Field effectiveness evaluation of advanced driver assistance systems

Abstract

Objective: Advanced driver assistance systems (ADAS) are a class of vehicle technologies designed to increase safety by providing drivers with timely warnings and autonomously intervening to avoid hazardous situations. Though laboratory testing suggests that ADAS technologies will greatly impact crash involvement rates, real-world evidence that characterizes their effectiveness is still limited. This study evaluates and quantifies the association of ADAS technologies with the likelihood of a moderate or severe crash for new-model BMWs in the United States.

Methods: Vehicle ADAS option information for the cohort of model year 2014 and later BMW passenger vehicles sold after January 1, 2014 (n?=?1,063,503), was coded using VIN-identified options data. ADAS technologies of interest include frontal collision warning with autonomous emergency braking, lane departure warning, and blind spot detection. BMW Automated Crash Notification system data (from January 2014 to November 2017) were merged with vehicle data by VIN to identify crashed vehicles (n?=?15,507), including date, crash severity (delta V), and area of impact. Using Cox proportional hazards regression modeling, the study calculates the adjusted hazard ratio for crashing among BMW passenger vehicles with versus without ADAS technologies. The adjusted percentage reduction in moderate and severe crashes associated with ADAS is interpreted as one minus the hazard ratio.

Results: Vehicles equipped with both autonomous emergency braking and lane departure warning were 23% less likely to crash than those not equipped (hazard ratio [HR]?=?0.77; 95% confidence interval [CI], 0.73–0.81), controlling for model year, vehicle size and body type. Autonomous emergency braking and lane departure warning generally occur together, making it difficult to tease apart their individual effects. Blind spot detection was associated with a 14% reduction in crashes after controlling for the presence of autonomous emergency braking and lane departure warning (HR =0.86; 95% CI, 0.744–0.99). Differences were observed by vehicle type and crash type. The combined effect of autonomous emergency braking and lane departure warning was greater in newer model vehicles: Equipped vehicles were 13% less likely to crash (HR =0.87; 95% CI, 0.79–0.95) among 2014 model year vehicles versus 34% less likely to crash (HR =0.66; 95% CI, 0.57–0.77) among 2017 model year vehicles.

Conclusion: This robust cohort study contributes to the growing evidence on the effectiveness of ADAS technologies.     

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The Truth about Public Health Protection and Community Sewerage and Water Supply Sanitation in Developing Countries

Since the establishment, following World War II, of the World System, by which the affluent industrialized countries established various international assistance agencies (including the multilateral development banks, UN affiliates, and Bilaterals), these assistance agencies have invested very large sums in helping finance planning and construction of community sewerage and water supply facilities in the developing countries. However, much of this large investment has been ineffective and wasted, primarily because of the lack of understanding by the staff of the assistance agencies that the design criteria for the facilities must be modified to suit the socio-economic status of the developing country. The developing countries are relatively very poor in terms of available finances, hence cannot afford to emulate Western environmental standards and design practices, especially as related to operation and maintenance, hence much simpler approaches must be used. Experiences in several Asian countries are discussed, and a recommendation is made on how to go about resolving this problem.     

Modelling the resilience of Australian savanna systems to grazing impacts.

Savannas occur across all of northern Australia and are extensively used as rangelands. A recent surge in live cattle exports to Southeast Asia has caused excessive grazing impacts in some areas, especially near watering points. An important ecological and management question is "how resilient are savanna ecosystems to grazing disturbances?" Resilience refers to the ability of an ecosystem to remain in its current state (resist change) and return to this state (recover) if disturbed. Resilience responses can be measured using field data. These responses can then be modelled to predict the likely resistance and recovery of savannas to grazing impacts occurring under different climatic conditions. Two approaches were used to model resilience responses. First, a relatively simple mathematical model based on a sigmoid response function was used. This model proved useful for comparing the relative resilience of different savanna ecosystems, but was limited to ecosystems and conditions for which data were available. Second, a complex process model, SAVANNA, was parameterised to simulate the structure and function of Australian savannas. Simulations were run for 50 years at two levels of grazing to evaluate resistance and then for another 50 years with no grazing to evaluate recovery. These runs predicted that savanna grasslands were more resistant to grazing (changed less) than red-loam woodlands, which recovered relatively slowly from grazing impacts. The SAVANNA model also predicted that these woodlands would recover slightly slower under the climate change scenario projected for northern Australia.