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1.
Forensic Sci Rev ; 32(1): 55-81, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32007928

RESUMEN

This review focuses on the role of motor vehicles in the prevention of alcohol-related fatalities in the United States. Since alcohol significantly affects brain function, it is natural to make drivers the prime targets for impaired-driving-prevention programs. However, the prevalence, design, ease of operation, and safety features of motor vehicles, as well as state regulations of their operation, have an important influence on crash occurrences, particularly those involving alcohol. This review begins with a discussion of why the automobile became the central technological device in the alcohol-related fatality problem and then moves on to an overview of motor vehicle safety programs that have impacted impaired driving. The article then presents an extended discussion of the effectiveness of vehicle-based, alcohol-detecting ignition interlock devices (interlocks), which provided the principal specific vehicle-based effort in the 20th century to separate alcohol consumption from driving. The review ends with a commentary on the issues that will arise in managing operator impairment in autonomous (self-driving) vehicles-the probable principal 21st-century effort to reduce impaired driving and eliminate alcohol-related crashes by minimizing the role of the driver.


Asunto(s)
Accidentes de Tránsito/prevención & control , Conducir bajo la Influencia , Vehículos a Motor , Equipos de Seguridad , Accidentes de Tránsito/estadística & datos numéricos , Humanos , Estados Unidos
2.
Medicine (Baltimore) ; 99(5): e18654, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32000370

RESUMEN

INTRODUCTION: Acute hydrocephalus is a common complication of spontaneous or traumatic intracranial bleeding with extensive subarachnoid hemorrhage (SAH) or ventricular extension. However, it has never been reported to be secondary to pneumocephalus. PATIENT CONCERNS: A 32-year-old man was admitted following a motorcycle accident. Head computed tomography (CT) performed right after the accident revealed a skull base fracture and mild perimesencephalic SAH. Three days later, repeated CT revealed delayed perimesencephalic pneumocephalus and an evident enlargement of the ventricular system. DIAGNOSIS: The patient was diagnosed with acute obstructive hydrocephalus, which was secondary to pneumocephalus and traumatic SAH. INTERVENTIONS: The patient was treated with temporary external ventricular drainage (EVD). OUTCOMES: The patient experienced an unremarkable recovery process. At follow-up 3 months later, he showed no recurrence of the hydrocephalus and the score of Glasgow Outcome Scale was 5. CONCLUSION: Transient mechanical obstruction of CSF circulation and disturbance of CSF physiology might conjointly lead to the acute obstructive hydrocephalus.


Asunto(s)
Hidrocefalia/etiología , Neumocéfalo/complicaciones , Fractura Craneal Basilar/complicaciones , Hemorragia Subaracnoidea/complicaciones , Accidentes de Tránsito , Adulto , Humanos , Masculino , Neumocéfalo/diagnóstico por imagen , Fractura Craneal Basilar/diagnóstico por imagen
3.
Recurso de Internet en Portugués | LIS - Localizador de Información en Salud | ID: lis-LISBR1.1-46969

RESUMEN

Entrevista com a pesquisadora Ednilsa da Silva Ramos concedida ao informe ENSP sobre a assinatura da medida provisória que extingue o Seguro Obrigatório de Danos Pessoais (DPVAT) causados por veículos automotores tem levantado questões sobre o real impacto dessa decisão para as vítimas de acidente de trânsito. Com o estabelecimento da medida, que passará a vigorar em 2020, as indenizações às vítimas de trânsito serão encerradas a partir do ano que vem. Além disso, o SUS deixará de receber o valor de 45%, que atualmente arrecada com o seguro.


Asunto(s)
Accidentes de Tránsito , Pacientes no Asegurados , Sistema Único de Salud , Difusión por la Web , Entrevista
4.
Br J Radiol ; 93(1106): 20190017, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31899661

RESUMEN

Paediatric aortic trauma is a rare injury which can be fatal if not identified and managed appropriately. Surgical repair remains the gold-standard in moderate to severe aortic injuries. In the last decade however, endovascular treatment has gained popularity in children who have suitable vascular anatomy for intervention and are either not fit for surgery or in whom, endovascular intervention is the only alternative that will make a difference in the clinical outcome. Children pose a unique set of challenges to endovascular therapy. In this article, we aim to illustrate the different endovascular options that are available for the treatment of acute traumatic aortic injury and visceral thromboembolisation through pictorial representation. We will also demonstrate the feasibility and the limitation of this technique.


