Dissertations / Theses on the topic 'Safety performance level'

High speed facilities are considered the backbone of any successful transportation system; Interstates, freeways, and expressways carry the majority of daily trips on the transportation network. Although these types of roads are relatively considered the safest among other types of roads, they still experience many crashes, many of which are severe, which not only affect human lives but also can have tremendous economical and social impacts. These facts signify the necessity of enhancing the safety of these high speed facilities to ensure better and efficient operation. Safety problems could be assessed through several approaches that can help in mitigating the crash risk on long and short term basis. Therefore, the main focus of the research in this dissertation is to provide a framework of risk assessment to promote safety and enhance mobility on freeways and expressways. Multi-level Safety Performance Functions (SPFs) were developed at the aggregate level using historical crash data and the corresponding exposure and risk factors to identify and rank sites with promise (hot-spots). Additionally, SPFs were developed at the disaggregate level utilizing real-time weather data collected from meteorological stations located at the freeway section as well as traffic flow parameters collected from different detection systems such as Automatic Vehicle Identification (AVI) and Remote Traffic Microwave Sensors (RTMS). These disaggregate SPFs can identify real-time risks due to turbulent traffic conditions and their interactions with other risk factors. In this study, two main datasets were obtained from two different regions. Those datasets comprise historical crash data, roadway geometrical characteristics, aggregate weather and traffic parameters as well as real-time weather and traffic data. At the aggregate level, Bayesian hierarchical models with spatial and random effects were compared to Poisson models to examine the safety effects of roadway geometrics on crash occurrence along freeway sections that feature mountainous terrain and adverse weather. At the disaggregate level; a main framework of a proactive safety management system using traffic data collected from AVI and RTMS, real-time weather and geometrical characteristics was provided. Different statistical techniques were implemented. These techniques ranged from classical frequentist classification approaches to explain the relationship between an event (crash) occurring at a given time and a set of risk factors in real time to other more advanced models. Bayesian statistics with updating approach to update beliefs about the behavior of the parameter with prior knowledge in order to achieve more reliable estimation was implemented. Also a relatively recent and promising Machine Learning technique (Stochastic Gradient Boosting) was utilized to calibrate several models utilizing different datasets collected from mixed detection systems as well as real-time meteorological stations. The results from this study suggest that both levels of analyses are important, the aggregate level helps in providing good understanding of different safety problems, and developing policies and countermeasures to reduce the number of crashes in total. At the disaggregate level, real-time safety functions help toward more proactive traffic management system that will not only enhance the performance of the high speed facilities and the whole traffic network but also provide safer mobility for people and goods. In general, the proposed multi-level analyses are useful in providing roadway authorities with detailed information on where countermeasures must be implemented and when resources should be devoted. The study also proves that traffic data collected from different detection systems could be a useful asset that should be utilized appropriately not only to alleviate traffic congestion but also to mitigate increased safety risks. The overall proposed framework can maximize the benefit of the existing archived data for freeway authorities as well as for road users.
ID: 031988164; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references.
Ph.D.
Doctorate
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering

Evaluation of crash count data as a function of roadway characteristics allows Departments of Transportation to predict expected average crash risks in order to assist in identifying segments that could benefit from various treatments. Currently, the evaluation is performed using negative binomial regression, as a function of average annual daily traffic (AADT) and other variables. For this thesis, a crash study was carried out for the interstate, primary and secondary routes, in the Salem District of Virginia. The data used in the study included the following information obtained from Virginia Department of Transportation (VDOT) records: 2010 to 2012 crash data, 2010 to 2012 AADT, and horizontal radius of curvature (CV). Additionally, tire-pavement friction or skid resistance was measured using a continuous friction measurement, fixed-slip device called a Grip Tester. In keeping with the current practice, negative binomial regression was used to relate the crash data to the AADT, skid resistance and CV. To determine which of the variables to include in the final models, the Akaike Information Criterion (AIC) and Log-Likelihood Ratio Tests were performed. By mathematically combining the information acquired from the negative binomial regression models and the information contained in the crash counts, the parameters of each network's true average crash risks were empirically estimated using the Empirical Bayes (EB) approach. The new estimated average crash risks were then used to rank segments according to their empirically estimated crash risk and to prioritize segments according to their expected crash reduction if a friction treatment were applied.
Master of Science

