Reliability of police-reported information for determining crash and injury severity

Posted speed limit and police-reported injury codes are commonly used by researchers to approximate vehicle impact and occupant injury severity. In-depth crash investigations, however, produce more precise measures of crash and injury severity: change in velocity (delta-V) for crash severity and Abbreviated Injury Scale (AIS) scores for injury severity. A comparison of data from police crash reports with that gathered by National Automotive Sampling System (NASS) investigators highlighted the inadequacy of speed limit and police injury codes as proxies for delta-V and AIS injury severity. In general, delta-V increased with speed limit and higher values of AIS were associated with higher police-coded injury severity, but there were a number of anomalies. In particular, 49% of the drivers coded by police as having incapacitating injuries actually had sustained no more than minor injuries. This overstatement of injury severity was less frequent among male (44%) and elderly (37%) drivers than among female (53%) and nonelderly (50%) drivers. Also, 79% of the investigated vehicles that crashed on roads posted at 60 mph (96 km/h) or higher experienced a delta-V less than 25 mph (40 km/h). Safety studies depending on data from only police reports to establish injury or crash severity therefore could produce erroneous results.     

Findings from long-term monitoring studies at MSW landfill facilities with leachate recirculation

This paper presents findings from long-term monitoring studies performed at full-scale municipal solid waste landfill facilities with leachate recirculation. Data from two facilities at a landfill site in Delaware, USA were evaluated as part of this study: (1) Area A/B landfill cells; and (2) two test cells (one with leachate recirculation and one control cell). Data from Area A/B were compared with proposed waste stability criteria for leachate quality, landfill gas production, and landfill settlement. Data from the test cells were directly compared with each other. Overall, the trends at Area A/B pointed to the positive effects (i.e., more rapid waste degradation) that may be realized through increasing moisture availability in a landfill relative to the reported behavior of more traditionally operated (i.e., drier) landfills. Some significant behavioral differences between the two test cells were evident, including dissimilarities in total landfill gas production quantity and the extent of waste degradation observed in recovered time capsules. Differences in leachate quality were not as dramatic as anticipated, probably because the efficiency of the leachate recirculation system at distributing leachate throughout the waste body in the recirculation cell was low.     

Phosphorus budgets and riverine phosphorus export in northwestern Ohio watersheds

Phosphorus (P) budgets for large watersheds are often used to predict trends in riverine P export. To test such predictions, we calculated annual P budgets for 1975-1995 for soils of the Maumee and Sandusky watersheds of northwestern Ohio and compared them with riverine P export from these watersheds. Phosphorus inputs to the soils include fertilizers, manure, rainfall, and sludge while outputs include crop removal and nonpoint-source export via rivers. Annual P inputs decreased due to reductions in fertilizer and manure inputs. Annual outputs increased due to increasing crop yields. Net P accumulation decreased from peak values of 13.4 and 9.5 kg P ha(-1) yr(-1) to 3.7 and 2.6 kg P ha(-1) yr(-1) for the Maumee and Sandusky watersheds, respectively. Thus, P budget analysis suggests that riverine P export should have increased throughout the study period, with smaller increases during more recent years. However, detailed water quality studies show that riverine export of total phosphorus (TP) has decreased by 25 to 40% and soluble reactive phosphorus (SRP) by 60 to 89%, both due primarily to decreases from nonpoint sources. We suggest that these decreases are associated with farmers' adoption of practices that minimize transport of recently applied P fertilizer and of sediments via surface runoff, coupled with changes in winter weather conditions. In comparison with most Midwestern watersheds, rivers draining these watersheds have high unit area yields of TP, low unit area yields of SRP, and high ratios of nonpoint source- to point source-derived P.     

Differences between weekday and weekend air pollutant levels in southern California

Ambient air quality data were analyzed to empirically evaluate the effects of reductions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) emissions on weekday and weekend levels of ozone (O3; 1991-1998) and particulate NO3- (1980-1999) in southern California. Despite significantly lower O3 precursor levels on weekends, 20 of 28 South Coast Air Basin (SoCAB) sites (28 of all 78 southern California sites) showed statistically significant higher mean O3 levels on Sundays than on weekdays (p < 0.01); 49 of the remaining 50 sites showed no significant differences between mean weekday and Sunday peak O3 levels. We also observed no statistically significant differences between mean weekday and weekend concentrations of particulate NO3- or nitric acid (HNO3, the precursor of particulate NO3-). Averaged over sites, the mean Sunday NOx and nonmethane hydrocarbon concentrations were 25-41% and 16-30% lower, respectively, than on weekdays. Site-to-site differences between weekend and weekday mean peak hourly O3 levels were related to whether O3 formation was limited by the availability of NOx. A thermodynamic equilibrium model predicts that particulate NO3- levels would decrease in response to a reduction of HNO3, and that particulate ammonium NO3- formation was not limited by the availability of ammonia. The similarity of mean weekday and weekend levels of NO3- therefore did not result from limitations on the formation of particulate NO3- from its precursor, HNO3.     