Asunto(s)
Aorta Abdominal/lesiones , Aorta Torácica/lesiones , Procedimientos Endovasculares , Heridas no Penetrantes/cirugía , Heridas Punzantes/cirugía , Accidentes de Tránsito , Adolescente , Aorta Abdominal/cirugía , Aorta Torácica/cirugía , Niño , Preescolar , Angiografía por Tomografía Computarizada , Estudios de Factibilidad , Humanos , Angiografía por Resonancia Magnética , Masculino , Heridas no Penetrantes/diagnóstico , Heridas Punzantes/diagnóstico
5.
Khirurgiia (Mosk) ; (1): 74-79, 2020.
Artículo en Ruso | MEDLINE | ID: mdl-31994503

RESUMEN

A 8-year-old child with multiple skeletal injuries after car accident is presented in the article. Extensive right-sided urohematoma with impaired kidney function was diagnosed after 15 days. External drainage of urohematoma, ureteroscopy and examination of the right kidney were consecutively performed within 1.5 months. A complete rupture of the right ureter at the level of pyeloureterostomy was diagnosed. Right kidney autotransplantation with ureteral resection and pyeloureteral anastomosis were performed in 2 months after injury. Duration of surgery was 7.5 hours, cold ischemia - 55 min. Postoperative examination confirmed satisfactory function of the right kidney. This observation is relatively rare and the first in Russia.


Asunto(s)
Traumatismos Abdominales/cirugía , Trasplante de Riñón , Reimplantación , Uréter/lesiones , Uréter/cirugía , Heridas no Penetrantes/cirugía , Traumatismos Abdominales/complicaciones , Accidentes de Tránsito , Niño , Humanos , Riñón/lesiones , Riñón/cirugía , Traumatismo Múltiple/complicaciones , Traumatismo Múltiple/cirugía , Trasplante Autólogo , Heridas no Penetrantes/complicaciones
6.
Medicine (Baltimore) ; 99(1): e18567, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31895799

RESUMEN

We investigated the epidemiological and clinical characteristics deaths from road traffic injury (RTI) in Beijing, and provided evidence useful for the prevention of fatal traffic trauma and for the treatment of traffic-related injuries.We retrospectively reviewed death cases provided by the Beijing Red Cross Emergency Center on road traffic injury deaths from 2008 to 2017. We analyzed population characteristics, time distribution, distribution of transportation modes, intervals to death, locations and injured body parts.From 2008 to 2017, there were 3327 deaths from RTI recorded by the Beijing Red Cross Emergency Center, with mainly males among these deaths. The average age at death was 46.19 ±â€Š17.43 years old (46.19, 0.43-100.24). In accidents with more detail recorded, pedestrians and people using nonmotorized transportation modes suffered the most fatalities (664/968, 68.60%). The most commonly injured body parts were the head (2569/3327, 77.22%), followed by the chest (180/3327, 5.41%), abdomen (130/3327, 3.91%), lower extremities (68/3327, 2.04%), pelvis (67/3327, 2.01%), spinal cord (31/3327, 0.93%), and upper extremities (26/3327, 0.78%). Burns accounted for 0.96% (32/3327), and unknown body parts were affected in 11.28% (365/3327). The average time interval from injury to death was 36.90 ±â€Š89.57 h (36.90, 0-720); 46.7% (1554/3327) died within 10 minutes after injury; 9.02% (300/3327) died between 10 min and 1 hour; 30.33% (1009/3327) died between 1 hour and 3 days; 13.95% (464/3327) died between 3 and 30 days.In Beijing, RTI is a significant cause of preventable death, particularly among pedestrians and users of non-motorized vehicles. Head trauma was the most lethal cause of RTI deaths. Our findings suggested that interventions to prevent collisions and reduce injuries, and improved trauma treatment process and trauma rescue system could address a certain proportion of avoidable RTI deaths.


