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.     

Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca–HCO₃ or Ca (Mg)–HCO₃ type in karst groundwater to the Ca–Cl (+ NO₃) or Ca (Mg)–Cl (+ NO₃), and Ca–Cl (+ NO₃ + SO₄) or Ca (Mg)–Cl (+ NO₃ + SO₄) type, indicating increases in NO₃⁻, Cl⁻ and SO₄²⁻ concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water–rock interaction in the limestone-dominated system; and (c) water–rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water–rock interaction) was the primary source of Ca²⁺ and HCO₃⁻ in groundwater, water–rock interaction in dolomite-dominated system resulted in higher Mg²⁺ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl⁻, NO₃⁻, SO₄²⁻, Na⁺ and K⁺ to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities played the most important role, however.     

The gas/particle partitioning of polycyclic aromatic hydrocarbons collected at a sub-Arctic site in Canada

Polycyclic aromatic hydrocarbons (PAH) were measured in air samples at a remote air monitoring site established in the Yukon Territory, Canada as part of a global project (International Polar Year; IPY) to study the potential for atmospheric long-range transport of anthropogenic pollutants to the Arctic. Gas- and particle-phase PAH were collected in polyurethane foam plugs and on glass fibre filters respectively from August 2007 to October 2009. PAH concentrations were found to be highest in the winter months and lowest in summer. The gas/particle partitioning coefficients of 3–5 ringed PAH were computed and seasonal averages were compared. In the summer time, lower molecular mass PAH exhibited relatively higher partitioning into the particle-phase. This particle-phase partitioning led to the shallowest slopes being recorded during summer for the log–log correlation plots between the PAH partition coefficients and their sub-cooled vapour pressures. Air mass back trajectories suggest that local impacts may be more important during the summer time which is marked by increased camping activities at camping sites in the proximity of the sampling station. In conclusion, both summer and wintertime variations in PAH concentrations and gas/particle partitioning are considered to be source- and phototransformation-dependent rather than dependent on temperature-driven shifts in equilibrium partitioning.     

Measurements of groundwater velocity in discrete rock fractures

Estimating groundwater velocity in fracture networks using a Darcy or cubic law calculation is complicated by the wide distribution of fracture aperture often found in these systems and by the difficulty in measuring hydraulic head in discrete fracture features. Although difficult to conduct in a fractured rock setting, the point dilution method can be utilized to collect direct measurements of groundwater velocity in individual fractures. To compare measured against calculated velocities, more than 100 point dilution experiments were conducted within a 35 x 35 m area of a single fracture and in discrete fracture features within a fracture network at a larger scale. The dilution experiments were conducted by isolating a fracture feature in a borehole, measuring the hydraulic aperture, and measuring the decay of an injected tracer due to the advective groundwater flux across the fracture. Groundwater velocity was estimated using the hydraulic aperture and the rate of decay of the injected tracer. Estimates of the local hydraulic gradient were calculated via the cubic law using the velocity estimate and the hydraulic aperture. The results of the tests conducted in the single fracture show variable (1 to 33 m/day) but on average higher velocities in comparison to that measured during a natural gradient tracer experiment conducted previously (in which the effects of matrix diffusion were accounted for) and to that which would be calculated using the cubic law. Based on these results, it was determined that the best estimate of the average groundwater velocity, at the scale of the measurement area used for the cubic law calculations, could only be obtained using the largest apertures in the aperture distribution. Variability of the velocity measurements was also observed over time. Increases in velocity were attributed to the effect of rainfall although concurrent increases in hydraulic gradient were not detected (likely within the tolerance of the measuring devices). The groundwater velocities measured in the fracture network varied over a wider range than at the scale of the single fracture (from 2 to 388 m/day). No correlation, however, was observed between the size of the fracture aperture and measured velocity.     

Lead speciation in indoor dust: a case study to assess old paint contribution in a Canadian urban house

Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380–2,920 mg Pb kg⁻¹) and dust (200–1,000 mg Pb kg⁻¹) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 μm house dust samples. In the dust fraction <36 μm, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.     

