No description available.

Safety is an important aspect when designing bridges and roads. One aspect among others to consider is the road restraint systems. The focus of this study was centered to safety barriers which are the vehicle parapets/guardrails. The parapet must meet certain requirements specified in European Standard in order to obtain a CE-marking, indicating the acceptance of use. Full-scale test must be performed for a proposed parapet to evaluate the performance. Often several full-scale tests are performed in order to achieve CE-marking, making it an expensive process. The primary objective of this master thesis was to investigate if Abaqus/Explicit could be used as the finite element software for simulation of crashes. Secondary objective was to investigate how well a performed full-scale crash could be simulated in Abaqus/Explicit. A full-scale test was conducted and the parapet installation and vehicle used was modeled. Same conditions as in the full-scale were used in the simulation. The results indicated that it is possible to simulate the full-scale crash using Abaqus/Explicit. However, the behavior of the full-scale test was not completely captured. The maximum dynamic and permanent horizontal deflection of the tabular thrie beam in the full-scale test was 582 mm and 515 mm, corresponding value from the simulation was 703 mm and 643 mm. The conclusion from the results is that Abaqus/Explicit is a suitable finite element software for simulating crashes. The differences between the full-scale test and the simulations in this master thesis were due to the simplifications and assumptions used when modeling the parapet, bridge deck and the vehicle. The overall global behavior of the full-scale test was not captured, however the simulation results were not far from the full-scale test even though rough simplifications and assumptions were used in the modeling. We believe that with more care to details in modeling, it should be possible to have better convergence between simulation and the full-scale test.

No description available.

Motor vehicle crashes (MVCs) are a global public health concern. In 2020 alone, there were an estimated 6.76 million police reported crashes in the United States [1]. In the wake of an MVC, those involved may have been inflicted with serious or fatal injuries. Despite large research and development efforts to design vehicles and safety features to help reduce the frequency and severity of MVCs, crashes are, and will continue to be, a reality. In response to MVCs, first responders are tasked to provide crash victims with rapid immediate care and transport them to an appropriate facility. In spite of continued progress in emergency medicine, there are still many operational hurdles that emergency medical technicians need to overcome to perform their duties proficiently. Development and deployment of advanced automatic crash notification (AACN) systems have the potential to reduce the time between a crash and 911 system activation, especially for unseen roadway departures or crashes that render occupants incapacitated. Ultimately, AACN systems may aid first responders and improve MVC patient outcomes, however, these systems only target the earliest elements of an emergency response event. Therefore, the work contained in this dissertation aimed to identify additional areas for improvement within an emergency response event, specifically MVCs, and propose and/or develop solutions to address them. The first area pertained to emergency medical services (EMS) transportation, which can include responding to and transporting patients from an MVC. Through the analysis of the national EMS Information System database, an existing light vehicle naturalistic driving study, and a pilot ambulance-based naturalistic driving study, this dissertation provides a comprehensive investigation into EMS roadway interactions. The findings of these investigations confirmed that traffic interactions are a common issue and leading cause of EMS delay during response and transport phases. Even when ambulance operators drive with observed "due regard" and utilize emergency lights and sirens appropriate, many drivers were observed to yield the right of way inappropriately or in a delayed manner that resulted in safety critical events on open roadways and in intersections. The second area of improvement pertained to providing EMS with detailed patient information following an MVC. This took shape through the development of a post-crash injury triage system that provides first responders with occupant condition prior to on-scene arrival. The proposed system collects and shares crash occupant respiration rate, heart rate, and mental status through vehicle cabin integrated sensors and a post-crash response operator. This information, and additional vehicle specific crash details, are then populated into post-crash web application that responding agencies can view and interact with to strategically allocate response resources and predevelop transportation plans. Collectively, the work included in this dissertation identified challenges that EMS face when responding to MVCs, and produced findings that can be used to develop technology, update policies, and innovate in the transportation sector to improve emergency response and post-crash care. The identified safety and efficiency benefits not only apply to emergency respondents but encompass benefits to crash victims and all other road users. Although targeted at MVCs, the findings of this dissertation may also be applicable to many different types of emergencies and can benefit other public safety domains such as law enforcement, fire services, towing, and infrastructure maintenance. / Doctor of Philosophy / Motor vehicle crashes (MVCs) are a global public health concern. In 2020 alone, there were an estimated 6.76 million police reported crashes in the United States [1]. In the wake of an MVC, those involved may have