Asunto(s)
Accidentes de Tránsito/mortalidad , Traumatismos Craneocerebrales/mortalidad , Peatones/estadística & datos numéricos , Heridas y Traumatismos/mortalidad , Adulto , Anciano , Beijing/epidemiología , Traumatismos Craneocerebrales/etiología , Servicio de Urgencia en Hospital/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Centros Traumatológicos/estadística & datos numéricos , Heridas y Traumatismos/etiología
7.
Am J Forensic Med Pathol ; 41(1): 52-55, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31895099

RESUMEN

Characteristic injury patterns have been described in pedestrians struck by motor vehicles. The common injury pattern seen in upright pedestrians consists of a triad of head, pelvis, and lower extremity trauma. There are several factors such as vehicular type, design, mass and speed, and impact surfaces that influence the type and distribution of these injuries. We report a case that illustrates the importance of examination of the knee at autopsy when the typical lower extremity diaphyseal fractures that are usually seen in a motor vehicle-pedestrian collision are absent.


Asunto(s)
Accidentes de Tránsito , Fracturas del Fémur/patología , Traumatismos de la Rodilla/patología , Peatones , Adulto , Medicina Legal/métodos , Humanos , Masculino , Traumatismo Múltiple/patología , Trastornos Relacionados con Sustancias , Heridas no Penetrantes/patología
8.
Forensic Sci Int ; 306: 110059, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31780351

RESUMEN

In traffic accidents, the differentiation of run-over and other injuries is crucial because questions about the origin of fatal injuries often arise. It is sometimes difficult for forensic pathologists to answer them due to the superimposition of injuries or competing, potentially fatal findings. Therefore, using morphometric three-dimensional (3D) reconstructions offers new perspectives based on an interdisciplinary evaluation of all findings and traces. The morphometric 3D reconstruction includes the allocation of patterned injuries or transferred material, the determination of the origin of injuries as well as the reconstruction of the incident. The generated 3D models of persons, clothes, vehicles, incident sites and relevant objects resulting from forensic imaging, photogrammetry, 3D structured-light and laser scanning are included, as are all detected traces and damages. Three case studies are presented to illustrate the possibilities and results of morphometric 3D reconstruction. Run-over accidents have received less attention than the topic of pedestrian, bicycle and motorbike accident analysis for which there is a large body of literature. Our goal is to add to the understanding of run-over accidents using morphometric reconstruction in order to improve their analysis in the future. The possibilities of morphometric reconstructions by means of 3D techniques in run-over accidents are wide-ranging and can provide new, unexpected and significant insights.


Asunto(s)
Accidentes de Tránsito , Simulación por Computador , Medicina Legal/métodos , Imagen Tridimensional , Peatones , Humanos , Rayos Láser , Imagen por Resonancia Magnética , Masculino , Fotogrametría , Programas Informáticos , Tomografía Computarizada por Rayos X , Heridas y Traumatismos/patología
9.
J Forensic Sci ; 65(1): 193-195, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31433492

RESUMEN

The interpretation of cranial base injuries has never been investigated from a purely anthropological perspective. Very little exists in forensic literature in order to interpret the significance of cranial base fractures. We analyzed 296 cases of deaths due to skull-brain injuries. The frequency of vault fractures was 75.7% and that of base fractures was 91.9%. We observed the distribution of cases of death according to manner of death and manner of injury and number of fossae involved. These observations were analytically compared to different variables (age, sex, manner of injury, and mode of injury). The study presented the proportion of base fractures associated with vault fractures, and the frequency of absence of base fracture in subjects with no vault fractures. Interesting associations of base fractures to age and manner of death are shown.


Asunto(s)
Lesiones Encefálicas/mortalidad , Base del Cráneo/lesiones , Fracturas Craneales/epidemiología , Accidentes por Caídas/mortalidad , Accidentes de Tránsito/mortalidad , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Lactante , Italia/epidemiología , Masculino , Persona de Mediana Edad , Abuso Físico/estadística & datos numéricos , Distribución por Sexo , Base del Cráneo/patología , Fracturas Craneales/patología , Heridas por Arma de Fuego/mortalidad , Adulto Joven
10.
J Surg Res ; 245: 373-376, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31425878

