Thesis (Ph. D.)--School of Psychology, Georgia Institute of Technology, 2005. Directed by Gilard Chen. / Gilad Chen, Committee Chair ; Ruth Kanfer, Committee Member ; Jack Feldman, Committee Member ; Charles Parsons, Committee Member ; Henry Moon, Committee Member. Vita. Includes bibliographical references.

This research explored whether the effectiveness of leadership styles differs in safety-critical contexts compared to contexts where safety is less salient. The existing leadership literature lacks consideration of the context in which leadership takes place. Leadership styles that are valued and effective in one work context, might be less desired and less effective in another context. Using Bass’s (1985) transformational-transactional leadership framework, the present research argues that the extent to which safety is salient within a work environment, impacts on the effectiveness of transformational, transactional and passive leadership. Existing leadership research has focused on transformational leadership, but has paid little attention to transactional leadership. The present research argues that transactional leadership might be effective in safety-critical contexts, but might be less effective in contexts where safety is not salient. In work contexts, where employees are exposed to hazards and there is a high risk for injury, directive leadership practices, such as vigilantly monitoring performance and proactively correcting mistakes (i.e., transactional leadership), might be important for effective leadership. However, if safety is not salient within a work environment, then these leader behaviours might be less relevant. In addition, the research explored the competency of leader flexibility, which refers to leaders’ ability to adjust their behaviour to the requirements of a certain setting. Two questionnaire studies were conducted to investigate the research objectives. In both studies three aspects of safety salience were explored, i.e., level of hazard exposure, likelihood for injury and impact on safety of others. In study 1, the sample consisted of participants with leadership responsibilities who work in contexts with varying degrees of safety salience. Results showed that leaders’ perceived effectiveness of transformational-transactional leadership, and the frequency to which they adopt these two leadership styles, differed in dependence on the level of safety salience. Hazard exposure moderated the relationship between transactional leadership and safety incidents, indicating that transactional leadership is associated with lower incident rates if hazard exposure is high, but not if hazard exposure is low. Leader flexibility showed a significant relationship with leader self-efficacy and team performance whilst controlling for transformational-transactional leadership. In study 2, a two-source design was used where subordinates rated their leader’s behaviour and leaders rated their subordinates’ job and safety performance. The research was conducted in two host organisations; an oil and gas service provider and a food manufacturing company. Safety salience measures were investigated as team-level moderators. Results showed several cross-level interactions, which suggested that team-level safety salience impacts on the influence of transactional, transformational and passive leadership on safety and job performance. The research made an important contribution by merging the transformational-transactional leadership framework with contingency views of leadership (i.e., safety salience as a contextual attribute) and by considering leader flexibility as a leader trait in addition to leader behaviours.

The analysis of grade crossing safety has long focused on vehicle-train crashes using statistical models based on crash data. The potential crashes generated by vehicle-vehicle rear-end conflicts have often been ignored. The interaction of different traffic attributes on safety performance of a grade crossing is also not well-understood. The primary objective of this thesis is to model the causal relationship of vehicle-vehicle interactions by developing the operation logic of gate-equipped grade crossing using a commercially available microscopic simulation package that models human driver behaviors. The simulation-generated vehicle trajectory data allows detail safety performance analysis on vehicle-vehicle interaction over time as they approach the track. A dual-gate equipped crossing at Kitchener, Ontario is selected as the study area. Initially, logic modifications are made to the simulation package (VISSIM) in order to accurately model the grade crossing segment. A two-step calibration is used in this thesis. Firstly, model input parameters for a signalized intersection from literature are used to model typical car-following behavior along this type of roadway. Secondly, parameters used to model drivers’ decision and reaction when approaching crossing is fine tuned through data collection and calibration. After incorporating all the modifications to the simulation package, validation is undertaken by comparing model-generated speed profiles to on-site observed speed profile. The established model is tested for its safety performance sensitivity through varying three traffic attributes in the simulation: (i) percentage of bus, (ii) total traffic volume, (iii) percentage of cars in the center lane of a 2-lane approach. Four safety performance measures were selected. The overall results indicate that the established model is functional and reliable in modeling grade crossing vehicles interactions at gated crossings. In the absence of a train, vehicles’ reduction in speed in the vicinity of a crossing results in traffic flow turbulence that increases the opportunity for high risk rear-end vehicle interactions. The sensitivity test revealed that the spillback behavior of vehicles due to the stopping behaviors of buses increases risk in the upstream section. Also, overloading of vehicles into the network indeed improves safety as the effect of differential speed diminishes. Among the four selected safety performance measures, DRAC seems to reflect problems with rear-end vehicle interactions in the vicinity of a crossing as a function of the traffic attributes considered in this research.