Safety in the work place is a critical management issue and has serious dimensions in a petrochemical industry. Safety performance is closely linked with quality management. Quality being a competitive weapon has been the motivation for ISO 9001 certification. The primary objective of this research was to study and analyse the effect of ISO certification on the safety performance level of petrochemical industries in the Arabian Gulf region. The literature review revealed the gaps that exist in the research efforts until now relating to the effects of ISO 9001 certification on the safety performance in petrochemical companies. It also helped in identifying the 'instruments' for assessing safety performance more objectively. The reactive safety performance data before and after ISO certification was collected from 10 ISO certified Petrochemical companies. Proactive safety performance data was collected from the same 10 ISO certified companies as well as from another 10 non-ISO certified companies. The safety culture data was collected through questionnaire surveys conducted in these companies. Qualitative safety data obtained were quantified using conventional scaling techniques. Statistical analysis of the data showed significant improvement in safety performance level after the ISO certification. Results endorsed the view that positive safety culture is predominant in ISO certified companies. The research demonstrated the expediency of applying statistical models in analysing safety culture in Petrochemical industries. It is concluded that implementation of ISO 9001 significantly improved the safety performance in petrochemical industries in Arabian Gulf countries, and it can be assessed objectively through statistical techniques. Based on the findings of the research a revised ISO/TS29001 process model with 'safety at the centre' is suggested.

When a vehicle changes speed or direction, the interaction between the contacting surfaces of the tire and the pavement form frictional forces. The pavement's contribution to tire-pavement friction is referred to as skid resistance and is provided by pavement microtexture and macrotexture. The amount of skid resistance depreciates over time due to the polishing action of traffic, and for this reason, the skid resistance should be monitored with friction testing equipment. The equipment use one of four test methods to measure network-level friction: ASTM E 274 locked-wheel, ASTM E 2340 fixed-slip technique, ASTM E 1859 variable-slip technique, and sideways-force coefficient (SFC) technique. The fixed-slip, variable-slip, and SFC techniques are used in continuous friction measurement equipment (CFME). In the United States, skid resistance is traditionally measured with a locked-wheel skid trailer (LWST) equipped with either a ASTM E 501 ribbed or a ASTM E 524 smooth 'no tread' tire. Since the LWST fully-locks the test wheel to measure friction, it is only capable of spot testing tangent sections of roadway. By contrast, the remaining three test methods never lock their test wheels and, therefore, they can collect friction measurements continuously on all types of roadway, including curves and t-intersections. For this reason, highway agencies in the U.S. are interested in transitioning from using a LWST to using one of three continuous methods. This dissertation explores the use of continuous friction measurements, collected with a Sideways-force Coefficient Routine Investigation Machine (SCRIM), in a systemic highway safety management approach to reduce crashes that result in fatalities, injuries, and property damage only. The dissertation presents four manuscripts. In the first manuscript, orthogonal regression is used to develop models for converting between friction measurements with a SCRIM and LWST with both a ribbed and smooth tire. The results indicated that the LWST smooth tire measured friction with greater sensitivity to changes in macrotexture than the SCRIM and LWST ribbed tire. The SCRIM also had greater correlation to the LWST ribbed tire than the LWST smooth tire. The second investigation establishes the relationship between friction measured with a SCRIM and the risk of crashes on dry and wet pavement surfaces. The results of this showed that increasing friction decreases both dry and wet pavement crashes; however, friction was found to have greater impact in wet conditions. Due to the negative relationship between friction and crashes, eventually there will be a point where further losses in friction can result in a rapid increase in crash risk. This point can be identified with a friction threshold known as an investigatory level. When measured friction is at or below the investigatory level, an in- and out-of-field investigation is required to determine whether a countermeasure is necessary to improve safety. The third manuscript proposes a statistical regression approach for determining investigatory levels. Since this approach relies on statistical regression, the results are objective and should be the same for any analyst reviewing the same data. The investigatory levels can be used in a systemic approach that identifies locations where crashes can be reduced based on a benefit-cost analysis of surface treatments. Last, the forth manuscript demonstrates a benefit-cost analysis that selects surface treatments based on crash reductions predicted with continuous friction measurements.
Doctor of Philosophy
When a vehicle changes speed or direction, the tires slide over the pavement surface, creating friction that produces the traction that is necessary for the vehicle to change speed or direction. Friction can diminish when water, dust, and other contaminants are present, or over time due to traffic. Over time, the loss in friction causes the risk of a crash to increase. However, this relationship is non-linear, and therefore, eventually there will be a point where further losses in friction can cause a rapid increase in crash risk. For this reason, the pavement friction is monitored with equipment that slides a rubber tire with known properties over a pavement surface. Since friction is lowest when the pavement is wet, the equipment applies a film of water to the surface directly in front of the sliding tire. There are different types of equipment used to measure friction. The physical designs of the equipment and their method of testing may be different. For example, some devices measure friction by sliding a wheel that is angled away from the path of the vehicle, while others slide a wheel that is aligned with the vehicle but reduced in speed compared to the vehicle. The factors that make the equipment different can affect the quantity of friction that is measured, as well as the timing between each consecutive measurement. The advantages that some equipment offers can entice highway agencies to transition from a pre-existing system to a more advantageous system. Before transitioning, the measurements from the two types of equipment should be compared directly to determine their correlation. Statistical regression can also be used to develop models for converting the measurements from the new equipment to the units of the current, which can help engineers interpret the measurements, and to integrate them into an existing database. The presence of water on a pavement surface can result in a temporary loss of friction that can increase the risk of a crash beyond the normal, dry pavement state. This does not guarantee that dry pavements have sufficient friction as is suggested in most literature. In this dissertation, the relationship between friction and the risk of a crash on dry and wet pavements are evaluated together. The results show that increasing friction can decrease the crash risk on both dry and wet pavement surfaces. The amount of friction that is needed to maintain low crash risk is not the same for every section of road. Locations such as approaches to curves or intersections can increase the risk of a crash, and for that reason, some sections of roadway require more friction than others. Minimum levels of friction called investigatory levels can be established to trigger an in- and out-of-field investigation to determine whether improving friction can improve safety when the measured friction is at or below a specific value. This dissertation proposes a methodology for determining the investigatory levels of friction for different sections of roadway using a statistical regression approach. The investigatory levels are then used to identify locations where pavement surface treatments can reduce crashes based on a benefit-cost analysis. Last, the ability of a surface treatment to reduce crashes is evaluated using another statistical regression approach that predicts changes in crash risk using friction measurements. Since there are several treatment options, a treatment is selected based on estimated cost and benefit.

