<p>This paper describes the development of simulation models for a variety of traffic flow scenarios. The major goal of the models was to evaluate the effects of driver characteristics and traffic composition on traffic flow. The five scenarios modeled and their respective objectives were as follows:</p> <p>1. Vehicles switching lanes to increase speed. Objectives were thruput and number of lane switches.</p> <p> 2. Vehicles merging into an adjacent lane. Objectives were distance traveled before merging and number of collisions during lane switching.</p> <p> 3. Vehicles switching from the left or right lane into the center lane. Objectives were number of collisions and number of new misses during lane switching.</p> <p> 4. Vehicles passing on a two-lane bidirectional road. Objective was number of collisions during passing. 5. Vehicles switching from the center lane to the left or right lane to avoid an impassible obstacle. Objectives were number of collisions during lane switching and number of collisions with obstacle.</p> <p> Various driver characteristics were implemented in the models. The concept of preoccupation/attentiveness was factored into the models through the use of varied reaction times. 0ther driver characteristics were incorporated in the models via the assignment of vehicle speed. The models provided for a wide variety of driver types. Examples are as follows:</p> <p> 1. Drivers in a hurry.</p> <p> 2. Tourists or drivers unfamiliar with the area.</p> <p> 3. Law-abiding drivers.</p> <p> 4. Aggressive and passive drivers.</p> <p> 5. Young, inexperienced drivers.</p> <p> 6. Tired truck drivers.</p> <p> The driver characteristics were varied via percentage allocations entered at run-time. The traffic composition for the models consisted of automobiles and multi-axle vehicles of fixed lengths. The percentages for each vehicle type were also entered at run-time.</p> <p> The scope and level of detail for each model was delineated with assumptions. General assumptions made included the following:</p> <p> 1. An autombile is 10 feet fong, a multi-axle vehicle is 30 feet long.</p> <p> 2. The width of a lane is such that only one vehicle can be accommodated at a time.</p> <p> 3. A vehicle is considered to be entirely in one lane or another.</p> <p> 4. A vehicle switches lanes instantaneously.</p> <p> 5. The reaction time of an attentive driver is normally distributed with a mean of .5; the reaction time of a preoccupied driver is normally distibuted with a mean of .7. Three standard deviations are included to ensure complete population coverage.</p> <p> 6. A collision between two vehicles results in the termination of the vehicle causing the collision: the other vehicle continues.</p> <p> Implementation of these models was performed using the student version of the simulation language GPSS/H. The models were validated. but not verified against their real world counterparts. Test results showed that select ctiver characteristics can affect traffic flow; however, the effect of traffic composition was relatively unshown.</p> / Master of Science

The recognition that employees and employers wield different levels of power in the workplace makes labour legislation a central part of the workplace. This is because the different levels of power possessed by the two parties impact not only on workplace decision making but also on the relationship between the two parties, thus, being the weaker party (worker), the importance of worker protection through legislation is very important. However, the extent to which all employees enjoy legislation protection has always been a bone of contention. The lack of employment security in certain sectors of the labour market is not always the direct consequence of a lack of labour legislation aimed at those sectors. Rather, factors such as supervising compliance and implementation of labour legislation are crucial towards achieving important goals of labour legislation such as job security and worker protection. This study attempts to understand the interplay between the nature of work, legislation and the impact on family and community life of taxi drivers, through studying the everyday work experience of local taxi operators. This study looks at the labour process of taxi driving in Mamelodi Township (Pretoria, Gauteng Province) and Jane Furse (Sekhukhune District, Limpopo Province). The study draws on post-Bravermanian labour process theory, work-life balance debates and labour geography for theoretical frameworks. This is an ethnographic study that mainly draws on the extended case method, supplemented with semi-structured interviews. Results indicate that taxi drivers work under harsh working conditions with very few employment-related benefits and little time for their families (social life). The drudgery of labour and the nature of the labour process motivate the need for taxi drivers to “make out”, as Michael Burawoy has described worker coping strategies. This involves what is termed binding, floating, sekero and rocky relations in this study. Findings also point out that current legislative stipulations, particularly the definition of a workplace, are incompatible with the nature of work characteristic of the minibus taxi industry. The study concludes that taxi drivers remain largely vulnerable and unprotected due to this mismatch between legislative stipulations and the nature of work in the industry. Related to the foregoing, the study concludes that the informality of the minibus taxi industry benefits to some degree both taxi drivers and taxi owners. The study also points out the fact that geography/space is critical to our understanding of certain industries and successful application of labour regulation laws. Finally the study concludes that different localities impact on the intensity and duration of the labour process(es) therefore negates the successful uniform application of labour laws. / Dissertation (MSocSci)--University of Pretoria, 2012. / Sociology / unrestricted

My thesis provides evidence supporting a theory asserting that the high level of competition that exists between motor carriers operating within long-haul trucking is the most significant factor contributing to the continuously high driver turnover rates affecting the entire logistics industry. I explore how long-haul truck drivers internalize the conflict between their identity and the aggressively competitive environment within which they work. Social science authors, industry reports, and truck driver feedback from my own ethnographic study are analyzed for contexts in order to explore the current operating definition of success for motor carriers in both monetary and human terms.

