Fatal crash between a car operating with automated control systems and a tractor-semitrailer truck

Abstract

Objective: The objective of this investigation was to evaluate the interaction between an SAE level 2 automated vehicle and the driver, including the limitations imposed by the vehicle on the driver.

Methods: A case study of the first fatal crash involving a vehicle operating with an automated control system was performed using scene evidence, vehicle damage, and recorded data available from the vehicle, and information from both drivers, including experience, phone records, computer systems, and medical information, was reviewed.

Results: System performance data downloaded from the car indicated that the driver was operating it using the Traffic-Aware Cruise Control and Autosteer lane-keeping systems, which are automated vehicle control systems within Tesla’s Autopilot suite. As the car crested the hill, a tractor trailer began its left turn onto a crossing roadway. Although reconstruction of the crash determined that there was sufficient sight distance for both drivers to see each other and take action, neither responded to the circumstances leading to the collision. Further, based on the speeds of the vehicles and simulations of the truck’s path, the car driver had at least 10.4?s to detect the truck and take evasive action. Neither the car driver nor the Autopilot system changed the vehicle’s velocity.

?At the time of the crash, the system performance data indicated that the last driver interaction with the system was 1?min 51?s prior when the cruise control speed was set to 74?mph. The driver was operating the vehicle using the Autopilot system for 37 of the 41?min in the last trip. During this period, the vehicle detected the driver’s hands on the steering wheel for a total of 25?s; each time his hands were detected on the wheel was preceded by a visual alert or auditory warning.

Conclusions: The National Transportation Safety Board (NTSB) determined that the probable cause of the Williston, Florida, crash was the truck driver’s failure to yield the right of way to the car, combined with the car driver’s inattention due to overreliance on vehicle automation, which resulted in the car driver’s lack of reaction to the presence of the truck. Contributing to the car driver’s overreliance on the vehicle automation was the car’s operational design, which permitted the driver’s prolonged disengagement from the driving task and his use of the automation in ways inconsistent with guidance and warnings from the manufacturer.     

Estimating Root Zone Soil Moisture at Continental Scale Using Neural Networks

This study investigates the feasibility of artificial neural networks (ANNs) to retrieve root zone soil moisture (RZSM) at the depths of 20 cm (SM20) and 50 cm (SM50) at a continental scale, using surface information. To train the ANNs to capture interactions between land surface and various climatic patterns, data of 557 stations over the continental United States were collected. A sensitivity analysis revealed that the ANNs were able to identify input variables that directly affect the water and energy balance in root zone. The data important for RZSM retrieval in a large area included soil texture, surface soil moisture, and the cumulative values of air temperature, surface soil temperature, rainfall, and snowfall. The results showed that the ANNs had high skill in retrieving SM20 with a correlation coefficient above 0.7 in most cases, but were less effective at estimating SM50. The comparison of the ANNs showed that using soil texture data improved the model performance, especially for the estimation of SM50. It was demonstrated that the ANNs had high flexibility for applications in different climatic regions. The method was used to generate RZSM in North America using Soil Moisture and Ocean Salinity (SMOS) soil moisture data, and achieved a spatial soil moisture pattern comparable to that of Global Land Data Assimilation System Noah model with comparable performance to the SMOS surface soil moisture retrievals. The models can be efficient alternatives to assimilate remote sensing soil moisture data for shallow RZSM retrieval.     

利用CFSR数据开展海上风电场长年代风能资源评估

开展长年代风能资源评估可为海上风电场的可行性研究和风险评估提供依据和支撑。创新性地引入了气候预测系统再分析(CFSR)数据,以江苏响水海上风电场为例开展了长年代风能资源评估,结果表明:CFSR数据10 m高度风速与海上气象塔10 m高度风速的平均偏差为-0.2 m·s~(-1),均方根误差为1.9 m·s~(-1);CFSR数据10 m高度风速与海上气象塔90 m高度风速的相关系数范围在0.359~0.619,相比气象站的相关系数提高了40%~90%;长年代订正得到海上气象塔90 m高度近30 a的风数据,多年平均风速为6.9 m·s~(-1),标准差为0.2 m·s~(-1)(2.9%);测算出海上风电场近30年的等效满负荷小时数,多年平均值为2 423 h,标准差为112 h(4.6%);评估出25 a一遇(海上风电场的寿命期)、10 a一遇、5 a一遇的最小年平均风速分别为6.6、6.7和6.8 m·s~(-1),最小年等效满负荷小时数分别为2 227、2 280和2 329 h。利用CFSR数据开展海上风电场长年代风能资源评估在技术上是可行的。     

