Graduated driver licensing restrictions: awareness, compliance, and enforcement in North Carolina

PROBLEM: This study examined the extent to which critical restrictions in North Carolina's graduated driver licensing (GDL) system are known, adhered to, and enforced. METHOD: Teenagers and their parents were recruited as they applied for either an intermediate or full license at 1 of 23 licensing offices. Telephone interviews were conducted with 900 teenagers and their parents. RESULTS: Awareness of North Carolina's night and passenger restrictions was very high among both parents and teenagers. Ten percent of teenagers reported violating the night restriction without their parents' knowledge, and 15% had done so with their parents' approval. Only 4% of parents reported allowing their teenagers to drive with more than one teenage passenger, but 19% of teenagers reported that they were allowed to do this. Violations of the passenger restriction without parental knowledge were more common than violations of the night restriction (22% vs. 10%, respectively). Among teenagers who violated restrictions without their parents' knowledge, most reported doing so only once or a few times. Teenagers expressed little concern about detection, although a majority reported driving more carefully to avoid police notice. Neither parents nor teenagers knew much about police enforcement of GDL restrictions. To obtain a sense of the views of law enforcement officers, informal interviews were conducted with 20 officers from five diverse communities and the state highway patrol. These officers were highly supportive of GDL but unfamiliar with many of the specific provisions. Moreover, enforcement of GDL restrictions did not appear to be a high priority. IMPACT ON INDUSTRY: There is a need to increase the belief among teens (and parents) that police are enforcing GDL restrictions in their community; law enforcement participation in well-publicized traffic safety enforcement efforts would likely produce this result.     

Alcohol ignition interlock programs

The alcohol ignition interlock is an in-vehicle DWI control device that prevents a car from starting until the operator provides a breath alcohol concentration (BAC) test below a set level, usually .02% (20 mg/dl) to .04% (40 mg/dl). The first interlock program was begun as a pilot test in California 18 years ago; today all but a few US states, and Canadian provinces have interlock enabling legislation. Sweden has recently implemented a nationwide interlock program. Other nations of the European Union and as well as several Australian states are testing it on a small scale or through pilot research. This article describes the interlock device and reviews the development and current status of interlock programs including their public safety benefit and the public practice impediments to more widespread adoption of these DWI control devices. Included in this review are (1) a discussion of the technological breakthroughs and certification standards that gave rise to the design features of equipment that is in widespread use today; (2) a commentary on the growing level of adoption of interlocks by governments despite the judicial and legislative practices that prevent more widespread use of them; (3) a brief overview of the extant literature documenting a high degree of interlock efficacy while installed, and the rapid loss of their preventative effect on repeat DWI once they are removed from the vehicles; (4) a discussion of the representativeness of subjects in the current research studies; (5) a discussion of research innovations, including motivational intervention efforts that may extend the controlling effect of the interlock, and data mining research that has uncovered ways to use the stored interlock data record of BAC tests in order to predict high risk drivers; and (6) a discussion of communication barriers and conceptual rigidities that may be preventing the alcohol ignition interlock from taking a more prominent role in the arsenal of tools used to control DWI. Whether interlock programs can help public policymakers achieve their expressed goals of substantially reducing the level of impaired driving will remain uncertain until procedural barriers and intransigent judiciary practices can be overcome that provide for more systematic routine use of interlock programs. Despite strong effectiveness evidence in all studies to date, the real potential of this technology to reduce the road toll cannot be estimated until they are more widely adopted.     

Association between older driver characteristics, on-road driving test performance, and crash liability

From May 1999, a new system for licensing older drivers was introduced in New Zealand. It included a practical on-road driving test with expanded scope, to be completed every two years from the time the driver turns 80. The relationship between crashes and test performance needed to be studied to inform the debate regarding the testing system. The population studied was all drivers who entered this licensing system during its first three years of operation. They were defined as crash involved if they were involved in an injury crash during the two years following their first licensure under the new system. Logistic regression was used to describe the risk of crash involvement in terms of driving test performance and other driver characteristics. Each driving test failure was associated with a 33% increase in the odds of crash involvement (95% CI 14% to 55%), controlling for age, gender, minor traffic violations, and whether the older driver lived with another licensed driver or not. Minor traffic violations in the two years following the driving test were associated with twice the odds of crash involvement. These results suggest that the new on-road driving test does identify older driver behaviors or limitations that are related to crash liability. It is anticipated that the results presented here will provide essential information for discussing older driver licensing systems, whose impact will grow in importance as the population of drivers ages.     

