This thesis addresses the problem of road intersection safety with regard to a mixed population of automated vehicles and non-automated road users. The work derives and evaluates safety-critical scenarios at road junctions, which can pose a particular safety problem involving automated cars. A simulation and evaluation framework for car-to-car accidents is presented and demonstrated, which allows examining the safety performance of automated driving systems within those scenarios. Given the recent advancements in automated driving functions, one of the main challenges is safe and efficient operation in complex traffic situations such as road junctions. There is a need for comprehensive testing, either in virtual testing environments or on real-world test tracks. Since it is unrealistic to cover all possible combinations of traffic situations and environment conditions, the challenge is to find the key driving situations to be evaluated at junctions. Against this background, a novel method to derive critical pre-crash scenarios from historical car accident data is presented. It employs k-medoids to cluster historical junction crash data into distinct partitions and then applies the association rules algorithm to each cluster to specify the driving scenarios in more detail. The dataset used consists of 1,056 junction crashes in the UK, which were exported from the in-depth On-the-Spot database. The study resulted in thirteen crash clusters for T-junctions, and six crash clusters for crossroads. Association rules revealed common crash characteristics, which were the basis for the scenario descriptions. As a follow-up to the scenario generation, the thesis further presents a novel, modular framework to transfer the derived collision scenarios to a sub-microscopic traffic simulation environment. The software CarMaker is used with MATLAB/Simulink to simulate realistic models of vehicles, sensors and road environments and is combined with an advanced Monte Carlo method to obtain a representative set of parameter combinations. The analysis of different safety performance indicators computed from the simulation outputs reveals collision and near-miss probabilities for selected scenarios. The usefulness and applicability of the simulation and evaluation framework is demonstrated for a selected junction scenario, where the safety performance of different in-vehicle collision avoidance systems is studied. The results show that the number of collisions and conflicts were reduced to a tenth when adding a crossing and turning assistant to a basic forward collision avoidance system. Due to its modular architecture, the presented framework can be adapted to the individual needs of future users and may be enhanced with customised simulation models. Ultimately, the thesis leads to more efficient workflows when virtually testing automated driving at intersections, as a complement to field operational tests on public roads.

Thesis (MPH. ) --University of Limpopo, 2014 / This dissertation reports on findings from a qualitative research that sought to investigate adherence and compliance to radiation safety protocols by radiographers and dental professionals in the Waterberg District. The study also sought to determine the knowledge the participants had on the chronic ill-effects of occupational exposure to radiation, safety protocols and their professional experience in dealing with occupational exposure to radiation. Altogether 60 participants from 8 health institutions in the Waterberg district took part in the study. They were compromised of males and females with ages ranging from 22-60 years. The response rate was 75% (n=45/60). The empirical data of the study shows a consistent yet disconcerting pattern among practitioners about safety compliance, safety protocols and their understanding of long term effect of occupational exposure to radiation. Despite their impressive knowledge of X-rays being a source of ionizing radiation, the level of their understanding of ill-effects thereof was of great concern. The general failure by both professionals in complying with the most basic safety protocols is worrisome. In a nutshell, yet some of the practitioners were found to be greatly exposed to radiation, their daily practices were found not consistent with procedures dictated by the guidelines on the use of medical X-ray equipment. Overall, only 59% of radiographers always wore their dosimeters, a basic monitoring and protective tool to measure their radiation exposure. In the study, only 38% of the dentists were found to be compliant and overwhelmingly alluded this to their employers being unable to supply them with crucial protective clothing, a finding that the researcher cannot dispute as indicated in the responses by the two groups. The failure of the employer in enforcing monitoring and assuring safety to the employees, patients and the general public emerged from this study. Various non-compliance patterns could be attributed to the participants and others to the employer. Protocols as clearly stipulated in R1332 of Hazardous Substance Act 15 of 1973 and other guidelines are not adhered to.

acase@tulane.edu / There are an estimated 48 million cases of foodborne illness per annum in the United States, with a majority of the illnesses associated with eating in a restaurant. Previous research into the causes of foodborne illness have primarily focused on factors that are internal to the restaurant. This research examines both internal components as well as external factors from the surrounding community that could influence how a food establishment operates. Inspection data, providing the basis for this analysis, came from routine inspection reports from Maricopa County, Arizona and the State of Florida. Additional evaluations are from randomly sampled restaurants, containing information on the occurrence of specific risk factors for foodborne illness, captured from States A and B. External community demographic data from the U.S. Census Bureau’s American Community Survey was also used. The routine inspection data was analyzed using a general estimating equations approach, and the risk factor study data was analyzed via a tobit regression. This approach allowed for the identification of the specific variables and their relative effect on the food safety performance of the establishment The only external factor to have an influence on restaurant food safety performance was the level of market competition, both near the restaurant and at a further distance from the restaurant. Other socio-demographic variables of the area were not found to have a significant effect. Internal factors, such as the level of food-handling and the food-safety related training held by employees were found to have an effect on the restaurants food safety performance. This study has shown the utility in assessing the compliance status of each risk factor, and the limitations of only using a count of violations. Additionally, concordant with most facilities operating in a sanitary manner, large sample sizes are required to identify an effect from a covariate. / 1 / Adam Kramer