been seriously or fatally injuries. Despite large research and development efforts to design vehicles and safety features to help reduce the frequency and severity of MVCs, crashes are, and will continue to be, a reality. In response to MVCs, first responders are tasked to provide crash victims with rapid immediate care and transport them to an appropriate facility. In spite of continued progress in emergency medicine, there are still many operational hurdles that emergency medical technicians need to overcome to perform their duties proficiently. Development and deployment of advanced automatic crash notification (AACN) systems have the potential to reduce the time between a crash when a 911 response is started, especially for unseen roadway departures or crashes that render occupants incapacitated. Ultimately, AACN systems may aid first responders and improve MVC patient outcomes, however, these systems only target the earliest elements of an emergency response event. Therefore, the work contained in this dissertation aimed to identify additional areas for improvement within an emergency response event, specifically MVCs, and propose and/or develop solutions to address them. The first area pertained to emergency medical services (EMS) transportation, which can include responding to and transporting patients from an MVC. Through the analysis of a national database, an existing light vehicle driving study, and a pilot ambulance-based driving study, this dissertation provides a comprehensive investigation into EMS roadway interactions. The findings can be used to better understand EMS roadway interactions and applied to develop innovative ways to improve safety and efficiency for all road users. The second area of improvement pertained to providing EMS with detailed patient information following an MVC. This took shape through the development of a post-crash injury triage system that provides first responders with occupant condition prior to on-scene arrival. The proposed system collects and shares crash occupant respiration rate, heart rate, and mental status, allowing responding agencies to strategically allocate response resources and predevelop transportation plans. Collectively, the work included in this dissertation identified challenges that EMS face when responding to MVCs, and produced findings that can be used to develop technology, update policies, and innovate in the transportation sector to improve emergency response and post-crash care. The identified safety and efficiency benefits not only apply to emergency respondents but encompass benefits to crash victims and all other road users. Although targeted at MVCs, the findings of this dissertation may also be applicable to many different types of emergencies and can benefit other public safety domains such as law enforcement, fire services, towing, and infrastructure maintenance. Therefore, the work contained in this dissertation aimed to identify additional areas for improvement within an emergency response event, specifically MVCs, and propose and/or develop solutions to address them. The first area pertained to emergency medical services (EMS) transportation, which can include responding to and transporting patients from an MVC. Through the analysis of a national database, an existing light vehicle naturalistic driving study, and a pilot ambulance-based naturalistic driving study, this dissertation provides a comprehensive investigation into EMS roadway interactions. The findings can be used to better understand EMS roadway interactions and applied to develop innovative ways to improve safety and efficiency for all road users. The second area of improvement pertained to providing EMS with detailed patient information following an MVC. This took shape through the development of a post-crash injury triage system that provides first responders with occupant condition prior to on-scene arrival. The proposed system collects and shares crash occupant respiration rate, heart rate, and mental status, allowing responding agencies to strategically allocate response resources and predevelop transportation plans. Collectively, the work included in this dissertation identified challenges that EMS face when responding to MVCs, and produced findings that can be used to develop technology, update policies, and innovate in the transportation sector to improve emergency response and post-crash care. The identified safety and efficiency benefits not only apply to emergency respondents but encompass benefits to crash victims and all other road users. Although targeted at MVCs, the findings of this dissertation may also be applicable to many different types of emergencies and can benefit other public safety domains such as law enforcement, fire services, towing, and infrastructure maintenance.

Automobile crashes are the largest cause of death for pregnant females and the leading cause of traumatic fetal injury mortality in the United States. The first way to protect the fetus is to protect the mother considering that maternal death has a near 100% fetal loss rate. If the mother survives, protection of the fetus may best be accomplished by preventing placental abruption. Placental abruption, which is the premature separation of the placenta from the uterus, has been shown to account for 50% to 70% of fetal losses in motor vehicle crashes. Since real world crash data for pregnant occupants is limited to a retrospective analysis and pregnant cadaver studies are not feasible, crash test dummies and computational modeling have been utilized to evaluate the risk of adverse fetal outcome. Although pregnant occupant research has progressed with these tools, they are based on limited tissue data. In order to have more accurate research tools, better pregnant tissue material data are needed. Therefore, the purpose of this dissertation is to provide material properties for the placenta and pregnant uterine tissue in dynamic tension. / Ph. D.