RESUMEN

BACKGROUND: Recently, there has been an increase in the usage of dirt bikes and all-terrain vehicles in urban environments. Previously, it has been shown that crashes involving these urban off-road vehicles (UORVs) resulted in different injury patterns from crashes that occurred in rural environments. The aim of this study was to compare injury patterns of patients involved in crashes while riding UORVs versus motorcycles (MCs). METHODS: A retrospective review (2005-2016) of patients who presented to our urban level I trauma center as a result of any MC or UORV crash was performed. Patients who presented after 48 h from the time of accident were excluded. A P < 0.05 was considered significant. RESULTS: We identified 1556 patients who were involved in an MC or UORV crash resulting in injury (MC: n = 1324 [85%]; UORVs: n = 232 [15%]). Patients in UORV crashes were younger (26.2 y versus 39.6 y), less likely to be helmeted (39.6% versus 90.2%), required fewer emergent trauma bay procedures (28.4% versus 36.7%), and needed fewer operative interventions (45.9% versus 54.2%) (all P < 0.05). Both groups had a similar Injury Severity Score (12.2 versus 12.6; P = 0.54) and Glasgow Coma Score (13.8 versus 13.5; P = 0.46). UORV patients had a lower mortality (0.9% versus 4.7%; P < 0.05) compared to MC crash patients despite similar injury patterns. CONCLUSIONS: Our data demonstrate that patients sustaining UORV injuries were younger and less likely to be helmeted but have a lower mortality rate after a crash, despite sustaining similar injuries as motorcyclists. This study provides an overview of how crashes involving UORV usage is a unique phenomenon and not entirely comparable to MC crashes.


Asunto(s)
Accidentes de Tránsito/estadística & datos numéricos , Motocicletas/estadística & datos numéricos , Vehículos a Motor Todoterreno/estadística & datos numéricos , Heridas y Traumatismos/epidemiología , Adulto , Femenino , Humanos , Masculino , New Jersey/epidemiología , Estudios Retrospectivos
11.
Accid Anal Prev ; 134: 105251, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31402051

RESUMEN

Powered two-wheelers (PTWs) are growing globally each year as they are considered an attractive alternative to cars (flexible, small, affordable, fast and easy to park), especially on congested traffic situations. However, PTWs represent an important challenge for road safety. In fact, in 2016, Spain ranked fifth in terms of PTW fatalities among EU 28. For this reason, this paper aims to investigate which are the patterns among crash characteristics contributing to PTW crashes in Spain. Data from 78,611 crashes involving PTWs occurred in Spain in the period 2011-2013 were analyzed. The analysis was performed by using classification trees and rules discovery which are suitable models aimed at extracting knowledge and identifying valid and understandable patterns from large amounts of data previously unknown and indistinguishable. The response variables assessed in this study were severity and crash type. As a result, several combinations of road, environmental and drivers' characteristics associated with severity and typology of PTW crashes in Spain were identified. Based on the analysis results, several countermeasures to solve or mitigate the safety issues identified in the study were proposed. From the methodological point of view, study results show that both the classification trees and the a priori algorithm were effective in providing non-trivial and unsuspected relations in the data. Classification trees structure allowed a simpler understanding of the phenomenon under study while association discovery provided new information which was previously hidden in the data. Given that the results of the two different techniques were never contradictory, we recommend using classification trees and association discovery as complementary approaches since their combination is effective in exploring data providing meaningful insights about PTW crash characteristics and their interdependencies.


Asunto(s)
Accidentes de Tránsito/mortalidad , Minería de Datos/métodos , Motocicletas/estadística & datos numéricos , Algoritmos , Humanos , Curva ROC , España/epidemiología
12.
Accid Anal Prev ; 134: 105247, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31405514

RESUMEN

Using data from the national register of police-reported crashes and from the bridge register of the Norwegian Public Roads Administration, we estimated rates of single-vehicle crashes on road sections adjacent to road bridges and on different sections of the bridges. Data included all single-vehicle personal injury crashes occurring on or close to road bridges in Norway between 2010 and 2016, a total of 219 crashes. All bridges on state and county roads were included. Crash rate was found to be highest in the approach zone of short bridges (last 50 m before bridge) and lowest in the middle of long bridges. On bridges shorter than about 100 m, crash rate was higher in the first than in the last bridge zone. Total crash rate on bridges was close to the figure for the total road network. However, for the approach to short bridges, crash rate was significantly higher than for the total road network, and for the middle part of long bridges it was significantly lower. A supplementary analysis of in-depth data from 31 fatal crashes including both single-vehicle and multiple-vehicle crashes supported the results from the main analysis. A higher proportion of fatal crashes occurred on approaching or entering a bridge than when leaving the bridge, as seen from the direction of travel of the at-fault vehicle. Concerning countermeasures against bridge accidents, particular attention should be payed to the approach zone and to the design of barriers.