Mitigating nutrient leaching with a sub-surface drainage layer of granulated tires

Markets for scrap tires have expanded since the early 1990s with the development of value-added applications such as tire-derived fuel and crumb-rubber-amended asphalt. Granulated tires have also displayed the ability to adsorb volatile organic compounds, indicating that the rubber material can be a useful filter media. Sand-based root zones, typically used for golf course putting green and athletic field construction, lack sufficient cation exchange capacity to restrict nitrogen and phosphorus migration through the root zone and into sub-surface drainage systems. Therefore, the adsorptive properties of tire rubber for retaining nitrogen and phosphorus were studied when applied as a distinct sub-surface drainage or intermediate layer in golf course putting greens. A statistically significant reduction in the concentration of nitrate in leachate was achieved by replacing traditional pea gravel with equally sized granulated tires for the drainage layer media, although the mechanism of nitrate mitigation remains unclear. The results indicate that using granulated tires as a drainage layer or fill material beneath sand-based root zones does not compromise the function of the profile or quality of the vegetation while creating an environmentally beneficial and value-added option for scrap tire reuse.     

Field trial of a new aeration system for enhancing biodegradation in a biopile

The influence of a new aeration system on the biopile performance was investigated. The purpose was to increase biodegradation efficiency by optimising airflow through the pile. During a 1-month field trial, the performance of a new system using two perforated vertical pipes with wind-driven turbines was compared with that of a standard pile configuration with two horizontal perforated pipes. Both piles were composed of a similar mix of diesel-contaminated soils, woodchips, compost and NPK fertiliser. Hydrocarbons were recovered using solvent extraction, and determined both gravimetrically and by gas chromatography. Total heterotrophs, pH and moisture content were also assessed. Air pressure measurements were made to compare the efficiency of suction in the pipes. Results at the end of the experiment showed that there was no significant difference between the two piles in the total amount of hydrocarbon biodegradation. The normalised degradation rate was, however, considerably higher in the new system than in the standard one, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile. The pressure measurements showed a significant improvement in the suction produced by the new aeration system. However, many factors other than the airflow (oxygen supply) may influence and limit the biodegradation rates, including moisture content, age of contaminants and the climatic conditions. Additional experiments and modelling need to be carried out to explore further the new aeration method and to develop criteria and guidelines for engineering design of optimal aeration schemes in order to achieve maximum biodegradation in biopiles.     

Effect of cobalt sorption on metal fractionation in anaerobic granular sludge

A sequential extraction procedure was applied to two anaerobic methanogenic sludges (Eerbeek and Nedalco) to examine the speciation of micro- and macronutrients in the sludges after cobalt sorption by exposing the sludge to a 1 mM Co solution for 4 d at pH 7 and 30 degrees C. The effect of different physicochemical conditions on cobalt sorption was studied as well: effect of pH (6-8), effect of competition by a second trace element (Ni or Fe), modification of the granular matrix by glutaraldehyde or heat treatment, and EDTA (ethylenediaminetetraacetic acid) addition. Sorbed Co was found to distribute between the carbonates, organic matter + sulfides, and residual fractions. Cobalt adsorption resulted in an antagonistic interaction with other metals present in the granular matrix, evidenced by the solubilization of other trace elements (e.g., Ni, Cu, and Zn) as well as macronutrients (especially Ca and Fe). Modification of the sludge matrix by glutaraldehyde or heat treatment, or exposure to EDTA, led to serious modifications of the Co sorption capacity and strong interactions with multivalent cations (i.e., Ca(2+) and Fe(2+)).     

Source-separated municipal solid waste compost application to Swiss chard and basil

A growth room experiment was conducted to evaluate the bioavailability of Cu, Mn, Zn, Ca, Fe, K, Mg, P, S, As, B, Cd, Co, Cr, Hg, Mo, Na, Ni, Pb, and Se from a sandy loam soil amended with source-separated municipal solid waste (SSMSW) compost. Basil (Ocimum basilicum L.) and Swiss chard (Beta vulgaris L.) were amended with 0, 20, 40, and 60% SSMSW compost to soil (by volume) mixture. Soils and compost were sequentially extracted to fractionate Cu, Pb, and Zn into exchangeable (EXCH), iron- and manganese-oxide-bound (FeMnOX), organic-matter (OM), and structurally bound (SB) forms. Overall, in both species, the proportion of Cu, Pb, and Zn levels in different fractions followed the sequence: SB > OM > FeMnOX > EXCH for Cu; FeMnOX = SB > OM > EXCH for Pb; and FeMnOX > SB = EXCH > OM for Zn. Application of SSMSW compost increased soil pH and electrical conductivity (EC), and increased the concentration of Cu, Pb, and Zn in all fractions, but not EXCH Pb. Basil yields were greatest in the 20% treatment, but Swiss chard yields were greater in all compost-amended soils relative to the unamended soil. Basil plants in 20 or 40% compost treatments reached flowering earlier than plants from other treatments. Additions of SSMSW compost to soil altered basil essential oil, but basil oil was free of metals. The results from this study suggest that mature SSMSW compost with concentrations of Cu, Pb, Mo, and Zn of 311, 223, 17, and 767 mg/kg, respectively, could be used as a soil conditioner without phytotoxic effects on agricultural crops and without increasing the normal range of Cu, Pb, and Zn in crop tissue. However, the long-term effect of the accumulation of heavy metals in soils needs to be carefully considered.     