Historically, rear seat occupants have been at a lower risk of serious injury and fatality in motor vehicle crashes than their front seat counterparts. However, many passive safety advancements that have occurred over the past few decades such as advanced airbag and seatbelt technology primarily benefit occupants of the front seat. Indeed, safety for front seat occupants has improved drastically in the 21st century, but has it improved so much that the front seat is now safer than the rear? Today, rear-seated occupants account for 10% of all passenger vehicle fatalities. In this era focused on achieving zero traffic deaths, the safety of rear-seated occupants must be further addressed. This dissertation analyzed U.S. national crash data to quantify the risk of injury and fatality to rear-seated passenger vehicle occupants while accounting for the influence of associated crash, vehicle, and occupant characteristics such as crash severity, vehicle model year, and occupant age/sex. In rear impacts, the risk of moderate-to-fatal injury was greater for rear-seated occupants than their front-seated counterparts. In high-severity rear impact crashes, catastrophic occupant compartment collapse can occur and carries with it a great fatality risk. In frontal impacts, there is evidence that the rear versus front seat relative risk of fatality has been increasing in vehicle model years 2007 and newer. Rear-seated occupants often sustained serious thoracic, abdomen, and/or head injuries that are generally related to seatbelt use. Seatbelt pretensioners and load limiters – commonplace technology in the front seating positions – aim to mitigate these types of injuries but are rarely provided as standard safety equipment in the rear seats of vehicles today. Finally, in side impacts, injury and fatality risks to rear- and front-seated occupants are more similar than in the other crash modes studied, though disparities in protection remain, especially in near-side vehicle-to-vehicle crashes. Finally, this work projects great injury reduction benefits if a rear seat belt reminder system were to be widely implemented in the U.S. vehicle fleet. This dissertation presents a comprehensive investigation of the factors that contribute to rear-seated occupant injury and/or fatality through retrospective studies on rear, front, and side impacts. The overall goal of this dissertation is to better quantify the current risk of injury to rear-seated occupants under a variety of crash conditions, compare this to the current risk to front-seated occupants, and, when possible, identify how exactly injuries are occurring and ways in which they may be prevented in the future. The findings can benefit automakers who seek to improve the effectiveness of rear seat safety systems as well as regulatory agencies seeking to improve was vehicle tests targeting rear seat passenger vehicle safety. / Doctor of Philosophy / Historically, if a passenger vehicle such as a sedan or SUV is in a crash, occupants who are rear-seated were less likely to be hurt than someone who was front-seated. In other words, rear-seated occupants have been at a lower risk of injury than front-seated occupants. Indeed, safety for front seat occupants has improved drastically in the 21st century due to advancements in airbag and seatbelt technologies, among others, but has it improved so much that the front seat is now safer than the rear? Today, of all vehicle occupants who are killed in crashes on U.S. roadways, 10% are rear-seated. During this time when conversations surrounding vehicle safety are focused on achieving zero traffic deaths, the safety of rear-seated occupants must be further studied. This dissertation looked at national databases of all police-reported crashes that occur each year in the United States. The risk of injury to rear-seated passenger vehicle occupants was quantified and compared to that of front-seated occupants. Factors that may increase or decrease this risk of injury and fatality such as crash type, vehicle type, and occupant demographics were further explored and reported. In vehicles that were rear-ended, the risk of injury was greater for rear-seated occupants than their front-seated counterparts. When a vehicle crashes into something front-first (the most common type of impact in a vehicle crash), evidence is presented that the risk of fatality is greater in the rear seats than the front seats in model year 2007 and newer vehicles which generally are equipped with the most recent airbag and seatbelt technology. When a vehicle is hit on either of its sides, the risk of injury is closer between rear- and front-seated occupants than it was in the rear-end or frontal crashes previously studied. That said, differences in occupant protection were still observed between the rear and front seats, especially when the occupants studied were seated on the closest side of impact, or the near-side, and the vehicle was struck by another vehicle rather than sliding into an object such as a pole. Finally, this work projects great injury reduction benefits if a rear seat belt reminder system were to be widely implemented in the U.S. vehicle fleet. This dissertation presents a comprehensive investigation of the factors that contribute to rear-seated occupant injury and/or fatality through retrospective studies on rear, front, and side impacts. The overall goal of this dissertation is to better quantify the current risk of injury to rear-seated occupants under a variety of crash conditions, compare this to the current risk to front-seated occupants, and, when possible, identify how exactly injuries are occurring and ways in which they may be prevented in the future. The findings can benefit automakers who seek to improve the effectiveness of rear seat safety systems as well as regulatory agencies seeking to improve was vehicle tests targeting rear seat passenger vehicle safety.

