Search Results (2)

Traffic congestion not only affects traffic flow but also influences public perception of congested regions. While analyzing congestion at the road section level can help identify engineering solutions, it often fails to reveal broader spatial patterns and trends at the regional or macro scale unless summarized effectively. This study aims to address these challenges by focusing on regional-scale traffic congestion amounts measured by distanceTime metrics. A 12–month dataset, sampled every 10 min, was analyzed to identify spatial patterns, temporal trends, regional variations, and predictive models in the Metro Atlanta area. The results show that congestion is the most severe and increasing at key urban corridors like Brookhaven–Sandy Springs, the downtown connector, Druid Hills–Decatur, and Johns Creek–Cumming, aligning with recent urban developments. Cities such as Alpharetta, Dunwoody, Brookhaven, Austell, Stone Mountain, East Point, Lake City, Morrow, Fairburn, and Jonesboro show high increasing trends in congestion. Predictive modeling with the long short-term memory (LSTM) method shows promising results for short-term forecasts, though variability in data requires further optimization for certain cities. This research is significant because it demonstrates that congestion amounts measured by distanceTime metrics can be used for assessing regional characteristics broadly at a metropolitan city scale. The findings and methodologies identified in this research might support urban and transportation planning efforts in metropolitan planning organizations, such as the Atlanta Regional Commission, by identifying congestion amounts and trends at both the regional and road scales. Full article

Fly ash consists of mainly silt-size spherules that form during high-temperature coal combustion, such as in steam locomotives and coal-burning power plants. In the eastern USA, fly ash was distributed across the landscape atmospherically beginning in the late 19th century, peaking in the mid-20th century, and decreasing sharply with implementation of late 20th century particulate pollution controls. Although atmospheric deposition is limited today, fly ash particles continue to be resedimented into alluvial and lacustrine deposits from upland soil erosion and failure of fly ash storage ponds. Magnetic fly ash is easily extracted and identified microscopically, allowing for a simple and reproducible method for identifying post-1850 CE (Common Era) alluvium and lacustrine sediment. In the North Carolina Piedmont, magnetic fly ash was identified within the upper 50 cm at each of eight alluvial sites and one former milldam site. Extracted fly ash spherules have a magnetite or maghemite composition, with substitutions of Al, Si, Ca, and Ti, and range from 3–125 µm in diameter (mainly 10–45 µm). Based on the presence of fly ash, post-1850 alluvial deposits are 15–45 cm thick in central North Carolina river valleys (<0.5 km wide), ~60% thinner than in central Illinois valleys of similar width. Slower sedimentation rates in North Carolina watersheds are likely a result of a less agricultural land and less erodible (more clayey) soils. Artificial reservoirs (Lake Decatur, IL) and milldams (Betty’s Mill, NC), provide chronological tests for the fly ash method and high-resolution records of anthropogenic change. In cores of Lake Decatur sediments, changes in fly ash content appear related to decadal-scale variations in annual rainfall (and runoff), calcite precipitation, land-use changes, and/or lake history, superimposed on longer-term trends in particulate pollution. Full article