【目的】对城市交叉口采用的左转非机动车信号灯设施进行交通安全性量化评估。【方法】提出一种基于拓展碰撞时间(extended time to collision,ETTC)指标的左转非机动车信号灯安全效应评估方法。针对现有的碰撞时间(time to collision,T...【目的】对城市交叉口采用的左转非机动车信号灯设施进行交通安全性量化评估。【方法】提出一种基于拓展碰撞时间(extended time to collision,ETTC)指标的左转非机动车信号灯安全效应评估方法。针对现有的碰撞时间(time to collision,TTC)指标不适于评估交叉口左转非机动车冲突的问题,考虑非机动车车辆尺寸与加速度对交通冲突的影响,采用拓展碰撞时间指标,评估交叉口非机动车交通冲突。收集长沙市4个信号交叉口的视频大数据,利用视频软件Tracker提取车辆微观轨迹后,开展案例分析。【结果】左转非机动车信号灯在时间上明确了非机动车的通行权,其设置能显著降低非机动车冲突率,在平峰、高峰时段非机动车冲突率分别降低了40.11%、25.27%。在直行相位末期、左转相位即将启亮时,设置组的左转非机动车在待行区等待,冲突率降为0;而对比组近50%的非机动车违规左转,冲突严重。设置左转非机动车信号灯的改善效果随非机动车流量的增大呈先增加后降低趋势,而随机动车流量的增大呈逐步波动下降趋势。【结论】本研究揭示了非机动车左转信号灯的设置对减少交叉口交通冲突的影响,可为城市交叉口非机动车交通安全管控提供有益参考。展开更多
选取长沙市中心区4个典型信号交叉口,利用视频轨迹追踪软件,提取右转机动车与直行非机动车的冲突交通流轨迹数据。以减速、换道等避险行为与可能发生碰撞(距离碰撞点时间小于2 s)为依据,采集机非冲突样本;选择距离碰撞最大时间(MTTC)和...选取长沙市中心区4个典型信号交叉口,利用视频轨迹追踪软件,提取右转机动车与直行非机动车的冲突交通流轨迹数据。以减速、换道等避险行为与可能发生碰撞(距离碰撞点时间小于2 s)为依据,采集机非冲突样本;选择距离碰撞最大时间(MTTC)和冲突时间差(TDTC)作为评价指标,提出一种基于交通流运行轨迹的改进型TTC(Time to Collision)法的机非冲突判别方法。选择某实例交叉口,分别采用TTC法、改进型TTC法和后侵入时间(PET)法,评估得到右转机动车与直行非机动车的冲突数,分别为7,24,22次。结果表明,传统的TTC法低估了交叉口的机非冲突水平,改进型TTC法的判别准确率提高了2.14倍,证明了方法的可行性。展开更多
BACKGROUND Blunt aortic injury is a special type of aortic disease.Due to its low incidence,high prehospital mortality and high probability of leakage diagnosis,the timely identification of patients with blunt aortic ...BACKGROUND Blunt aortic injury is a special type of aortic disease.Due to its low incidence,high prehospital mortality and high probability of leakage diagnosis,the timely identification of patients with blunt aortic injury who survive the initial injury has always been a clinical challenge.CASE SUMMARY We report a case of traumatic aortic pseudoaneurysm with right iliac artery dissection aneurysm that was diagnosed 3 mo after a traffic accident.The patient is a 76-year-old male who was knocked down by a fast-moving four-wheel motor vehicle while crossing the road(the damage mechanism was side impact).He received chest,cranial computed tomography(CT)and whole abdomen enhanced CT in the local hospital.The images suggested subarachnoid hemorrhage,right frontoparietal scalp hematoma,fracture of the right clavicle and second rib,lumpshaped mediastinal shadow outside the anterior descending thoracic aorta(mediastinal hematoma),mesenteric vascular injury with hematoma formation,pelvic fracture,and subluxation of the left sacroiliac joint.After the pelvic fracture was fixed with an external stent,he was sent to our hospital for further treatment.In our hospital,he successfully underwent partial resection of the small intestine and CT-guided screw internal fixation of the left sacroiliac joint and returned to the local hospital for rehabilitation treatment.However,since the accident,the patient has been suffering from mild chest pain,which has not aroused the attention of clinicians.During rehabilitation,his chest pain gradually worsened,and the thoracic aorta computed tomography angiography performed in the local hospital showed a pseudoaneurysm in the initial descending segment of the aortic arch.After transfer to our hospital,a dissecting aneurysm of the right external iliac artery was incidentally found in the preoperative evaluation.Finally,endovascular stent graft repair was performed,and he was discharged on the 10th day after the operation.No obvious endo-leak was found after 4 years of follow-up.CONCLUSION We highlight that emergency trauma centers should consider the possibility of aortic injury in patients with severe motor vehicle crashes and repeat the examination when necessary to avoid missed diagnoses.展开更多
The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. I...The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. It included 768 patients admitted to SQUH general surgery department following BAT. 43 patients with splenic injury were identified (34 males, 9 females). The mean age of patients with splenic injury was 36.0 years (34.4 years for males, 42.1 years for females). The most common mechanism of injury was motor vehicle collision (90.7%). Grade I, II are the most common grades of splenic injury. Non-Omani patients accounted for (51.2%) and most of them were pedestrians at the time of trauma. Ribs fracture is the most common injury associated with splenic injury. 36 (83.7%) patients were managed conservatively and 7 (16.3%) patients were splenectomized. Angioembolization was done for 11 (30.6%) patients. Despite the small population of Oman, high incidence of motor vehicle collision (MVC) increases the incidence of splenic injury among young age group.展开更多