This master thesis examines the functional safety of the pressure sensor XMP i which is produced by BD SENSORS Company. The aim of this thesis is the demonstration of compliance of the pressure sensor XMP I with functional safety integrity level SIL3 requirements. The thesis is divided into three parts. The first part deals with the concept of functional safety, defines the basic concepts of functional safety, compares the approaches of functional safety according to selected standards and provides a general procedure for the functional safety determination. The second part deal with technical systems reliability defines reliability indicators and describes selected types of reliability analysis used in practice, especially the FMEA/FMECA analysis. Third part deals with the reliability analysis of the sensor XMP i and with evaluation of results.

In the late 1980s and early 1990s few transportation agencies around the world considered performance-based specifications as an alternative to improve the efficiency of the services provided to the public. These initiatives are better known as Performance-Based Road Maintenance (PBRM). PBRM calls for performance-based work, in which a desired outcome is specified rather than a material or method. This type of specification promises to be an excellent tool to improve government efficiency in maintaining transportation networks; however, without proper monitoring, it could likely yield adverse outcomes. Since PBRM is relatively new, the availability of reliable and comprehensive sets of guidelines to evaluate the effectiveness and efficiency of this type of specifications in the roadway maintenance arena is limited. Transportation agencies currently rely on criteria and procedures they have had developed from their traditional methods used to evaluate performance. Unfortunately, some of these procedures cannot appropriately assess the benefits, if any, accrued by the government as a result of implementing performance-based specifications for the maintenance of the roadway system. This research presents the development of a framework for monitoring PBRM more comprehensively and accurately. The framework considers the assessment of five main areas -- Level of Service Effectiveness, Cost-Efficiency, Timeliness of Response, Safety Procedures, and Quality of Services -- in order to guarantee the comprehensiveness and reliability of the evaluation process. The major contribution of this framework is to provide transportation agencies with guidelines for evaluating the effectiveness and efficiency of PBRM as an alternative delivery method to maintain and preserve the roadway system.
Ph. D.