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In Australia, the measurement of safety performance in the construction industry has mostly been in response to statutory requirements. Consequently, the measures and Key Performance Indicators (KPIs) used by the industry have invariably focused on outcomes rather than processes. Most of the outcome indicators have tended to give their feedback well after the event therefore failing to identify any weaknesses within the safety management processes. In order to overcome these limitations, two hospital construction projects in New South Wales were selected for an in-depth study and research analysis. The aim of the research was to understand the relationship between management process intervention and management process outcomes for safety in the construction industry. Initially a literature review identifying international practices in performance measurement for safety in construction was conducted so as to review existing safety management processes in partnership with the construction industry representatives. A framework for measuring the performance of safety management processes and related outcomes was developed to stimulate improvement on both projects through the comparison of the performance of the safety management systems and outcomes. This framework was then implemented and established to monitor the performance of the key safety management processes. The successful implementation of the performance measurement framework and the feedback to both stakeholders and subcontractors acted as a good communication tool in creating awareness among subcontractors. It also helped to reduce repetitive hazards, resulting in improved safety outcomes. A statistical analysis found that relatively few injuries were explained by the identified safety hazards. This highlighted the need to look for hazards that were specifically relate to injury occurrence. The research findings identified a method for improving the existing hazard identification process. It is anticipated that such improvements can help to better correlate hazard management processes with the project outcomes for safety in future projects.

The exposure to fumes and gases is one of the hazards associated with welding operations. Apart from research conducted on the mechanism of fume and gas formation and the relationship between fume formation rates and common welding parameters, little is known about the exposure process during welding. This research project aimed to identify the factors that influence exposure, develop an understanding of their role in the exposure process and through this understanding formulate strategies for the effective control of exposure during welding. To address these aims a literature review and an experimental program was conducted The literature review surveyed epidemiological, toxicological and exposure data. The experimental program involved three approaches, the first, an evaluation of the factors that influence exposure by assessing a metal inert gas/mild steel welding process in a workshop setting. The second approach involved the study of exposure in a controlled environment provided by a wind tunnel and simulated welding process. The final approach was to investigate workplace conditions through an assessment of exposure and control strategies in industry. The exposure to fumes and gases during welding is highly variable and frequently in excess of the health based exposure standards. Exposure is influenced by a number of a factors including the welding process, base material, arc time, electrode, arc current, arc voltage, arc length, electrode polarity, shield gas, wire-to-metal-work distance (metal inert gas), metal transfer mode, intensity of the UV radiation (ozone), the frequency of arc ignitions (ozone), thermal buoyancy generated by the arc process, ventilation (natural and mechanical), the welding environment, the position of the welder, the welders stance, helmet type, and helmet position. Exposure occurs as a result of three processes: the formation of contaminants at or around the arc region; their transport from the arc region, as influenced by the entry and thermal expansion of shield gases, the vigorous production of contaminants, thermal air currents produced by the heat of the arc process, and ventilation; and finally the entry of contaminants into the breathing zone of the welder, as influenced by the position of the welder, the welders stance, helmet type, and the helmet position. The control of exposure during welding can be achieved by several means: through the selection of welding parameters that generate low contaminant formation rates; through the limitation of arc time; and by isolating the breathing zone of the welder from the contaminant plume through the use of ventilation, welder position or the welding helmet as a physical barrier. Effective control is achieved by careful examination of the workplace, the selection of the most appropriate control option, and motivation of the workforce.

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The purpose of this study is to identify firm safety practices, safety technologies, and firm characteristics that are related to motor carrier accident rates. The theory of the firm suggests that firms maximize profit by investing in safety practices and safety technologies until marginal cost is equal to the marginal benefit. The data set used in the empirical analysis is unique, in that it will allow for testing of the relationship between firm safety performance and safety practices, new safety technologies, and firm marketing strategies. By testing the impact of the safety performance marketing strategy on carrier accident rates, it can be shown that firm managers have control over the safety performance of their firm through management decisions. The results indicate that firms with a safety performance marketing strategy have significantly lower accident rates. All tested technologies, and most safety practices, are found to be negatively related to carrier accident rates. These results support the idea that through investment policies, safety practices, and choice of marketing strategy managers have a direct impact on their carrier accident rate. Interestingly, the firm characteristics of unionization and use of owner-operators are found to reduce carrier accident rates the most. This suggests that motor carrier managers should consider their firm's characteristics in their management of carrier safety. / Graduation date: 2003

In roadway projects, design exceptions are implemented when the project site consists of one or more substandard design elements. The objective of this thesis is to conduct an initial investigation for a monitoring program for the safety performance of design exceptions in Georgia. A total of 467 projects containing design exceptions were reported in Georgia from 1995 to 2011, and from this crash data for 179 projects from 2003 to 2008 were sampled. The crash data collected in this research pertains to all roadway segments within the projects and is not necessarily related to the design exceptions. Future efforts will be required to explore potential connections between the crash rates and design exceptions. The annual crash results generally revealed a high variability and randomness in the data. For this reason, the average 3-year crash frequencies before design exception approval date and after it were calculated to determine the safety performance for projects containing design exceptions. A method for determining expected results using the Highway Safety Manual (HSM) predictive method is also discussed. The findings will be used to guide future research on design exceptions and mitigation measures to improve roadway safety.