文摘【目的】对城市交叉口采用的左转非机动车信号灯设施进行交通安全性量化评估。【方法】提出一种基于拓展碰撞时间(extended time to collision,ETTC)指标的左转非机动车信号灯安全效应评估方法。针对现有的碰撞时间(time to collision,TTC)指标不适于评估交叉口左转非机动车冲突的问题,考虑非机动车车辆尺寸与加速度对交通冲突的影响,采用拓展碰撞时间指标,评估交叉口非机动车交通冲突。收集长沙市4个信号交叉口的视频大数据,利用视频软件Tracker提取车辆微观轨迹后,开展案例分析。【结果】左转非机动车信号灯在时间上明确了非机动车的通行权,其设置能显著降低非机动车冲突率,在平峰、高峰时段非机动车冲突率分别降低了40.11%、25.27%。在直行相位末期、左转相位即将启亮时,设置组的左转非机动车在待行区等待,冲突率降为0;而对比组近50%的非机动车违规左转,冲突严重。设置左转非机动车信号灯的改善效果随非机动车流量的增大呈先增加后降低趋势,而随机动车流量的增大呈逐步波动下降趋势。【结论】本研究揭示了非机动车左转信号灯的设置对减少交叉口交通冲突的影响,可为城市交叉口非机动车交通安全管控提供有益参考。
文摘选取长沙市中心区4个典型信号交叉口,利用视频轨迹追踪软件,提取右转机动车与直行非机动车的冲突交通流轨迹数据。以减速、换道等避险行为与可能发生碰撞(距离碰撞点时间小于2 s)为依据,采集机非冲突样本;选择距离碰撞最大时间(MTTC)和冲突时间差(TDTC)作为评价指标,提出一种基于交通流运行轨迹的改进型TTC(Time to Collision)法的机非冲突判别方法。选择某实例交叉口,分别采用TTC法、改进型TTC法和后侵入时间(PET)法,评估得到右转机动车与直行非机动车的冲突数,分别为7,24,22次。结果表明,传统的TTC法低估了交叉口的机非冲突水平,改进型TTC法的判别准确率提高了2.14倍,证明了方法的可行性。
文摘BACKGROUND Blunt aortic injury is a special type of aortic disease.Due to its low incidence,high prehospital mortality and high probability of leakage diagnosis,the timely identification of patients with blunt aortic injury who survive the initial injury has always been a clinical challenge.CASE SUMMARY We report a case of traumatic aortic pseudoaneurysm with right iliac artery dissection aneurysm that was diagnosed 3 mo after a traffic accident.The patient is a 76-year-old male who was knocked down by a fast-moving four-wheel motor vehicle while crossing the road(the damage mechanism was side impact).He received chest,cranial computed tomography(CT)and whole abdomen enhanced CT in the local hospital.The images suggested subarachnoid hemorrhage,right frontoparietal scalp hematoma,fracture of the right clavicle and second rib,lumpshaped mediastinal shadow outside the anterior descending thoracic aorta(mediastinal hematoma),mesenteric vascular injury with hematoma formation,pelvic fracture,and subluxation of the left sacroiliac joint.After the pelvic fracture was fixed with an external stent,he was sent to our hospital for further treatment.In our hospital,he successfully underwent partial resection of the small intestine and CT-guided screw internal fixation of the left sacroiliac joint and returned to the local hospital for rehabilitation treatment.However,since the accident,the patient has been suffering from mild chest pain,which has not aroused the attention of clinicians.During rehabilitation,his chest pain gradually worsened,and the thoracic aorta computed tomography angiography performed in the local hospital showed a pseudoaneurysm in the initial descending segment of the aortic arch.After transfer to our hospital,a dissecting aneurysm of the right external iliac artery was incidentally found in the preoperative evaluation.Finally,endovascular stent graft repair was performed,and he was discharged on the 10th day after the operation.No obvious endo-leak was found after 4 years of follow-up.CONCLUSION We highlight that emergency trauma centers should consider the possibility of aortic injury in patients with severe motor vehicle crashes and repeat the examination when necessary to avoid missed diagnoses.
文摘The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. It included 768 patients admitted to SQUH general surgery department following BAT. 43 patients with splenic injury were identified (34 males, 9 females). The mean age of patients with splenic injury was 36.0 years (34.4 years for males, 42.1 years for females). The most common mechanism of injury was motor vehicle collision (90.7%). Grade I, II are the most common grades of splenic injury. Non-Omani patients accounted for (51.2%) and most of them were pedestrians at the time of trauma. Ribs fracture is the most common injury associated with splenic injury. 36 (83.7%) patients were managed conservatively and 7 (16.3%) patients were splenectomized. Angioembolization was done for 11 (30.6%) patients. Despite the small population of Oman, high incidence of motor vehicle collision (MVC) increases the incidence of splenic injury among young age group.