O Atendimento Pré Hospitalar (APH) é um importante recurso no atendimento à vítimas de trauma. No entanto, há muitas dificuldades para demonstrar o efeito benéfico das intervenções do APH na sobrevivência das vítimas, sobretudo as de suporte avançado à vida (SAV). A proposta deste estudo é caracterizar as vítimas de acidentes trânsito, com Revised Trauma Score (RTS) <11, atendidas pelo SAV municipal e encaminhadas a hospitais terciários em São Paulo, além de identificar as variáveis da fase pré-hospitalar associadas à sobrevivência e avaliar o valor predeterminante dessas variáveis sobre o resultado obtido pelas vítimas. As variáveis avaliadas foram: sexo, idade, mecanismos do acidente, procedimentos de suporte básico e SAV realizados, repercussão fisiológica do trauma na cena do acidente, (considerando o RTS , seus parâmetros e flutuações), o tempo consumido no APH, gravidade do trauma segundo o Injury Severity Score (ISS),a Maximum Abbreviated Injury Scale (MAIS) e número de lesões para cada segmento corporal. Os resultados obtidos por 175 vítimas entre 12 e 65 anos, foram submetidos a "Análise de Sobrevivência de Kaplan Meier" e ao “Modelo de Riscos Proporcionais de Cox". A variável dependente foi o tempo de sobrevivência após o acidente, considerando os intervalos até 6h,12h, 24h, 48h, até 7 dias e até o término da internação. Os homens (86,9%) e a faixa etária de 20 a 29 anos (36,0%) foram as mais freqüentes. Os atropelamentos (45,1%) e o envolvimento de motocicletas e seus ocupantes (30,9%) foram os destaques dentre os mecanismos de trauma. A média do RTS na cena e do ISS, foram respectivamente 8,8 e 19,4.Os segmentos corpóreos mais atingidos foram: cabeça (58,8%), membros inferiores (45,1%) e superfície externa (40%). A média de tempo consumido na fase de APH foi 41min (tempo de cena 20,2min). Ocorreram 36% de óbitos, (metade em até 6 horas). A análise estatística revelou 24 fatores associados à sobrevivência, dentre eles, os procedimentos respiratórios avançados e os circulatórios básicos, as variáveis relativas ao RTS e a gravidade (ISS, MAIS e o número de lesões). No modelo final de Cox, ter sido submetido a procedimentos respiratórios avançados, compressões torácicas, apresentar lesão abdominal e ISS>25, foi associado a maior risco para o óbito até 48h após o trauma. Até 7 dias, a compressão torácica não se manteve no modelo final e a PAS de zero a 75mmHg apresentou associação com a morte após o acidente. Até a alta hospitalar, a ausência de PAS na avaliação inicial permaneceu no modelo. A reposição de volume foi o único fator com valor protetor para o risco de óbito presente em todos os momentos / The prehospital care (PH) is an important resource to trauma victims’ care. Nevertheless, there is great difficulty in demonstrating the PH intervention’s positive effect in victim’s survival, especially when concerning the advanced life support (ALS). The aim of this study is to characterize motor vehicle crash victims with Revised Trauma Score (RTS) <11 cared by municipal ALS and moved to tertiary hospitals in São Paulo in addition to identifying the prehospital variables associated to survival, and to evaluate their values as victim survival outcome determinant. The variables evaluated were: sex, age, trauma mechanism, basic life support and ALS procedures, physiological measures in the accident scene (considering the RTS, its parameters and fluctuations), the time consumed in PH phase, trauma severity by Injury Severity Score (ISS), the Maximum Abbreviated Injury Scale (MAIS) and number of lesions in each body region. The main results obtained by 175 victims between 12 e 65 years of age were submitted to the Kaplan Meier Survival Analysis and to Cox Proportional hazards Regression Analysis. The dependent variable was the survival time after the motor vehicle accident considering the intervals up to 6,12,24 and 48hs , up to 7 days and until the time of hospital discharge. Men (86,9%) and the 20 to 29 aged group (36%) were the most frequent. The pedestrians struck by car (45,1%) and the