The diploma thesis devotes to the process of ensuring functional safety of products in Bosch Rexroth Brno, which deals with industrial hydraulic systems. The first part introduces the basic legislative regulations concerning product safety and describes selected standards relevant to this thesis. The second part focuses on Bosch Rexroth and the current state in the field of ensuring functional safety of their products. It also includes a description of the functional safety solution of a specific project – a hydraulic try-out press. At the end of the thesis, improvements to the process of ensuring functional safety in response to the identified shortcomings are proposed.

Många arbetsrelaterade olyckor sker av att säkerhet kring att LOTO-principen är undermålig och att maskiners rörliga delar är lätt att komma åt. Vid konstruktion av en maskin är det viktigt att ta hänsyn till maskinens farliga upphov. För att konstruera bort detta är det viktigt redan på ett konstruktionsstadie att identifiera och bygga bort dessa områden med till exempel ett maskinskydd kring maskiner. Tillträdesplatser måste vara noga övervakad för att det ska vara en säker användning av maskin enligt maskindirektivet 2006/42/EG. I denna rapport har säkerhet såväl som kostnader setts över för en befintlig förreglingsbrytare på tillträdesplatser för en balningslinje och undersökt om kostnader kan minskas med föreslagen PROFInet baserat förreglingsbrytare. Den harmoniserade standarden EN ISO 13849-1:2016 tar upp ett sätt för att utvärdera säkerheten kring en maskins styrsystem allt utvärderas efter begreppet PL, Performance Level. För att räkna ut PL vid säkerhetsjämförelse användes SiSteMa och för att räkna ut kostnaden av dem olika alternativen emellan har en intervju kring kostnader gjorts och presenterats som en kvot. Säkerhetsjämförelse visar att PLd är bibehållen. Kostnadsjämförelsen visar att den föreslagna lösningen är dyrare än den befintliga men att en undermålig prisuppskattning kan ligga bakom detta. En aspekt av den nya förreglingsbrytaren som inte sågs över i rapporten men värt att nämna i slutsatsen kring säkerhets- och kostnadsjämförelse är att det föreslagna förreglingsbrytaren med PROFInet är en flexibel lösning med enkel felsökning. Framtida arbeten kring säkerhet vid balningslinje hade varit att titta på resterande tillträdesplatser som övervakas av ljusbomar och se om kostnader går att få ner där.
Many work-related accidents occur because safety around the LOTO principle is substandard and that the moving parts of machines are easy to access. When designing a machine, it is important to consider the machine's dangerous origin. To design this, it is important to identify and build these areas already at a design stage with, for example, a fence around machines. Access places must be carefully monitored for safe machine use according to the Machinery Directive 2006/42 / EC. In this report, safety as well as costs have been considered to an existing guard lock on access places for a baling line and examined whether costs can be reduced with the proposed PROFInet based guard lock. The harmonized standard EN ISO 13849-1: 2016 addresses one way of evaluating the safety of a machine's control system, all being evaluated according to the concept of PL, Performance Level. To calculate PL when comparing safety, SiSteMa was used and to calculate the cost of their different alternatives, an interview on costs has been made and presented as a quota. Safety comparison shows that PLd is retained. The cost comparison shows that the proposed solution is more expensive than the existing solution, but that a substandard price estimate may be behind this. One aspect of the new guard lock that was not seen in the report but worth mentioning in the conclusion about safety and cost comparison is that the proposed guard lock with PROFInet is a flexible solution with simple troubleshooting. Future work on safety at baling line would have been to look at remaining access places that are monitored by light curtains and see if costs can be reduced there.

The master thesis treats the design of control system of special purpose machine tool. The first part analyzes and compares two possible variants of control system which use either a CNC control system Sinumerik or motion control system Simotion. Only the variant with the Simotion control system is subsequently examined in detail: its hardware configuration, the selection of components and partly also the software solution. The thesis further deals with the safety of the realized control system and of the whole machine. There are described general safety requirements of machinery based on harmonized European standards and their specific application in the design of safety functions and the safety circuits of solved machine tool.