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The objective of the present study was to understand how the visual and mental processes work in tandem to affect the overall information processing capability of the individual, especially the older population, in a dynamic visual task such as driving. More specifically, our aim was to understand how the different parameters related to display of visual information in an in-vehicle display system and the age of the subject affect the information processing performance. The effects of stimulus distance, target size, display time, bits of information and the age group of the subject (young versus old) on the reading performance (information processing ability) under photopic and scotopic viewing conditions were thoroughly investigated in this study. Fifty-six individuals (28 young, 28 elderly) from the Montgomery County region were tested in the study in a mixed factorial repeated measures design with age as between subjects and the other independent variables as within subjects. The dependent variable was the reading score, i.e., the number of letters correctly identified. Results obtained from this study revealed that all of the independent variables had significant effects on the reading performance of the participants, except ambient illumination. Specifically, age has an important influence on the specific values of the design parameters. Also, these parameters interact among themselves so that one can be used to compensate for the other. These results can be used for developing the most relevant and optimal in-vehicle visual displays for the older population. / Master of Science

The objective of the study was to investigate multi-modality effects (visual and auditory) on the perception of urgency in elderly individuals addressing issues of safety and comfort. Twenty individuals (10 young, 10 elderly) from Montgomery County of Virginia participated in the laboratory study. In the pre-experimental audiometric tests, as expected elderly individuals had higher hearing thresholds (dBHL) than young across all the frequencies (250, 1000, 2000 and 4000 Hz) of pure tones. The difference was more pronounced at 4000 Hz. In visual acuity tests administered, elderly individuals had a lower Snellen VA than young at both near and far distances. The participants also were administered Bausch and Lomb color test; all participants were able to differentiate red color. Method of adjustment was used to collect empirical data. Rating test was administered after every treatment to objectively assess the participants' feeling of perceived urgency associated with the auditory warning signal. All the participants rated the experimental sound as urgent. Repeated measures was conducted to remove variations due to time and treatment conditions. A mixed-factorial design was used to investigate the main and interaction effects. The age effect was found to be marginally statistically significant. Modality and trial effects were not found to be significant. The reanalysis conducted after removal of outliers resulted in marginal statistical significance for age and modality main effects. Although not significant, a trend was seen in the pulse intensity levels (dBL) across modalities in the elderly individuals. Future research should be conducted to investigate modality effects in elderly individuals in a naturalistic driving environment which would give a better insight of the effects of dual modalities. / Master of Science

While other alternative project delivery methods have emerged to address the limitations of Design-Bid-Build, Design-Build-Finance (DBF) has surfaced more recently. Although DBF has gained prominence in the past decade, research pertaining to this method is limited. Consequently, this research investigated the use of DBF for the delivery of transportation infrastructure by five State DOTs: Florida, North Carolina, Georgia, Michigan and Texas through a combination of interviews with DOT personnel and investigation of completed or on-going DBF projects. To complement this, subject matter experts (SMEs) were interviewed to obtain a more general market perspective of DBF. As a result, two variants of DBF, DBF – Receivables and DBF – Risk Transfer, were identified; the DOTs investigated and the US more broadly, primarily use the DBF - Receivables variant where the contractor is entitled to payments for the activities completed irrespective of the project's completion. Whereas in the DBF – Risk Transfer variant, the contractor's payments are linked to the completion of the project. Further, DBF is employed