motorcycles (and their riders) (30,9%)were the highlight in trauma mechanisms. The RTS and the ISS average were 8,8 and 19,4 respectively. The more damaged body regions were head (58,8%), lower limbs (45,1%) and external surface (40%).The prehospital time average was 41 min (scene time 20,2min).Death rate was 36% (half of which up to 6hs).The statistical analysis revealed 24 survival associated factors. The ALS and the circulatory basic procedures, the RTS variables and the trauma severity (ISS,MAIS and number of lesions) were within them. In the final Cox Model were associated to higher risk of death up to 48hs after trauma: the submission to ALS respiratory procedures, chest compressions, the presence of abdominal injuries and ISS>25 .Until the 7th day the chest compression was not sustained in a final model and the systolic blood pressure (SBP) from zero to 75mmHg revealed statistical association with death after trauma. Until hospital discharge the SBP absence in scene evaluation remained in the model. The prehospital intravenous fluid refilling was the only factor of protector value to death risk in all moments

O Atendimento Pré Hospitalar (APH) é um importante recurso no atendimento à vítimas de trauma. No entanto, há muitas dificuldades para demonstrar o efeito benéfico das intervenções do APH na sobrevivência das vítimas, sobretudo as de suporte avançado à vida (SAV). A proposta deste estudo é caracterizar as vítimas de acidentes trânsito, com Revised Trauma Score (RTS) <11, atendidas pelo SAV municipal e encaminhadas a hospitais terciários em São Paulo, além de identificar as variáveis da fase pré-hospitalar associadas à sobrevivência e avaliar o valor predeterminante dessas variáveis sobre o resultado obtido pelas vítimas. As variáveis avaliadas foram: sexo, idade, mecanismos do acidente, procedimentos de suporte básico e SAV realizados, repercussão fisiológica do trauma na cena do acidente, (considerando o RTS , seus parâmetros e flutuações), o tempo consumido no APH, gravidade do trauma segundo o Injury Severity Score (ISS),a Maximum Abbreviated Injury Scale (MAIS) e número de lesões para cada segmento corporal. Os resultados obtidos por 175 vítimas entre 12 e 65 anos, foram submetidos a ”Análise de Sobrevivência de Kaplan Meier” e ao “Modelo de Riscos Proporcionais de Cox”. A variável dependente foi o tempo de sobrevivência após o acidente, considerando os intervalos até 6h,12h, 24h, 48h, até 7 dias e até o término da internação. Os homens (86,9%) e a faixa etária de 20 a 29 anos (36,0%) foram as mais freqüentes. Os atropelamentos (45,1%) e o envolvimento de motocicletas e seus ocupantes (30,9%) foram os destaques dentre os mecanismos de trauma. A média do RTS na cena e do ISS, foram respectivamente 8,8 e 19,4.Os segmentos corpóreos mais atingidos foram: cabeça (58,8%), membros inferiores (45,1%) e superfície externa (40%). A média de tempo consumido na fase de APH foi 41min (tempo de cena 20,2min). Ocorreram 36% de óbitos, (metade em até 6 horas). A análise estatística revelou 24 fatores associados à sobrevivência, dentre eles, os procedimentos respiratórios avançados e os circulatórios básicos, as variáveis relativas ao RTS e a gravidade (ISS, MAIS e o número de lesões). No modelo final de Cox, ter sido submetido a procedimentos respiratórios avançados, compressões torácicas, apresentar lesão abdominal e ISS>25, foi associado a maior risco para o óbito até 48h após o trauma. Até 7 dias, a compressão torácica não se manteve no modelo final e a PAS de zero a 75mmHg apresentou associação com a morte após o acidente. Até a alta hospitalar, a ausência de PAS na avaliação inicial permaneceu no modelo. A reposição de volume foi o único fator com valor protetor para o risco de óbito presente em todos os momentos / The prehospital care (PH) is an important resource to trauma victims’ care. Nevertheless, there is great difficulty in demonstrating the PH intervention’s positive effect in victim’s survival, especially when concerning the advanced life support (ALS). The aim of this study is