Les conditionneurs alternatifs – continu à absorption sinusoïdale (PFC) pour les applications critiques se distinguent par un haut niveau de performances tel que les THD réduits, un haut rendement et une bonne fiabilité. Leur importance est d’autant plus nécessaire qu’une continuité de service des alimentations est requise même en présence d’une défaillance interne de composant. Deux types de structures associées à leur commande sont réalisés à cet effet, les structures à redondance parallèle et les structure à redondance en série. Elles consistent respectivement en l’ajout d’un bras d’interrupteur dans le cas de la redondance parallèle, qui est une option plus compliquée et en une suppression d’une cellule de commutation dans le deuxième cas. L’étude présentée ici, consiste en premier lieu en une exploration et une évaluation de nouvelles familles de topologies multi-niveaux, caractérisée par un partitionnement cellulaire en série. Ces nouvelles topologies, ainsi que leurs variantes, comportent au moins une redondance structurelle avec des cellules mono-transistor à défaut de commande non critique et symétriques à point-milieu. Elles sont donc génériques pour la mise en parallèle et l’extension en triphasé. Cependant, elles sont pour la plupart peu compétitives à cause des composants qui sont souvent surdimensionnés et donc plus onéreuses, en comparaison avec la structure PFC Double-Boost 5 Niveaux à composants standards 600 V (brevetée par l’INPT – LAPLACE –CNRS en 2008) que nous étudions. Cette dernière constitue le meilleur compromis entre un bon rendement et une maîtrise des contraintes en mode dégradé. Sur le plan théorique nous montrons que le seul calcul de fiabilité basé uniquement sur un critère de premier défaut est inadapté pour décrire ce type de topologie. La prise en compte de la tolérance de panne est nécessaire et permet d'évaluer la fiabilité globale sur une panne effective (i.e. au second défaut). L'adaptation de modèles théoriques de fiabilité à taux de défaillance constant mais prenant en compte, au niveau de leurs paramètres, le report de contrainte en tension et l'augmentation de température qui résulte d'un premier défaut, permet de chiffrer en valeur relative, le gain obtenu sur un temps court. Ce résultat est compatible avec les systèmes embarqués et la maintenance conditionnelle. Un prototype monophasé de PFC double-boost 5 niveaux à commande entièrement numérique et à MLI optimisée reconfigurable en temps réelle a été réalisé afin de valider l’étude. Il permet une adaptation automatique de la topologie de 5 à 4 puis 3 niveaux par exemple. Ce prototype a également servi de test d'endurance aux transistors CoolMos et diodes SiC volontairement détruits dans des conditions d'énergie maîtrisée et reproductibles. D’autres campagnes d'endurance en modes dégradés ont été réalisées en laboratoire sur plusieurs centaines d’heures en utilisant ce même prototype. Nous nous sommes axés sur la détection de défauts internes et le diagnostic (localisation) rapide, d'une part par la surveillance directe et le seuillage des tensions internes (tensions flottantes) et d'autre part, par la détection d’harmoniques (amplitude et phase) en temps réel. Ces deux techniques ont été intégrées numériquement et évaluées sur le prototype, en particulier la seconde qui ne requiert qu'un seul capteur. Enfin, nous proposons une nouvelle variante PFC expérimentée en fin de mémoire, utilisant deux fois moins de transistors et de drivers pour les mêmes performances fréquentielles au prix d'un rendement et d'une répartition des pertes légèrement moins favorable que la structure brevetée
This work is an exploration and an evaluation of new variants of multi-level AC/DC topologies (PFC) considering their global reliability and availability: electrical safety with an internal failure and post-failure operation. They are based on a non-differential AC and centre tap connection that led to symmetrical arrangement cells in series. These topologies permit an intrinsic active redundancy between cells in a same group and a segregation capability between the two symmetrical groups of cells. More again, they are modular and they can be paralleled and derived to any number of levels. Only single low-voltage (600V) transistor pear cell is used avoiding the short-circuit risk due to an unwanted control signal. Comparisons, taking into account losses, distribution losses, rating and stresses (overvoltage and over-temperature) during the post-operation are presented. Results highlight the proposed 5-level Double-Boost Flying Capacitor topology. This one was patented at the beginning of thesis, as a solution with the best compromise. On the theoretical side, we show that the reliability calculation based only on a "first fault occurrence" criterion is inadequate to really describe this type of topology. The inclusion of fault tolerance capability is needed to evaluate the overall reliability law (i.e. including a second failure). The adaptation of theoretical models with constant failure rate including overvoltage and over-temperature dependencies exhibit an increasing of the reliability over a short time. This property is an advantage for embedded systems with monitoring condition. Local detection and rapid diagnosis of an internal failure were also examined in this work. Two methods are proposed firstly, by a direct flying caps monitoring and secondly, by a realtime and digital synchronous demodulation of the input sampled voltage at the switching frequency (magnitude and phase). Both techniques have been integrated on FPGA and DSP frame and evaluated on a AC230V-7kW DC800V – 31kHz lab. set-up. We put forward the interest of the second method which only uses one input voltage sensor. Finally, we propose in this dissertation a new generic X-level PFC Vienna using, in 5-level version, half transistors and drivers for identical input frequency and levels. At the cost of a slight increase of losses and density losses, this topology appears very attractive for the future. A preliminary lab. set-up and test were also realized and presented at the end of the thesis