Abstract The sustaining management of the enterprise is in addition to increasing productivities and promoting with product quality, should be also based on "Safety". Perfect and systematical management for safe hygiene cannot only improve the industrial safety performance, but also enhance the job-satisfaction. In fact, "person" is just root. Master of management Peter Drucker also point out:"The spirit of the company should be created out by leader". What influence does the different leadership style and effective safety management on the industrial safety performance exactly is the topic of this study. The purpose of this study aims to understand the leadership styles for high-ranking management of each enterprise, the differences under the different background variables, and explore the moderations of leadership style for high-ranking management of each enterprise between industrial safety system and industrial safety performance, job-satisfaction. The scope of the research regard the high-risk industries affirmed by the Industrial Development Bureaus such as steel manufacturing industry, petrochemical industry and chemical industry etc. in Kaohsiung area as the main inquisition object. The valid samples were 88 copies in the aggregate. (Including 30 business units) Through statistic analysis, the major results in the study were as follows: 1. There is a significant positive correlation between industrial safety system, benevolence leadership and the industrial safety performance. The authoritarianism leadership and cognition industrial safety performance have no significant correlation. 2. There is a significant positive correlation between benevolence leadership, industrial safety system and the job-satisfaction. The authoritarianism leadership and job-satisfaction have no significant correlation. 3. The interactive effects between the industrial safety system and benevolence leadership on the industrial safety performance are significant, that means the industrial safety system and the industrial safety performance don¡¦t reveal significant correlation under the interference of benevolence leadership. The benevolence leadership and the industrial safety performance reveal significant positive correlation. In other words, the higher degree benevolence leadership is, and the better industrial safety performance is. 4. The interactive effects between the industrial safety system and authoritarianism leadership on the job-satisfaction are significant, that means the industrial safety system and the job-satisfaction don¡¦t reveal significant correlation under the interference of authoritarianism leadership. The authoritarianism leadership and the job-satisfaction reveal significant negative correlation. In other words, the lower degree authoritarianism leadership is, and the higher job-satisfaction is. So, through the leadership style of the kindness and the management of the participate type, the high-ranking administrators cannot only improve the industrial safety performance effectively by adequate communication and encouragement, but also enhance the employee's job-satisfaction. On the contrary, through the authoritarianism leadership style, the rather strict management and the commending tone, based upon the conclusions of this study, the high-ranking administrators will not improve the industrial safety performance significantly, but reduce the employee's job-satisfactions. There was "authoritarianism " characteristic on most of the high-ranking administrators in the Taiwanese enterprises; they should establish the right leadership style on these grounds to promote organization performance successfully.

Abstract The main purpose of this study is to explore the perception of senior and vocational high school students regarding safety climate and safety performance in the campus. Based on the review of campus safety events, related literatures on campus safety, and the analysis of validity and reliability, a questionnaire was developed which includes 91-item campus safety climate (CSC) scale, 46-item campus safety performance (CSP) scale, 98-item campus safety event likelihood (CSEL) scale. The factor analysis of CSC located four factors including: school commitment and action, student's commitment and perception of risk, safety attitude, response during an emergency, which explain 38.67% of the total variance. And CSP scale results in four factors: safety organization and management, safety training, safety equipment and measures, maintenance and event investigation, which explain 59.85% of the total variance. The researcher distributed 3280 questionnaires to students in 41 senior and vocational high schools in Taiwan. Of these 41 schools, 21 schools were chosen because of their poor performance in campus safety while the other 20 schools were selected due to their bright performance in campus safety. And 2837 valid questionnaires have been returned. The retrieving rate of the questionnaires is 86.49%. The independent-sample T test, one-way ANOVA, Pearson correlation and canonical correlation analysis is has been applied to the analysis of the raw data. The major findings of the research are listed below: 1. Significant positive correlation between CSC and CSP is found. The strongest positive correlation exists between school commitment and action and CSP; the second one is between student's commitment and perception of risk and CSP. 2. School commitment and action is the best predictor to CSP, and the second one is student's commitment and perception of risk. 3. The more score a school gets in CSEL scale, the less campus safety events happened at that school. The significant positive correlation can be found among CSEL, CSC and CSP scale. And the correlation is especially high between CSEL and safety equipment and measure, the same is happened between CSEL and CSP. 4. The most frequent campus event among senior and vocational high school students is injures during exercises and games (26.3%). The next campus event is the conflicts between teachers and students (13.2%). The third one is traffic accidents outside the campus (12%). And the fourth one is the fights among teenagers (10.9%). 5. CSC, CSP and CSEL scales can provide available information for the control of campus safety event and for the direction of prevention campaigns. Keywords: campus safety climate, campus safety performance, campus safety perception