on projects that are (i) in need of acceleration, which generates (ii) social and economic benefits such as congestion relief and safety enhancements; such projects are also (iii) subjected to short-term budgetary restrictions, but they typically have (iv) funds programmed in the future. The distinction found in the variants of DBF provides a better understanding of the drivers of DBF, which were validated through interviews. In practice, this distinction also aids public agencies in better identification of the appropriate project delivery method for a given project. / Master of Science / Infrastructure projects are complex with many stakeholders involved in different stages of the project lifecycle. Design-Bid-Build (DBB) is the conventional method of project delivery for government agencies in the United States for delivery of infrastructure in the in 20th century due to legislation like the Brooks Act of 1972. Alternative project delivery methods, which can be classified into Capital Delivery Methods like Design-Build (DB) and Lifecycle Approach Methods like Design-Build-Finance-Operate-Maintain (DBFOM), have recently re-emerged to overcome the shortcomings of DBB. Design-Build-Finance (DBF) is one such alternative delivery method that has been increasingly used in the past decade to aid public transportation agencies to meet growing infrastructure needs. Significant research has been conducted to determine the drivers of alternative delivery methods like DB and DBFOM. The potential benefits of DBFOM are not found in DBF since a contractor is not involved in the operations and maintenance stages of a project. Moreover, current literature on DBF is limited since it is a contemporary phenomenon. In the US, 11 transportation projects were identified that employed DBF in the past decade. To understand why public agencies are using DBF, this research examined DBF programs in five states using a mix of interviews of key stakeholders and a review of available project documentation. Two variants of DBF with different payment structures and risk profiles were uncovered. Further, agencies tend to employ DBF to accelerate the timeline of a project that has funds programmed in later years and to realize the associated social and economic benefits such as congestion relief or improved safety. However, agencies must consider potential disadvantages such as increased oversight and financing costs when deciding whether or not to use this method.

Thesis (PhD)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The problem of how the mind relates to the brain stands as one of the greatest challenges today. The materialistic worldview and pragmatic approach to social problems are both being transformed by discoveries of how human experience and culture arise in cerebral activity. Even so, this effort, spearheaded by neuroscience, has seen the important and contentious issue of driver behaviour somehow been left behind. From an extensive literature study, it can be concluded that gross disregard of the neural underpinnings of such behaviour tied to a behaviouristic approach is endemic to the field. Numerous qualitative psychological models (each associated with debates about their validity) and Artificial Intelligence models, which effectively only imitate robots 'impaired' to display some humanlike characteristics, were come across. Although neural networks are derived from current knowledge of computation within the brain and deployed in industry, human driver behaviour modelling is not benefiting from this revolution in humanlike information processing. To date, very little has been done to determine what makes road users speed, drive while drunk, overtake, or yield at crossroads. As the central nervous system is the human measuring device in and of the world and thus key affector of human behaviour, it is ofutrnost importance to invest resources in 'inoculating' the field of driver behaviour modelling onto a robust basis provided by neuroscience. Being a human driver incorporates a broad complement of interrelated brain systems to perform driving tasks (psychological functions) at hand, such as lane keeping, speed choice, risk perception, and obstacle avoidance. The proper level of analysis of such a psychological function is the level at which that function is represented in the brain. Providing a theoretical model of human behaviour, based on biological facts of the brain as a whole, is surely a challenge for decades to come, but the field of driver behaviour should be part of such an effort. Collaboration is needed among investigators from the fields of