Asunto(s)
Accidentes de Tránsito/mortalidad , Entorno Construido , Accidentes de Tránsito/estadística & datos numéricos , Humanos , Noruega , Factores de Riesgo
13.
Accid Anal Prev ; 134: 105244, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31405515

RESUMEN

This paper reviews the literature on the relationship between the built environment and roadway safety, with a focus on studies that analyse small geographical units, such as census tracts or travel analysis zones. We review different types of built environment measures to analyse if there are consistent relationships between such measures and crash frequency, finding that for many built environment variables there are mixed or contradictory correlations. We turn to the treatment of exposure, because built environment measures are often used, either explicitly or implicitly, as measures of exposure. We find that because exposure is often not adequately controlled for, correlations between built environment features and crash rates could be due to either higher levels of exposure or higher rates of crash risk per unit of exposure. Then, we identify various built environment variables as either more related to exposure, more related to risk, or ambiguous, and recommend further targeted research on those variables whose relationship is currently ambiguous.


Asunto(s)
Accidentes de Tránsito , Entorno Construido , Humanos , Densidad de Población , Medición de Riesgo , Seguridad , Análisis Espacial
14.
Accid Anal Prev ; 134: 105234, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31443915

RESUMEN

BACKGROUND: Insufficient sleep, <6.5 h per night, majorly affects shift workers, placing them at higher risk for motor vehicle crash related injury or fatality. While systematic reviews (SLRs) examine the effects of insufficient sleep and driving, to date, no SLR focuses on driver fitness or performance in shift workers. OBJECTIVES: Determine the class of evidence (Class I-highest to Class IV-lowest), and level of confidence (Level A-high, to Level U-insufficient) in the determinants of driver fitness and performance in shift workers. Next, consider evidence-based recommendations for clinical practice, research, and policy. METHODS: A protocol was registered on PROSPERO (#CRD42018052905) using an established SLR methodology: a comprehensive electronic database search, study selection, data extraction, critical appraisal, analysis, and interpretation using published guidelines. RESULTS: Searches identified 1226 unique records with 11(2 on-road, 9 simulator) meeting final inclusion criteria. Class III to IV evidence identified that exposure to overnight shift work possibly predicts (Level C confidence) drivers at risk for adverse on-road outcomes and likely predicts (Level B) drivers at risk for adverse driving simulator outcomes. Higher ratings of subjective sleepiness and extended time driving possibly predict (Level C) drivers at risk for adverse driving simulator outcomes. CONCLUSIONS: This study demonstrates a low to moderate level of confidence in the determinants of driving in shift workers. A critical need exists for gold-standard on-road assessments integrating complex driving environments representative of real-world demands, targeting tactical and strategic outcomes in a broad spectrum of shift workers.


Asunto(s)
Accidentes de Tránsito/estadística & datos numéricos , Privación de Sueño/complicaciones , Somnolencia , Tolerancia al Trabajo Programado , Adulto , Conducción de Automóvil , Femenino , Humanos , Masculino , Medición de Riesgo , Vigilia
15.
Accid Anal Prev ; 134: 105235, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31561839

RESUMEN

To improve the road safety, policy makers relay on data analysis to enact new traffic policies. Accordingly, statistical modeling has been linked in various studies of road crash counts with excess zeros. On top of this excess zero problem, missing data are also likely to occur in the road traffic accident data. Unless the missing data are resulted randomly, the popular naive estimation may not provide reliable results for policy making. In contrast, the implementation of the Horvitz method, which inversely weights the observed data by a weight that are obtained parametrically or nonparametrically, results in reliable estimators. We received satisfactory results on the performance of our approach handling the missing data problems in both a Monte Carlo simulation and a real traffic accident data exploration.


Asunto(s)
Accidentes de Tránsito/estadística & datos numéricos , Exactitud de los Datos , Humanos , Modelos Estadísticos , Método de Montecarlo , Distribución de Poisson
16.
Accid Anal Prev ; 134: 105324, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31648116