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1999.
Includes bibliographical references (leaf 157).
For U.S. nuclear power stations to continue to generate electricity they must operate both safely and economically. Although the average safety and economic performance of U.S. power stations has improved over the past several years, some plants have not reached or have not sustained high performance levels. Stations achieving sustained high performance levels were identified by an analysis of safety and economic performance data. The core attributes considered necessary to achieve and maintain this level of performance were identified by interviews with executives from the stations and by analysis of effective programs and practices, Core attributes for long-term sustained high performance were determined to be: -- Strong teamwork among the plant staff. -- Extremely reliable equipment operation. -- Clear, effective communication throughout the station. -- Effective use of operating experience and benchmarking. -- Knowledgeable and involved station managers. -- Training focused on improving performance. -- Constant focus on safe plant operation. Recommended methods to identify shortfalls and improve core attribute performance at stations that have not achieved sustained high performance are self-assessment, development of station-wide core principles, and management and supervisory training.
by James E. Lynch.
M.Eng.

碩士
靜宜大學
企業管理研究所
97
Previous studies on learning have focused on organization level. This study emphasizes that the employee learning behavior is the most important factor to organization learning. Many studies have analyzed different level variables on the same level, which may lead to an inappropriate analytical fallacy. Furthermore, since the employees are nested in an organization, the employee behavior will be influenced by the organization field. This study focused on the psychological safety mechanism and structure method mechanism. The purpose of this study is building a multilevel approach to clear individual characteristics and organizational characteristics. This multilevel study of 197 employees, 26 managers from 26 high-technology companies located in three science parks in Taiwan demonstrates the results by using Hierarchical Linear Model (HLM). Firstly, individual-level learning behavior has a significantly positive association with employee task performance. Secondly, the main effect, aggregated structure method positively relates task performance, in the contrast; aggregated psychological safety has a negative influence on task performance. Further, structure method negatively moderates the relationship between learning behavior and task performance.

Traffic safety has been considered one of the most important issues in the transportation field. With consistent efforts of transportation engineers, Federal, State and local government officials, both fatalities and fatality rates from road traffic crashes in the United States have steadily declined from 2006 to 2011.Nevertheless, fatalities from traffic crashes slightly increased in 2012 (NHTSA, 2013). We lost 33,561 lives from road traffic crashes in the year 2012, and the road traffic crashes are still one of the leading causes of deaths, according to the Centers for Disease Control and Prevention (CDC). In recent years, efforts to incorporate traffic safety into transportation planning has been made, which is termed as transportation safety planning (TSP). The Safe, Affordable, Flexible Efficient, Transportation Equity Act – A Legacy for Users (SAFETEA-LU), which is compliant with the United States Code, compels the United States Department of Transportation to consider traffic safety in the long-term transportation planning process. Although considerable macro-level studies have been conducted to facilitate the implementation of TSP, still there are critical limitations in macroscopic safety studies are required to be investigated and remedied. First, TAZ (Traffic Analysis Zone), which is most widely used in travel demand forecasting, has crucial shortcomings for macro-level safety modeling. Moreover, macro-level safety models have accuracy problem. The low prediction power of the model may be caused by crashes that occur near the boundaries of zones, high-level aggregation, and neglecting spatial autocorrelation. In this dissertation, several methodologies are proposed to alleviate these limitations in the macro-level safety research. TSAZ (Traffic Safety Analysis Zone) is developed as a new zonal system for the macroscopic safety analysis and nested structured modeling method is suggested to improve the model performance. Also, a multivariate statistical modeling method for multiple crash types is proposed in this dissertation. Besides, a novel screening methodology for integrating two levels is suggested. The integrated screening method is suggested to overcome shortcomings of zonal-level screening, since the zonal-level screening cannot take specific sites with high risks into consideration. It is expected that the integrated screening approach can provide a comprehensive perspective by balancing two aspects: macroscopic and microscopic approaches.
Ph.D.
Doctorate
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Civil Engineering