Water scarcity and rioting: Disaggregated evidence from Sub-Saharan Africa

It is often purported that unusually dry weather conditions provoke small-scale social conflict—riots—by intensifying the competition for water. The present paper explores this hypothesis, using data from Sub-Saharan Africa. We rely on monthly data at the cell level (0.5×0.5 degrees), an approach that is tailored to the short-lived and local nature of the phenomenon. Using a drought index to proxy for weather shocks, we find that a one-standard-deviation fall in the index (signaling drier conditions) raises the likelihood of riots in a given cell and month by 8.3%. We further observe that the effect of unusually dry weather conditions is substantially larger in cells with a lower availability of water resources (such as rivers and lakes), a finding that supports the significance of the competition-for-water mechanism.     

Evaluating the aesthetic value of cultural ecosystem services by mapping geo-tagged photographs from social media data on Panoramio and Flickr

Traditional approaches for evaluating aesthetic value rely on surveys or interviews. Social media provides a new type of crowdsourcing data to examine the relationships between aesthetic value and citizens' activities. The main goal of this paper was to evaluate aesthetic value in Nebraska by using citizen-reported geo-tagged photographs posted on two social media sites – Panoramio and Flickr. The study used the application programming interface from Panoramio and Flickr to obtain the latitude and longitude of the geo-tagged photographs, and then used ArcGIS spatial statistical tools to examine spatial patterns with areas of aesthetic value in Nebraska. The outcomes identified the clusters of pictures with the locations of ecosystem service provisioning areas of aesthetic value in Nebraska, identified new areas with aesthetic value, and drew comparisons with local and regional population distribution. This study provided an innovative approach to using crowdsourcing data to verify the value of ecosystem services.     

微小卫星动力学环境试验及其数据处理

以上海微小卫星工程中心与复旦大学力学与工程科学系共同合作的微小卫星动力学试验研究项目作为背景,主要通过某真实型号微小卫星的振动环境试验和结构模态试验来介绍微小卫星环境试验技术和试验响应数据的处理方法。     

南京市在长江大保护工作中推进生态环境大数据融合的思考

以习近平长江经济带发展思路和实施国家大数据战略为背景,简要介绍了南京市长江大保护和大数据融合工作的现状与特点。在对标分析武汉市长江大保护和贵州省大数据融合先进工作经验的基础上,针对当前南京市大数据应用水平不高,难以为生态环境重要决策提供有效支撑的情况,从树立创新思维摸清沿江污染底数、树立法治思维推进大数据融合共享、树立融入思维推进社会化服务、树立数字思维适应信息化和“互联网+”发展等方面,对南京市如何深度整合利用现有大数据资源,构建具有南京特色的长江大保护“生态眼”监管系统提出对策和建议。     

A Statistical Assessment of Changes in Precipitation Chemistry at CAPMoN Sites, Canada

The objective of this study is to decide if chemical concentrations measured during 1988-1997in precipitation by the Canadian Air and Precipitation Monitoring Network (CAPMoN) indicate changes in the annual patterns. The inference is based on SO₄, NO₃, Cl,NH₄, Na, Ca and K concentrations monitored daily with the rain water acidity pH. By pattern is understood the probability distribution of the annual sample at a particular location. Most of the annual data can be well described by means of a linear regression model with second order polynomial trend and autocorrelated noise. Statistical analysis based on the model shows luck of systematic significant year to year increases or declines of the concentrations.     

国控重点污染源监督监测数据QA/QC量化评估体系探讨

阐述了建立国控重点污染源监督监测数据质量QA/QC量化评估体系的重要性和迫切性,从国控污染源QA/QC量化评估体系建设的基本思路、量化评估指标的组成、量化评估指标的权重及QL阈值等方面,对国控重点污染源监督监测数据质量QA/QC量化评价体系的建立进行探讨。     

国家污染源监测数据管理系统构建

针对全国污染源监测数据管理和应用需求,设计了一套污染源监测数据指标集,分析了污染源排放达标评价对象及评价结果表征方法,突破了建立电子化排放标准库、数据录入全过程多层次质量控制等关键技术,并在需求分析、功能设计和技术方案选择的基础上,开发了覆盖国家、省、市3级应用的污染源监测数据管理信息软件平台,取得了很好的应用效果。