The analysis of grade crossing safety has long focused on vehicle-train crashes using statistical models based on crash data. The potential crashes generated by vehicle-vehicle rear-end conflicts have often been ignored. The interaction of different traffic attributes on safety performance of a grade crossing is also not well-understood. The primary objective of this thesis is to model the causal relationship of vehicle-vehicle interactions by developing the operation logic of gate-equipped grade crossing using a commercially available microscopic simulation package that models human driver behaviors. The simulation-generated vehicle trajectory data allows detail safety performance analysis on vehicle-vehicle interaction over time as they approach the track. A dual-gate equipped crossing at Kitchener, Ontario is selected as the study area. Initially, logic modifications are made to the simulation package (VISSIM) in order to accurately model the grade crossing segment. A two-step calibration is used in this thesis. Firstly, model input parameters for a signalized intersection from literature are used to model typical car-following behavior along this type of roadway. Secondly, parameters used to model drivers’ decision and reaction when approaching crossing is fine tuned through data collection and calibration. After incorporating all the modifications to the simulation package, validation is undertaken by comparing model-generated speed profiles to on-site observed speed profile. The established model is tested for its safety performance sensitivity through varying three traffic attributes in the simulation: (i) percentage of bus, (ii) total traffic volume, (iii) percentage of cars in the center lane of a 2-lane approach. Four safety performance measures were selected. The overall results indicate that the established model is functional and reliable in modeling grade crossing vehicles interactions at gated crossings. In the absence of a train, vehicles’ reduction in speed in the vicinity of a crossing results in traffic flow turbulence that increases the opportunity for high risk rear-end vehicle interactions. The sensitivity test revealed that the spillback behavior of vehicles due to the stopping behaviors of buses increases risk in the upstream section. Also, overloading of vehicles into the network indeed improves safety as the effect of differential speed diminishes. Among the four selected safety performance measures, DRAC seems to reflect problems with rear-end vehicle interactions in the vicinity of a crossing as a function of the traffic attributes considered in this research.

The present dissertation consists of two studies that combine personnel selection, safety performance, and job performance literatures to answer an important question: are safe workers better workers? Study 1 tested a predictive model of safety performance to examine personality characteristics (conscientiousness and agreeableness), and two novel behavioral constructs (safety orientation and safety judgment) as predictors of safety performance in a sample of forklift loaders/operators (N = 307). Analyses centered on investigating safety orientation as a proximal predictor and determinant of safety performance. Study 2 replicated Study 1 and explored the relationship between safety performance and job performance by testing an integrative model in a sample of machine operators and construction crewmembers (N = 323). Both Study 1 and Study 2 found conscientiousness, agreeableness, and safety orientation to be good predictors of safety performance. While both personality and safety orientation were positively related to safety performance, safety orientation proved to be a more proximal determinant of safety performance. Across studies, results surrounding safety judgment as a predictor of safety performance were inconclusive, suggesting possible issues with measurement of the construct. Study 2 found a strong relationship between safety performance and job performance. In addition, safety performance served as a mediator between predictors (conscientiousness, agreeableness and safety orientation) and job performance. Together these findings suggest that safe workers are indeed better workers, challenging previous viewpoints to the contrary. Further, results implicate the viability of personnel selection as means of promoting safety in organizations.

Doctor of Philosophy / Civil Engineering / Sunanda Dissanayake / Rural roads account for 90.3% of the 140,476 total centerline miles of roadways in Kansas. In recent years, rural fatal crashes have accounted for about 66% of all fatal crashes. The Highway Safety Manual (HSM) provides models and methodologies for analyzing the safety of various types of highways. Predictive methods in the HSM were developed based on national trends and data from few states throughout the United States. However, these methodologies are of limited use if they are not calibrated for individual jurisdictions or local conditions. The objective of this study was to analyze the HSM calibration procedures for rural multilane segments and intersections in Kansas. The HSM categorizes rural multilane segments as four-lane divided (4D) and four-lane undivided (4U) segments and rural multilane intersections as three-legged intersections with minor-road stop control (3ST), four-legged intersections with minor-road stop control (4ST), and four-leg signalized intersections (4SG). The number of predicted crashes at each segment was obtained according to the HSM calibration process. Results from calibration of rural segments indicated that the HSM overpredicts fatal and injury crashes by 50% and 65% and underpredicts total crashes by 48% and 64% on rural 4D and 4U segments, respectively. The HSM-given safety performance function (SPF) regression coefficients were then modified to capture variation in crash prediction. The adjusted models for 4D and 4U multilane segments indicated significant improvement in crash prediction for rural Kansas. Furthermore, Kansas-specific safety performance functions (SPF)s were developed following the HSM recommendations. In order to develop Kansas-specific SPF, Negative Binomial regression was applied to obtain the most suitable model. Several additional variables were considered and tested in the new SPFs, followed by model validation on various sets of locations. The Kansas-specific SPFs are capable of more accurately predicting total and fatal and injury crashes on multilane segments compared to the HSM and the modified HSM models. In addition to multilane segments, rural intersections on multilane highways were also calibrated according to the HSM methodology. Using crash modification factors for corresponding variables, SPFs were adjusted to obtain final predicted crash frequency at intersections. Obtained calibration factors indicated that the HSM is capable of predicting crashes at intersections at satisfactory level. Findings of this study can be used for improving safety of rural multilane highways.