Specific Conductance and pH as Indicators of Watershed Disturbance in Streams of the New Jersey Pinelands, USA

/ We used linear regression to independently and jointly relate specific conductance and pH measured at New Jersey Pinelands stream sites to the percentage of altered land in a watershed. Percentage altered land included developed and agricultural land uses and represented watershed disturbance for a given site. Median values calculated for a 2-year period (September 1992 through August 1994) characterized pH and specific conductance at the study sites. We found the relationships between the median values for both water-quality measures and percentage altered land for a site to be consistent across subregion and dominant altered-land use. Our results also demonstrated that the water-quality/altered-land relationships developed using median values were similar to relationships developed using data from any single-sample period within the entire study period. Individually, pH and specific conductance explained 48% and 56%, respectively, of the variability in watershed disturbance among study sites. The joint use of pH and specific conductance explained 79% of the watershed disturbance variability among sites. The joint use of these easily obtained water-quality measures can provide a quick assessment of instream water-quality impacts from upstream watershed disturbance at any Pinelands stream site. Additionally, a range in pH and specific conductance, and hence a range in ambient water quality, can be predicted for a given altered-land percentage or a change in existing altered-land conditions.     

LAND SUBSIDENCE: AN ECONOMIC ANALYSIS1

ABSTRACT. Land subsidence due to groundwater overdraft has been assumed to be one of Arizona's major water related problems. This paper investigates the premise from an economic point of view and concludes that in the case of Arizona the physical fact of land subsidence has little or no economic significance.     

Efficiency of energy delivery systems: I. An economic and energy analysis

Energy-return-on-investment (ERI) analysis is a variation of more traditional cost-benefit analyses, a variation that is particularly important in times of diminishing fuel resources. We present a simple set of procedures for ERI analysis and apply those procedures to central New York State, where there is a proposal for a new 870 MW_e coal-fired generating station. We compared the energy and dollar costs of building that facility with the costs of an alternative comprehensive regional program of insulation. The analysis showed that regional insulation was more efficient in conserving energy than the plant was in providing it by at least a factor of 4 in economic terms and by a factor of more than 15 when viewed as energy returned on energy invested.     

A TREE-RING RECONSTRUCTION OF DROUGHT IN SOUTHERN CALIFORNIA1

ABSTRACT: Indices of annual diameter growth of trees were used to reconstruct drought in southern California back to A.D. 1700. A regional Palmer Drought Index served as predictand and tree-ring indices from eight sites as predictors in multiple linear regression analyses that yielded the prediction (reconstruction) equations. The regression explained 69 percent of the variance in Palmer Index in the period of calibration. The long-term reconstruction indicated that drought was rare in the first half of the current century relative to other discrete 50-year periods, and that based on evidence to date the last half of the 20th century may well turn out to be the most drought prone since A.D. 1700 in southern California.     

GAGE DENSITY AND LOCATION FOR ESTIMATING MEAN ANNUAL PRECIPITATION IN MOUNTAINOUS AREAS1

ABSTRACT: Data from a network of 45 shielded precipitation gages on the Reynolds Creek Experimental Watershed in Southwestern Idaho were analyzed to determine the optimum gage density for estimating mean annual precipitation. Four subsets of the 45 gage network were used to derive a curve of mean annual precipitation versus number of gages with a confidence band at the 95 percent level. When less than 20 gages were used in the estimate, the confidence interval widens rapidly. Estimates were improved by stratifying gages on the basis of plant cover class or by elevation bands. Sixty-four percent of the variation in mean annual precipitation was accounted for by elevation and cover class. The aspect and hydrologic soil classification were not statistically significant.     

RESULTS OF ACIDIZING WATER WELLS IN ARIZONA1

Two wellfields have been developed to provide water for a coal fired electric generating station in Arizona. Wellfield No. 1 penetrates the unconfined Coconino Sandstone aquifer, and wellfield No. 2 penetrates the composite Kaibab Limestone-Coconino Sandstone aquifer where ground water occurs under confined conditions. A well in each wellfield was pumped and water level drawdown data were collected before and after acidizing. The drawdown data at the various pumping rates were analyzed to determine the potential benefits of acidizing production water wells in both wellfields. After acidizing, the specific capacity of the well in wellfield No. 1 was improved about 50 percent at water production rates ranging from about 200 to 500 gallons per minute (gpm) (13 to 32 liters per second (lps)). After acidizing, the specific capacity of the well completed in wellfield No. 2 was improved about 100 percent at pumping rates ranging from about 1,250 to 2,200 gpm (79 to 139 lps). An annual saving of approximately 11 percent in pumping costs can be realized in wellfield No. 2, and savings are approximately four percent in wellfield No. 1. Acidization is beneficial for wells that can produce more than 500 gpm (32 lps), and is of marginal value for those that produce less than that amount.