to characterize motor vehicle crash victims with Revised Trauma Score (RTS) <11 cared by municipal ALS and moved to tertiary hospitals in São Paulo in addition to identifying the prehospital variables associated to survival, and to evaluate their values as victim survival outcome determinant. The variables evaluated were: sex, age, trauma mechanism, basic life support and ALS procedures, physiological measures in the accident scene (considering the RTS, its parameters and fluctuations), the time consumed in PH phase, trauma severity by Injury Severity Score (ISS), the Maximum Abbreviated Injury Scale (MAIS) and number of lesions in each body region. The main results obtained by 175 victims between 12 e 65 years of age were submitted to the Kaplan Meier Survival Analysis and to Cox Proportional hazards Regression Analysis. The dependent variable was the survival time after the motor vehicle accident considering the intervals up to 6,12,24 and 48hs , up to 7 days and until the time of hospital discharge. Men (86,9%) and the 20 to 29 aged group (36%) were the most frequent. The pedestrians struck by car (45,1%) and the motorcycles (and their riders) (30,9%)were the highlight in trauma mechanisms. The RTS and the ISS average were 8,8 and 19,4 respectively. The more damaged body regions were head (58,8%), lower limbs (45,1%) and external surface (40%).The prehospital time average was 41 min (scene time 20,2min).Death rate was 36% (half of which up to 6hs).The statistical analysis revealed 24 survival associated factors. The ALS and the circulatory basic procedures, the RTS variables and the trauma severity (ISS,MAIS and number of lesions) were within them. In the final Cox Model were associated to higher risk of death up to 48hs after trauma: the submission to ALS respiratory procedures, chest compressions, the presence of abdominal injuries and ISS>25 .Until the 7th day the chest compression was not sustained in a final model and the systolic blood pressure (SBP) from zero to 75mmHg revealed statistical association with death after trauma. Until hospital discharge the SBP absence in scene evaluation remained in the model. The prehospital intravenous fluid refilling was the only factor of protector value to death risk in all moments

No description available.

Seat belts save lives; however, unintentional injuries are still the leading cause of death for those between 1 and 44 years in the United States. Seat belts also cause injuries during motor vehicle crashes (MVCs) and obesity changes how seat belts fit. The purpose of this retrospective causal inference quantitative study was to reduce the knowledge gap in scholarly research on seat belt fit in relation to blunt cerebrovascular injuries (BCVI) during MVCs and seat belt compliance. The theoretical framework used was based on H.W. Heinrich's domino theory. The research questions focused on the following dependent variables: BCVI, compliance, and seat belt fit; and independent variables: the size of the individual and seat belt fit. Secondary and primary data were used and analyzed using Spearman's Rank-Order Correlation. The results yielded no relationship between seat belt fit and BCVI in the secondary data (n = 97). In the primary data (n = 138), there was significance found between seatbelt fit and a) seat belt use, and b) BMI. The study contributed to positive social change by enhancing the awareness of the knowledge deficit regarding seat belt fit, and BCVIs sustained during MVCs, and that comfort was influenced by seat belt fit and had a role in compliance. Seat belts were not used by 5.3% and 9.5% or used incorrectly by 3.2% and 2.9% of the people in the primary data and secondary data sets. This knowledge may contribute to a) future seat belt testing to ensure it is done in such a manner that seat belts fit everyone; b) new seat belt laws to ensure that they are consistent across all states, and c) medical care focusing on seat belt fit as a mechanism of injury (blunt) to ensure screenings are done with the appropriate diagnostic tools.