Os Corpos de Bombeiros (CB) contam com uma rede de quartéis implantada em todo o território nacional, atualmente organizada por um modelo baseado nos limites territoriais das NUTS (Nomenclatura das Unidades Territoriais para Fins Estatísticos). Será, portanto, possível rentabilizar a rede de CB no patamar sub-regional, através da implementação de critérios de desempenho dos CB, entre eles, a população abrangida dentro dos tempos de resposta convencionados. O objetivo deste trabalho é propor uma reorganização operacional da rede de quartéis já implantada nas Sub-Regiões da Lezíria do Tejo e Médio Tejo, tendo como base um modelo da Rede Principal dos Serviços Operacionais dos Corpos de Bombeiros em Portugal Continental. Para tal, definiram-se critérios com vista à constituição de Agrupamentos de CB, que partilhando entre si áreas de atuação, permite priorizar o despacho de meios baseado no tempo de resposta dentro dos limites dos Agrupamentos. A aplicação dos critérios contemplando a rede viária existente e a distribuição da população residente, permitiu, recorrendo ao software QGIS®, aferir as zonas com necessidade de reforço da rede de quartéis. Aplicado o modelo à área de estudo, verificou-se um aumento de 18,4% (1.401 km2) de área e de 6,1% da população (30.524 habitantes) abrangidas dentro dos tempos de referência (10 e 20 minutos). Para garantir a atividade operacional nos 24 municípios abrangidos, a rede de CB contaria 24 quartéis sede e 22 postos avançados (reforço da atual rede com 8), guarnecidos no mínimo por um efetivo total de 1.897 bombeiros profissionais. O facto da rede de quartéis já se encontrar implantada no território alvo de estudo e apenas necessitar de reforços pontuais, deveria ser atualmente um fator desencadeador de interesse na sua rentabilização por parte das várias entidades envolvidas.
Fire Departments (CB) have a network of barracks deployed throughout the national territory, currently organized by a model based on the territorial limits of the NUTS (Nomenclature of Territorial Units for Statistical Purposes). Therefore, it will be possible to improve the fire department network at the sub-regional level, through the implementation of fire departments performance criteria, including the population coverage within the settled response times. The objective of this work is to propose an operational reorganization of the barracks network already implemented in the Sub-Regions of Lezíria do Tejo and Médio Tejo, based on a model of the Main Network of Operational Services for Fire Brigades in Mainland Portugal. To this end, criteria were defined with a view to the constitution of CB Groups, which sharing areas of activity among themselves, allows prioritizing the dispatch of means based on the response time within the limits of the Groups. The application of the criteria covering the existing road network and the distribution of the resident population, allowed, using the QGIS® software, to assess the areas in need of reinforcement of the barracks network. Applying the model to the Lezíria do Tejo and Médio Tejo sub-regions, there was an increase of 18,4% (1.401 km2) in area and 6,1% of the population (30.524 inhabitants) covered within the reference times (10 and 20 minutes). In order to guarantee operational activity in the 24 municipalities covered, the fire departments network would consist of a total of 24 headquarters and 22 outposts with a minimum of 1.897 professional firefighters. The fact that the barracks network is already implanted in the study target territory and only needs occasional reinforcements, should be a triggering factor of interest in its profitability by the various entities involved.