In high- risk industries, such as aviation, safety is a key for organization survivor. Most accidents involve human losses and bring substantial cost to organizations. Accidents can devastate the reputation and profitability of any organization. In aviation, more than 80% of aircraft accidents are related to human errors. Safety culture has substantial impact on the success of any organization. Employees' performance and behaviors are influenced by their perception of safety culture within their organization. In the aviation industry, pilots are considered the last resort to prevent accidents or mishaps in the air or ground. The focus on pilots' perception of safety culture is vital to understand how the airline can influence pilots' behaviors in the flight deck, and provide opportunities to minimize risk or unsafe behavior in the future. The present study examined the effect of safety culture on safety performance among pilots of Saudi Airlines. Safety performance was measured by pilot attitude toward violations and pilot error behavior. The study further analyzed the mediating role of pilot commitment to the airline between safety culture and measures of safety performance. The study used a quantitative approach using survey questionnaire to collect the data. A total of 247 commercial airline pilots, captain and first officer, flying at Saudi Airlines voluntarily participated in the study. Confirmatory factor analysis was conducted to validate each latent construct. The study used structural equation modeling (SEM) to analyze the relationship between all variables in the study using AMOS 22 software. The study results revealed that safety culture had a direct effect on pilot attitude toward violations and indirect effect on pilot error behavior. Moreover, safety culture had strong effect on enhancing pilot commitment to the airline. The mediating role of pilot commitment to the airline was not significant, and could not mediate the relationship between safety culture and measures of safety performance. The present research contributed to the current state of knowledge about the significant role of safety culture as a main predictor of safety performance in civil aviation. The present study contributes to aviation psychology by analyzing the effect of safety culture as a predictor for improving pilot commitment to the airline. In addition, this research analyzed the effect of safety culture on pilot attitude toward violations and pilot error behavior. Study findings can be used by airline management to better identify causes of unsafe behavior inside the cockpit. The outcomes of this research emphasize the role of management in shaping and affecting employees' behaviors and attitudes.

The construction industry ranks high in the number of occupational incidents due to the complex and interdependent nature of the tasks. However, construction firms using lean construction have reported better safety performance than the rest. The situation reflects the limitation of traditional planning methods used in construction firms focusing on project level planning, at the expense of production level planning. Lean construction involves participants in the formal production planning process to minimize variability in workflow thus reducing probability of incidents. Considering the involvement of various participants in the production planning process, this research study hypothesized that communication levels afforded by participants during formal production planning have a positive impact on safety performance. The goal of this research study was to understand the role of communication in the formal production planning process and its impact on safety performance. A case study approach was adopted for analyzing two projects, one following formal production planning and another following traditional project planning. Weekly subcontractor coordination meeting was selected as the unit of analysis. Data has been collected using direct observations, open-ended interviews, and examination of archival documents. For this study, the independent variables were categories of communication and dependent variable was recordable incidence rate (safety performance). Communication data was analyzed using Robert Bales' Interaction Process Analysis. Based on the analyses, the participants involved in formal production planning demonstrated: more sensitivity and higher degree of control by frequently providing suggestions/opinions, more enthusiasm in exchange of commitments, sincerity by declining inquiry for commitments in case of conflict of interest, and greater involvement by engaging in frequent dialogues with others. In addition, participants involved in production planning adopted a proactive approach toward safety performance by ensuring that safety was considered while preparing production plans, thus helping improve awareness. The findings indicated a better safety record by the project following formal production planning in comparison to the other project. The research study provides a "meso" level understanding of the role of communication among project participants during formal production planning, and indicates that production planning might have a beneficial impact on safety performance. / Ph. D.