neuroscience, psychology, mathematics, computer science, and engineering to further driver behaviour modelling. It is uncommon that professionals from these fields have a thorough understanding of the other fields involved, but the author, not pretending to be an expert, argues that such a union of fields will be of significant value not only to transportation, but all behavioural sciences. The wealth of to-date knowledge amassed in neuroscience lies ready to be tapped by researchers interested in explaining human driver behaviour. To this end, the use of modem brain-imaging techniques will be invaluable in pinning down the neural correlates of particular driving subtasks, bearing in mind the extent of structural impacts on the brain of each individual, brought about by a lifetime of interaction with the environment. Thus, based on the findings of this literature study, the author proposes that supplementary work be conducted by a multi-disciplinary team to roll-out an experiment to study the nature of environmental stimuli as instigators of aggression and road rage, by drawing on knowledge about brain imaging and (amygdala) activation. / AFRIKAANSE OPSOMMING: Die vraagstuk hoe die verstand [denke] met die brein in verband staan, is een van die grootste uitdagings tans. Die materialistiese wêreldbeskouing sowel as die pragmatiese benadering van maatskaplike probleme word verander deur ontdekkings aangaande die wyse waarop menslike ervaring en kultuur hul in serebrale aktiwiteit voordoen. Desondanks is in hierdie poging, met die neurowetenskap aan die spits, die belangrike en omstrede kwessie van bestuurdersgedrag om een of ander rede agterweë gelaat. Uit 'n uitgebreide literatuurstudie kan afgelei word dat grootskaalse verontagsaming van die neurale basis van sodanige gedrag gekoppel aan 'n behavioristiese benadering endemies is aan die gebied. Talle kwalitatiewe sielkundige modelle en kunsmatige intelligensiemodelle is teëgekom, elk gepaard met debatte oor die geldigheid daarvan. Hoewel neurale netwerkmodelle gebaseer word op huidige kennis van verwerking binne die brein en ontplooi word in die industrie, trek menslike bestuurdersgedragmodellering nie voordeel uit hierdie revolusie in neurale inligtingsverwerking nie. Tot op hede is baie min gedoen om vas te stel waarom padgebruikers jaag, dronkbestuur, verbysteek of by kruispaaie toegee. Aangesien die sentrale senuweestelsel die menslike meettoestel in en van die wêreld is en dus die sleutelbeïnvloeder van menslike gedrag is, is dit van die uiterste belang om middele te investeer in die fundering van die gebied van bestuurdersgedragmodellering op 'n stewige basis daargestel deur die neurowetenskappe. Om'n menslike bestuurder te wees behels 'n omvattende komplement van verbandhoudende breinstelsels om bestuurstake (sielkundige funksies) te verrig, soos spoedkeuse, risikowaarneming en die vermyding van obstruksies. Die gepaste ontledingsvlak van so 'n sielkundige funksie is die vlak waarop daardie funksie in die brein verteenwoordig word. Die daarstelling van 'n teoretiese model van menslike gedrag, gebaseer op biologiese feite van die brein in die geheel, is gewis nog vir komende dekades 'n uitdaging, maar die gebied van bestuurdersgedrag moet deel uitmaak van so 'n pogmg. Samewerking is nodig tussen navorsers uit die neurowetenskappe, sielkunde, wiskunde, rekenaarwetenskap en ingenieurswese om bestuurdersgedragmodellering te bevorder. Dit is ongewoon dat vakkundiges uit hierdie velde 'n deeglike begrip het van die ander gebiede wat betrokke is, maar die outeur, sonder om voor te gee dat hy 'n deskundige is, betoog dat so 'n samesnoering van vakgebiede van betekenisvolle waarde sal wees, nie net vir die vervoerwese nie, maar ook vir al die gedragwetenskappe. Die omvang van die jongste kennis wat in die neurowetenskappe vergaar is, lê gereed om deur navorsers benut te word wat belang stel in die verklaring van menslike bestuurdersgedrag. Met dié doel sal die gebruik van moderne breinskanderingstegnieke van onskatbare waarde wees om die neurale korrelate van bepaalde bestuursubtake vas te pen, gedagtig aan die omvang van strukturele impakte op die brein van elke indiwidu teweeggebring deur 'n leeftyd van interaksie met die omgewing. Daarom, gebaseer op die bevindinge van hierdie literatuurstudie, stel die outeur voor dat addisionele werk gedoen word deur 'n multi-dissiplinêre span ten einde 'n eksperiment uit te voer, waarin die aard van stimuli uit die omgewing, wat lei tot padwoede, bestudeer kan word, met inagneming van die beskikbare kennis oor breinskandering en (amygdala) -aktiveringpatrone.