RESUMEN

OBJECTIVE: Side crashes between vehicles which usually lead to high casualties and property loss, rank first among total crashes in China. This paper aims to identify the factors associated with injury severity of side crashes at intersections and to provide suggestions for developing countermeasures to mitigate the levels of injuries. METHOD: In order to investigate the role of striking and struck vehicles in side crashes simultaneously, bivariate probit model was proposed and Bayesian approach was employed to evaluate the model, compared to the corresponding univariate probit model. DATA: Crash data from Beijing, China for the period 2009-2012 were used to carry out the statistical analysis. Based on the investigation with vehicles and data analysis on events, 130 intersection side crash cases were selected to form a specific dataset. Then, the influence of human, vehicles, roadway and environmental variables on crash severity was examined by means of bivariate probit regression within Bayesian framework. RESULTS: The effects of the factors on striking vehicle drivers and struck vehicle drivers were considered separately and simultaneously to find more targeted conclusions. The statistical analysis revealed vehicle type, lane number, no non-motorized lane and speeding have the corresponding influence on the injury severity of striking vehicles, while time of day and vehicle type of struck vehicles increased the likelihood of being injured. CONCLUSIONS: From the results it can be concluded that there indeed exists correlation between striking and struck vehicles in side crashes, although the correlation is not so strong. Importantly, Bayesian bivariate probit model can address the role of striking and struck vehicles in side crashes simultaneously and can accommodate the correlation clearly, which extends the range of univariate probit analysis. The general and empirical countermeasures are presented to improve the safety at intersections.


Asunto(s)
Accidentes de Tránsito/estadística & datos numéricos , Heridas y Traumatismos/mortalidad , Teorema de Bayes , Beijing/epidemiología , Entorno Construido/estadística & datos numéricos , Humanos , Modelos Logísticos , Vehículos a Motor/clasificación , Vehículos a Motor/estadística & datos numéricos , Probabilidad
17.
Accid Anal Prev ; 134: 105315, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31668349

RESUMEN

Observed accidents have been the main resource for road safety analysis over the past decades. Although such reliance seems quite straightforward, the rare nature of these events has made safety difficult to assess, especially for new and innovative traffic treatments. Surrogate measures of safety have allowed to step away from traditional safety performance functions and analyze safety performance without relying on accident records. In recent years, the use of extreme value theory (EV) models in combination with surrogate safety measures to estimate accident probabilities has gained popularity within the safety community. In this paper we extend existing efforts on EV for accident probability estimation for two dependent surrogate measures. Using detailed trajectory data from a driving simulator, we model the joint probability of head-on and rear-end collisions in passing maneuvers. We apply the Block Maxima method and estimate several extremal univariate and bivariate models, including the logistic copula. In our estimation we account for driver specific characteristics and road infrastructure variables. We show that accounting for these factors improve the head-on and rear-end collision probabilities estimation. This work highlights the importance of considering driver and road heterogeneity in evaluating related safety events, of relevance to interventions both for in-vehicle and infrastructure-based solutions. Such features are essential to keep up with the expectations from surrogate safety measures for the integrated analysis of accident phenomena, which show to significantly improve from the best known stationary extreme value models.


Asunto(s)
Accidentes de Tránsito/prevención & control , Conducción de Automóvil , Accidentes de Tránsito/estadística & datos numéricos , Entorno Construido , Simulación por Computador , Humanos , Modelos Estadísticos , Probabilidad
18.
Accid Anal Prev ; 134: 105326, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31675667

RESUMEN

Numerous studies have previously used a variety of count-data models to investigate factors that affect the number of crashes over a certain period of time on roadway segments. Unlike past studies which deal with crash frequency, this study views the crash rates directly as a continuous variable left-censored at zero and explores the application of an alternate approach based on tobit regression. To thoroughly investigate the factors affecting freeway crash rates and the potentially temporal instability in the effects of crash factors involving traffic volume, freeway geometries and pavement conditions, a classic uncorrelated random parameters tobit (URPT) model and a correlated random parameters tobit (CRPT) model were estimated, along with a conventional fixed parameters tobit (FPT) model. The analysis revealed a large number of safety factors, including several appealing and interesting factors rarely studied in the past, such as the safety effects of climbing lanes and distance along composite descending grade. The results also showed that the CRPT model was not only able to reflect the heterogeneous effects of various factors, but also able to estimate the underlying interactions among unobserved characteristics, and therefore provide better statistical fit and offer more insights into factors contributing to freeway crashes than its model counterparts. Additionally, the results showed significant temporal instability in CRPT models across the studied time periods indicating that crash factors (including unobserved characteristics and the underlying interactions among them) and their effects on crash rates varied over time, and more attentions should be paid when interpreting crash data-analysis findings and making safety policies. The modeling technique in this study demonstrates the potential of CRPT model as an effective approach to gain new insights into safety factors, particularly when the heterogeneous effects of factors on safety are interactive. Additionally, findings from this study are also expected to assist in developing more effective countermeasures by better understanding the safety effects of factors associated with freeway design characteristics and pavement conditions.


