Objectives: We examined associations among race/ethnicity, socioeconomic factors, and driving status in a nationally representative sample of >26,000 U.S. high school seniors.
Methods: Weighted data from the 2012 and 2013 Monitoring the Future surveys were combined and analyzed. We imputed missing values using fully conditional specification multiple imputation methods. Multivariate logistic regression modeling was conducted to explore associations among race/ethnicity, socioeconomic factors, and driving status, while accounting for selected student behaviors and location. Lastly, odds ratios were converted to prevalence ratios.
Results: 23% of high school seniors did not drive during an average week; 14% of white students were nondrivers compared to 40% of black students. Multivariate analysis revealed that minority students were 1.8 to 2.5 times more likely to be nondrivers than their white counterparts, and students who had no earned income were 2.8 times more likely to be nondrivers than those earning an average of ≥$36 a week. Driving status also varied considerably by student academic performance, number of parents in the household, parental education, census region, and urbanicity.
Conclusions: Our findings suggest that resources—both financial and time—influence when or whether a teen will learn to drive. Many young people from minority or lower socioeconomic families who learn to drive may be doing so after their 18th birthday and therefore would not take advantage of the safety benefits provided by graduated driver licensing. Innovative approaches may be needed to improve safety for these young novice drivers. 相似文献
Worldwide, the amount of end-of-life vehicles (ELVs) reaches 50 million units per year. Once the ELV has been processed, it may then be shredded and sorted to recover valuable metals that are recycled in iron and steelmaking processes. The residual fraction, called automotive shredder residue (ASR), represents 25% of the ELV and is usually landfilled. In order to deal with the leachable fraction of ASR that poses a potential threat to the environment, a washing treatment before landfilling was applied. To assess the potential for full-scale application of washing treatment, tests were carried out in different conditions (L/S = 3 and 5 L/kgTS; t = 3 and 6 h). Moreover, to understand whether the grain size of waste could affect the washing efficiency, the treatment was applied to ground (<4 mm) and not-ground samples. The findings obtained revealed that, on average, washing treatment achieved removal rates of more than 60% for dissolved organic carbon (DOC), chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN). With regard to metals and chlorides, sulphates and fluoride leachable fraction, a removal efficiency of approximately 60% was obtained, as confirmed also by EC values. The comparison between the results for ground and not-ground samples did not highlight significant differences. 相似文献
Fuel consumption and collection costs of solid waste were evaluated by the aid of a simulation model for a given collection area of a medium-sized Italian city. Using the model it is possible to calculate time, collected waste and fuel consumption for a given waste collection route. Starting from the data for the current waste collection scenario with a Source Segregated (SS) intensity of 25%, all the main model error evaluated was ?1.2. SS intensity scenarios of 25%, 30%, 35% and 52% were simulated. Results showed an increase in the average fuel consumed by the collection vehicles that went from about 3.3 L/tonne for 25% SS intensity to about 3.8 L/tonne for a SS intensity of 52%. Direct collection costs, including crews and vehicle purchase, ranged from about 40 €/tonne to about 70 €/tonne, respectively, for 25% and 52% SS intensity. The increase in fuel consumption and collection costs depends on the density of the waste collected, on the collection vehicle compaction ratio and on the waste collection vehicle utilization factor (WCVUF). In particular a reduction of about 50% of the WCVUF can lead to an average increase of about 80% in fuel consumption and 100% in collection costs. 相似文献
Impact of urban air pollution has variety of focuses such as urban ecology, human health, economy, etc. But human health is
always given priority. Air pollution is threat to the lives of people living in big cities of Pakistan. In Lahore only there
die 1,250 people annually because of air pollution. A strong correlation exists between urban air pollution and human health
in Lahore. Growth of COPD is highest among other air pollution borne diseases. Existing mass transit system (one of driving
forces behind motor vehicular emission) in Lahore due to frequent stoppages, entering and exit in flow of traffic causes excess
discharge of motor vehicular carbon monoxide (CO) which is a hazardous to human health. Quantification and enumeration of
this discharge is essential for environmental management. The paper is an attempt to highlight human health effects of urban
air pollution through correlation and regression analysis. Further it is focused upon quantifying excess motor vehicular carbon
monoxide through application of simplified mobile emission model. In light of results emission control measures are recommended. 相似文献
Air pollution is threat to the lives of people living in big cities of Pakistan. In Lahore 1,250 people die annually because
of air pollution.Mass transit system that can be put forth as solution to urban air pollution is contingent with right choice
of system and its affiliation with motorized vehicles and nature of urban air pollution.Existing mass transit system in Lahore
due to untrue operation causes surfeit discharge of motor vehicular carbon monoxide. Tended relationships of mass transit
system with motorized vehicles and urban air pollution are quite noteworthy. The growing motor vehicles (a consequence of
flawed public mass transit system) are potential source of urban air pollution. This paper attempts to highlight correlations
and regression curves of existing mass transit system. Further it recommends a two facet approach for reduction of motor vehicular
air pollution in Lahore. 相似文献
We assess the performance of alternative rebate designs for plug-in electric vehicles. Based on an innovative vehicle choice model, we simulate the performance of rebate designs that vary in terms of vehicle technologies, consumer income eligibility, and caps on the price of vehicles eligible for subsidies. We compare these alternatives in terms of 1) the number of additional plug-in electric vehicles purchased, 2) cost-effectiveness per additional vehicle purchase induced, 3) total program cost, and 4) the distribution of rebate funding across consumer income classes. Using the status quo rebate policy in California as a reference case, we identify two alternative types of designs that are superior along all four performance criteria. 相似文献