Objective: Real-world driving studies, including those involving speeding alert devices and autonomous vehicles, can gauge an individual vehicle's speeding behavior by comparing measured speed with mapped speed zone data. However, there are complexities with developing and maintaining a database of mapped speed zones over a large geographic area that may lead to inaccuracies within the data set. When this approach is applied to large-scale real-world driving data or speeding alert device data to determine speeding behavior, these inaccuracies may result in invalid identification of speeding. We investigated speeding events based on service provider speed zone data.
Methods: We compared service provider speed zone data (Speed Alert by Smart Car Technologies Pty Ltd., Ultimo, NSW, Australia) against a second set of speed zone data (Google Maps Application Programming Interface [API] mapped speed zones).
Results: We found a systematic error in the zones where speed limits of 50–60 km/h, typical of local roads, were allocated to high-speed motorways, which produced false speed limits in the speed zone database. The result was detection of false-positive high-range speeding. Through comparison of the service provider speed zone data against a second set of speed zone data, we were able to identify and eliminate data most affected by this systematic error, thereby establishing a data set of speeding events with a high level of sensitivity (a true positive rate of 92% or 6,412/6,960).
Conclusions: Mapped speed zones can be a source of error in real-world driving when examining vehicle speed. We explored the types of inaccuracies found within speed zone data and recommend that a second set of speed zone data be utilized when investigating speeding behavior or developing mapped speed zone data to minimize inaccuracy in estimates of speeding. 相似文献
Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters. 相似文献
Kiang, Julie E., J. Rolf Olsen, and Reagan M. Waskom, 2011. Introduction to the Featured Collection on “Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”Journal of the American Water Resources Association (JAWRA) 47(3):433‐435. DOI: 10.1111/j.1752‐1688.2011.00551.x 相似文献
Coastal development and engineering projects preclude ecosystem processes that provide habitat for beach nesting birds. Management
for coastal species may depend on actions that attempt to restore important habitat features and mitigate disturbance effects.
However, species response to restoration or other management actions may be difficult to predict or measure. At Jones Beach
State Park, on Long Island, New York, a 0.49 ha restoration project provided moist substrate foraging habitat for breeding
Piping Plovers (Charadrius melodus) from 2002 to 2005. We examined whether foraging habitat restoration affected Piping Plover breeding population size, productivity,
and fledgling production within 300 m of the restoration site. We found a positive relationship between habitat restoration
and the number of fledglings produced per year. However, foraging habitat restoration did not significantly increase the number
of Plover pairs breeding at Jones Beach. Our ability to evaluate restoration effects on Plovers depended on: 1) use of multiple
performance criteria; 2) a design that allowed comparison of pre- and post-restoration data; and 3) a spatial control that
allowed comparison of similar areas that were near and far from the restoration site. Despite the small size of the restoration
project, there were measurable benefits to Plovers, indicating that foraging habitat restoration may be an effective tool
for species recovery. 相似文献
The P concentration in Norton Creek which drains cultivated Histosols in Quebec showed median concentration exceeding up to 14 times the environmental guideline of 0.03 mg total P L(-1). The aim of this study was to develop environmental and agronomic thresholds using soil tests to provide a tool for P management in Histosols. Soil samples were collected from Histosols across Quebec (82) and in fertilizer trials (66) to calibrate soil test methods against the degree of P saturation (DPS(OX)) using the acid-oxalate method and setting alpha(m) = 0.4, and the water-extractable P (P(W)) (Sissingh, 1971). The field trials on crop response to added P were conducted with carrots (8), potatoes (11), onions (10), Chinese cabbage (7), celery (10), and lettuce (20). Relative yields were computed as yield in control without P divided by highest yield with added P. The Mehlich III (M-III) P extraction was more closely related (r(2) = 0.73) to DPS(OX) than the Bray 1 method (r(2) = 0.62) and the Florida extraction method (r(2) = 0.53). The [P/(Al+gammaFe)](M-III) ratio as index of P saturation (IPS(M-III)) was the most closely related to DPS(OX) (r(2) = 0.88) setting gamma = 5. The critical [P/(Al+5Fe)](M-III) ratio of 0.05 at DPS(OX) = 0.25 and P(W) = 9.7 mg P L(-1) was validated by an independent study from North Carolina. The soil group (low- vs. high-IPS(M-III) soils) significantly influenced crop response to added P. Critical agronomic IPS(M-III) values were found between 0.10 and 0.15. Those environmental and agronomic benchmarks are instrumental for managing the P in vegetable-grown Histosols. 相似文献
As more people visit natural areas for tourism and recreation purposes, it is becoming increasingly important to understand the value they place on these natural resources. Specifically, tourists to Florida have been increasingly interested in visiting natural areas, forests, parks, and preserves-highlighting the importance of this new and growing phenomenon. We analyze visitors' demand for nature-based recreation in the Apalachicola River region of Florida using the travel cost method. The results from a count data regression model reveal that on average visitors would pay 74.18 dollars per visit-day for nature-based recreation resulting in a total economic value of 484.56 million dollars attributable to nature-based recreation in the Apalachicola River region. Results of this study provide useful information for natural resources management in the region and a rationale to preserve Florida's unique ecosystems. 相似文献
Watercraft collisions account for 25–30% of manatee deaths annually in Florida. Education and outreach interventions for boaters
are strategies for reducing manatee mortality. We evaluated the effectiveness of the Manatee Watch program by surveying primary
boat users whose boats were approached by Manatee Watch. We compared the attitudes, knowledge, and behavioral intentions of
boaters who received Manatee Watch materials with a control group of boaters observed by the Florida Marine Research Institute
in Tampa Bay during 1999–2001. Results of the 51-item telephone survey with 499 boaters indicated that the Manatee Watch intervention
had little effect on boater’s attitudes, knowledge, and behaviors regarding manatees. However, individual attitude scores
were positively correlated with safe boating behaviors in shallow waters including maintaining a slower speed and watching
out for manatees. Overall knowledge about manatees was correlated with one manatee-safe boating behavior. To improve efficacy,
educators should (a) incorporate evaluation into the planning stages of program development; (b) target messages to influence
boaters’ attitudes toward manatees and ecosystem health, and their feelings of ownership and empowerment; (c) facilitate active
participation of the boaters; and (d) increase the duration and variety of intervention. 相似文献
Food and Environmental Virology - Bacterial biofilms contribute to contamination, spoilage, persistence, and hygiene failure in the food industry, but relatively little is known about the behavior... 相似文献