Ammonia emissions from swine houses in the southeastern United States

Ammonia (NH3) from confined animal feeding operations is emitted from several sources including lagoons, field applications, and houses. This paper presents studies that were conducted to evaluate NH3 emissions from swine finisher and sow animal houses in the southeastern USA. Management and climate variables including animal weight, feed consumption, housing gutter water temperature, total time fans operated per day, house air temperature, house ambient NH3 concentration, and animal numbers were measured to determine their individual and combined effect on NH3 emissions. Ammonia emissions varied on daily and seasonal bases with higher emissions during warmer periods. For finishers, the summertime housing emissions on a per-animal basis were 2.4 times higher than wintertime (7.0 vs. 3.3 g NH3 animal(-1) d(-1)) or 3.2 times higher when compared on an animal unit (AU) basis (1 AU = 500 kg) because of climate and animal size differences between measurement periods. For summertime, the emission factor for the finishing pigs was 7.8 times higher than for sows on an animal basis and 25.6 times higher on an AU basis. Simple models were developed for housing emissions based on (i) all measured factors that were independent of each other and (ii) on three commonly measured management factors. The two models explained 97 and 64%, respectively, of variations in emissions. Ammonia emissions were found to be somewhat less than other studies on the same type housing due to more representative housing concentration measurements and calibration of exhaust fans; thus, emission factors for these type houses will be less than previously thought.     

Dissolved phosphorus retention and release from a coastal plain in-stream wetland

Dissolved phosphorus (DP) can be released from wetlands as a result of flooding or shifts in water column concentrations. Our objectives were to determine the long-term (1460 d) DP retention and release characteristics of an in-stream wetland, and to evaluate how these characteristics respond to flooding, draining, and changes in DP concentrations. The studied in-stream wetland drains an agriculturally intensive subwatershed in the North Carolina Coastal Plain region. The wetland's DP retention and release characteristics were evaluated by measuring inflow and outflow DP concentrations, DP mass balance, and DP movement across the sediment-water column interface. Phosphorus sorption isotherms were measured to determine the sediment's equilibria P concentration (EPCo), and passive samplers were used to measure sediment pore water DP concentrations. Initially, the in-stream wetland was undersized (0.31 ha) and released 1.5 kg of DP. Increasing the in-stream wetland area to 0.67 ha by flooding resulted in more DP retention (28 kg) and low outflow DP concentrations. Draining the in-stream wetland from 0.67 to 0.33 ha caused the release of stored DP (12.1 kg). Shifts both in sediment pore water DP concentrations and sediment EPCo values corroborate the release of stored DP. Reflooding the wetland from 0.33 to 0.85 ha caused additional release of stored DP into the outflowing stream (10.9 kg). We conclude that for a time period, this in-stream wetland did provide DP retention. During other time periods, DP was released due to changes in wetland area, rainfall, and DP concentrations.     

Lead reduction and redistribution in the forest floor in New Hampshire northern hardwoods

Because of the affinity of organic matter for lead, atmospheric loadings of this pollutant have been strongly retained in the forest floor. With the regulation of Pb emissions, loadings have decreased. We measured changes in Pb in forest floor horizons at a variety of northern hardwood sites in New Hampshire from the late 1970s to the 1990s. In all seven of the sites in which horizons were distinguished within the forest floor, Pb was found to be declining in the upper (Oie) horizon, but not in the underlying Oa and A horizons. At the Hubbard Brook Experimental Forest (HBEF), this loss from the Oie resulted in a 36% loss of Pb from the forest floor as a whole between 1976 and 1997 (p < 0.001). In contrast, in six stands in the Bartlett Experimental Forest (BEF), losses of Pb averaging >50% from the Oi and Oe horizons (p = 0.01) between 1979 and 1994 were compensated by gains in the Oa and A horizons. Similarly, at seven additional stands in the White Mountain National Forest, changes in the forest floor as a whole from 1980 to 1995 were not statistically significant (redistribution within the forest floor was not evaluated at these sites). Lead concentrations were highest in the Oe or Oie in the 1970s, but were highest in the Oa horizon in the 1990s. There was no significant pattern of Pb loss or retention as a function of stand age across all the sites.