Asunto(s)
Accidentes de Tránsito/estadística & datos numéricos , Entorno Construido/provisión & distribución , Humanos , Modelos Estadísticos , Medición de Riesgo , Seguridad/normas
19.
Accid Anal Prev ; 134: 105316, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31677475

RESUMEN

The present research demonstrates the use of advanced trajectory based data to analyze road user interactions at an un-signalized intersection under heterogeneous traffic complexities. This study demonstrates an improvement over the conventional grid-based analysis to estimate surrogate safety measures (SSM). An advanced pattern-based approach to categorize pedestrian-vehicle interactions based on the road user behavior is proposed in the study. A concept of a two-interaction pattern has been applied, which deals with the responsive and non -responsive behavior of the road users, respectively. The behavior-based patterns were categorized based on the SSM like Speed, Time to Collision, and Gap Time profiles of the pedestrian and vehicle interacting on an un-signalized intersection. On conducting a variable importance test, i.e., k-fold test, it was comprehended that, for pattern-1, Time to collision (TTC), and for pattern-2 both TTC and Post Encroachment Time (PET) were showing required importance. Further, Import Vector Machine (IVM) approach was used to classify the severity levels based on selected indicators computed from 1486 events, occurring at three Un-Signalized intersections in India. The proposed severity levels will help to test and evaluate various infrastructure and control improvements for making urban intersections safe for road users. It was observed from the severity levels of both the patterns that, events involving non-evasive behavior can also result in critical interaction. Overall, the research provides an advanced framework for evaluating and improving the safety of the uncontrolled intersections.


Asunto(s)
Accidentes de Tránsito/prevención & control , Conducción de Automóvil , Planificación Ambiental , Peatones , Automóviles , Entorno Construido , Humanos , India
20.
Accid Anal Prev ; 134: 105297, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31683233

RESUMEN

The motorcyclist is exposed to the risk of falling and impacting ground head-first at a wide range of travelling speeds - from a speed limit of less than 50 km/h on the urban road to the race circuit where speed can reach well above 200 km/h. However, motorcycle helmets today are tested at a single and much lower impact speed, i.e. 30 km/h. There is a knowledge gap in understanding the dynamics and head impact responses at high travelling speeds due to the limitation of existing laboratory rigs. This study used a finite element head model coupled with a motorcycle helmet model to simulate head-first falls at travelling speed (or tangential velocity at impact) from 0 to 216 km/h. The effect of different falling heights (1.6 m and 0.25 m) and coefficient of frictions (0.20 and 0.45) between the helmet outer shell and ground were also examined. The simulation results were analysed together with the analytical model to better comprehend rolling and/or sliding phenomena that are often observed in helmet oblique impacts. Three types of helmet-to-ground interactions are found when the helmet impacts ground from low to high tangential velocities: (1) helmet rolling without slipping; (2) a combination of sliding and rolling; and (3) continuous sliding. The tangential impulse transmitted to the head-helmet system, peak angular head kinematics and brain strain increase almost linearly with the tangential velocity when the helmet rolls but plateaus when the helmet slides. The critical tangential velocity at which the motion transit from the rolling regime to the sliding regime depends on both the falling height and friction coefficient. Typically, for a fall height of 1.63 m and a friction coefficient of 0.45, the rolling/sliding transition occurs at a tangential velocity of 10.8 m/s (38.9 km/h). Low sliding resistance in helmet design, i.e. by the means of a lower friction coefficient between the helmet outer shell and ground, has shown a higher reduction of brain tissue strain in the sliding regime than in the rolling regime. This study uncovers the underlying dynamics of rolling and sliding phenomena in high-speed oblique impacts, which largely affect head impact biomechanics. Besides, the study highlights the importance of testing helmets at speeds covering both the rolling and sliding regime since potential designs for improved head protection at high-speed impacts can be more distinguishable in the sliding regime than in the rolling regime.


Asunto(s)
Fricción , Dispositivos de Protección de la Cabeza , Motocicletas/estadística & datos numéricos , Aceleración , Accidentes de Tránsito/clasificación , Fenómenos Biomecánicos/fisiología , Traumatismos Craneocerebrales/etiología , Traumatismos Craneocerebrales/prevención & control , Humanos , Factores de Riesgo
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