Postnatal nutrition influences male attractiveness and promotes plasticity in male mating preferences

The fossil record of Late Cretaceous–Paleogene modern birds in the Southern Hemisphere includes the Maastrichtian Neogaeornis wetzeli from Chile, Polarornis gregorii and Vegavis iaai from Antarctica, and Australornis lovei from the Paleogene of New Zealand. The recent finding of a new and nearly complete Vegavis skeleton constitutes the most informative source for anatomical comparisons among Australornis, Polarornis, and Vegavis. The present contribution includes, for the first time, Vegavis, Polarornis, and Australornis in a comprehensive phylogenetic analysis. This analysis resulted in the recognition of these taxa as a clade of basal Anseriformes that we call Vegaviidae. Vegaviids share a combination of characters related to diving adaptations, including compact and thickened cortex of hindlimb bones, femur with anteroposteriorly compressed and bowed shaft, deep and wide popliteal fossa delimited by a medial ridge, tibiotarsus showing notably proximally expanded cnemial crests, expanded fibular crest, anteroposterior compression of the tibial shaft, and a tarsometatarsus with a strong transverse compression of the shaft. Isolated bones coming from the Cretaceous and Paleogene of South America, Antarctica, and New Zealand are also referred to here to Vegaviidae and support the view that these basal anseriforms were abundant and diverse at high southern latitudes. Moreover, vegaviids represent the first avian lineage to have definitely crossed the K–Pg boundary, supporting the idea that some avian clades were not affected by the end Mesozoic mass extinction event, countering previous interpretations. Recognition of Vegaviidae indicates that modern birds were diversified in southern continents by the Cretaceous and reinforces the hypothesis indicating the important role of Gondwana for the evolutionary history of Anseriformes and Neornithes as a whole.

     

Inputs of nutrients and fecal bacteria to freshwaters from irrigated agriculture: case studies in Australia and New Zealand

Increasing demand for global food production is leading to greater use of irrigation to supplement rainfall and enable more intensive use of land. Minimizing adverse impacts of this intensification on surface water and groundwater resources is of critical importance for the achievement of sustainable land use. In this paper we examine the linkages between irrigation runoff and resulting changes in quality of receiving surface waters and groundwaters in Australia and New Zealand. Case studies are used to illustrate impacts under different irrigation techniques (notably flood and sprinkler systems) and land uses, particularly where irrigation has led to intensification of land use. For flood irrigation, changes in surface water contaminant concentrations are directly influenced by the amount of runoff, and the intensity and kind of land use. Mitigation for flood irrigation is best achieved by optimizing irrigation efficiency. For sprinkler irrigation, leaching to groundwater is the main transport path for contaminants, notably nitrate. Mitigation measures for sprinkler irrigation should take into account irrigation efficiency and the proximity of intensive land uses to sensitive waters. Relating contaminant concentrations in receiving groundwaters to their dominant causes is often complicated by uncertainty about the subsurface flow paths and the possible pollutant sources, viz. drainage from irrigated land. This highlights the need for identification of the patterns and dynamics of surface and subsurface waters to identify such sources of contaminants and minimize their impacts on the receiving environments.     

A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids

The Cretaceous Carcharodontosauridae is the latest clade of carnosaurs, including the largest predatory dinosaurs yet recorded. Albeit spectacular for their size, the skeletal anatomy of these theropods remains poorly-known, and their diversity was until recently restricted to two Cenomanian species: the highly derived Giganotosaurus carolinii, from southern South America, and the incompletely known Carcharodontosaurus saharicus, from northern Africa. Here we describe an older and basal member of the group, Tyrannotitan chubutensis gen. et sp. nov., from Aptian strata of Patagonia, Argentina. The new taxon gives new insights into the systematics and evolution of carcharodontosaurids and offers a better understanding of the evolution of Southern theropod faunas. We suggest that carcharodontosaurids radiated in Gondwana sharing with spinosaurids the role of top-predators until their extinction in Cenomanian–Turonian times. During this interval, the diplodocoid sauropods and giant titanosaurians went extinct (probably as part of a global-scale crisis), and the smaller abelisaurid theropods took dominance, reigning until the end of the Cretaceous. Electronic Supplementary Material is available.Electronic Supplementary Information  Supplementary material is available for this article at