propagation mechanism of traffic oscillations. This study establishes a behavioral car-following model, the Asymmetric Behavioral model, based on empirical trajectory data that is able to reproduce the spontaneous formation and ensuing propagation of traffic oscillations in congested traffic. By analyzing individual drivers' car-following behavior throughout oscillation cycles it is found that this behavior is consistent across drivers and can be captured by a simple model. The statistical analysis of the model's parameters reveals that driver' behavior during oscillation (i.e., reaction to oscillation) is strongly correlated with driver behavior before oscillations and it varies with the development stage of the oscillation. Simulation of the model shows that it is able to produce characteristics of traffic oscillations consistently with empirical observations. This study also unveils the generation mechanism of the traffic hysteresis phenomenon arising in traffic oscillations using the Asymmetric Behavioral model. It is found that the occurrence of traffic hysteresis is closely correlated with driver behavior when experiencing traffic oscillations. In the growth and fully-developed stage of traffic oscillations, drivers behave differently, which results in different distribution of hysteresis patterns. This research makes it possible to unveil new management and control strategies of traffic oscillations to improve traffic operation and to quantify the environmental and safety impacts of traffic oscillations. For example, it can be used to estimate the increase of greenhouse emission and decrease of fuel efficiency imposed by traffic oscillations. It can also be used to study the increase of accident rate.

An intensive examination was conducted to test the credibility of current traffic signal change interval policies founded on a kinematic equation developed nearly 30 years ago. The investigation involved the review of relevant literature as well as an extensive collection of data. The literature review and data analysis revealed that current change interval policies rely on the disproven assumption that traffic decelerates at a constant rate. The data analysis also demonstrated that traffic approach speed and deceleration distance affect the manner in which deceleration occurs. Based on the data analysis, an alternative treatment of the kinematic equation is proposed using surrogate deceleration rates. The surrogate rates offer a pragmatic set of input for the kinematic equation. Therefore, rather than yielding a change interval based on an inaccurate assumption, agencies can implement change intervals which are responsive to local traffic.

published_or_final_version / Psychology / Master / Master of Philosophy

At most of the US signal, pedestrian walk timings run in concurrence with relevant vehicular traffic signal phases which means that major-street coordinated operations can be interrupted by a pedestrian call. Such interruption may increase delays and stops for major traffic flows. An alternative to this design is to increase the cycle length and embed pedestrian timings within the ring-barrier structure of the prevailing coordination plan. Both approaches have advantages and disadvantages. This study attempts a novel approach to address this situation by a comprehensive experimental evaluation of traffic performance under various pedestrian signal timing strategies. Findings show that either abovementioned approach works well for very low traffic demands. When the traffic demand increases findings cannot be generalized as they differ for major coordinated movements versus overall network performance. While coordinated movements prefer no interruption of the coordinated operations, the overall network performance is better in the other case. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Digitized by Kansas Correctional Industries

Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisor: Ardeshir Faghri, Dept. of Civil & Environmental Engineering Includes bibliographical references.