Landfill diversion in a decentralized setting: A dynamic assessment of landfill taxes

We analyze the process of landfill diversion and its main determinants, by embedding the dynamics in a frame where economic, geographical and policy variables come into play. In addition to structural and economic drivers, we primarily investigate whether the Italian tax has been effective in supporting landfill diversion. Although the Italian landfill tax dates back to 1996, the oldest in the EU, its effectiveness in terms of landfill diversion has not been assessed yet. The complexity primarily derives from the decentralized regional implementation and the absence of a full coherent dataset covering all regions. We merge this new and original data on taxes to an integrated dataset which includes economic, waste and policy variables at regional level over the period 1999–2008. Panel regressions show that the effect of tax is significant, even when taking into account for its possible endogeneity. Regions that have increased such taxes have improved waste disposal performances over time. Landfill taxes are surely not the only instrument policy makers might introduce, but they seem to play a relevant role in the evolution of Italian waste disposal performances.     

Renewable energy,non-renewable energy and sustainable development

The purpose of the present study is to analyse the effects of renewable energy and non-renewable energy on sustainable development. This study is pioneering in this respect because it analyses the effect of renewable energy on adjusted net savings, which is a good sustainable development variable. For this purpose, the data of 40 developed and 73 developing countries were included. According to the estimation results obtained in the study, renewable energy has a positive and statistically significant effect on sustainable development both in developed countries and in developing countries. The impact of renewable energy on sustainable development is greater than the impact of non-renewable energy. In this respect, as the renewable energy amount increases, the level of sustainable development increases. According to these results, the fact that countries use renewable energy more than non-renewable energy sources is extremely important in terms of making progress towards sustainability of development and the 2030 Sustainable Development Goals.     

Manure and adoption of modern seeds in cereal‐based systems in West African drylands: linkages and (non)complementarities

Using a stepwise approach that combines several econometric methods, we assessed whether or not the adoption of modern seeds and the use of manure in cereal‐based systems are linked and, if so, what are the driving forces of the linkages between these two agricultural technologies under dry‐climate conditions in West Africa. We found complementary and substitutability linkages arising from jointness and endogeneity between the two technologies. Specifically, our findings reveal positive joint determination along with negative endogeneity between the two technologies indicating that, controlling for observable variables, both technologies are positively linked, but unobserved factors that affect one adoption decision are negatively correlated with the other. After controlling for jointness and endogeneity, we found significant complementarity linkages showing a significant positive effect of manure use on the adoption of modern seeds, which is also significantly and positively affected by the number of cash crops grown and remittances. The two technologies are reversely affected by schooling and the incidence of soil fertility problems within the farm, whereas the amount of healthy land has a positive effect on both. The study suggests that organic fertilizer can serve as an enabling factor for greater adoption of modern seeds, especially in less favourable climate areas, and strongly supports the argument behind the need to breed seeds suitable for the use of organic fertilizers. These findings provide avenues for re‐orientation of policies that promote the use of modern seeds in dryland areas in sub‐Saharan Africa, with a possibility of breeding and promoting them in packages with organic fertilizers to upscale their adoption.     

The effects of pricing waste generation: A synthetic control approach

To internalize pollution externalities into household waste generation, Unit Pricing Systems (UPS) have been adopted worldwide. This paper evaluates the causal effects of a UPS on the disposal of municipal solid waste in Trento, Italy. Using a unique panel dataset of monthly waste generation in Italian municipalities, we employ the synthetic control method, which allows us to account for possible time-varying effects of unobservables. Our results show that the policy was effective, with a significant decrease of the priced waste stream, unsorted waste, by 37.5%. This effect seems to be largely driven by behavioral changes towards waste avoidance (−8.6%) and possibly by a smaller increase in recycling (+6.1%). By comparing these results to those obtained by a difference-in-differences approach, we show that failing to account for time-varying effects of unobservables may lead to a mismeasurement of policy effects.     

Secondary collisions and injury severity: A joint analysis using structural equation models

Objective: This study aims to investigate the contributing factors to secondary collisions and the effects of secondary collisions on injury severity levels. Manhattan, which is the most densely populated urban area of New York City, is used as a case study. In Manhattan, about 7.5% of crash events become involved with secondary collisions and as high as 9.3% of those secondary collisions lead to incapacitating and fatal injuries.

Methods: Structural equation models (SEMs) are proposed to jointly model the presence of secondary collisions and injury severity levels and adjust for the endogeneity effects. The structural relationship among secondary collisions, injury severity, and contributing factors such as speeding, alcohol, fatigue, brake defects, limited view, and rain are fully explored using SEMs. In addition, to assess the temporal effects, we use time as a moderator in the proposed SEM framework.

Results: Due to its better performance compared with other models, the SEM with no constraint is used to investigate the contributing factors to secondary collisions. Thirteen explanatory variables are found to contribute to the presence of secondary collisions, including alcohol, drugs, inattention, inexperience, sleep, control disregarded, speeding, fatigue, defective brakes, pedestrian involved, defective pavement, limited view, and rain. Regarding the temporal effects, results indicate that it is more likely to sustain secondary collisions and severe injuries at night.

Conclusions: This study fully investigates the contributing factors to secondary collisions and estimates the safety effects of secondary collisions after adjusting for the endogeneity effects and shows the advantage of using SEMs in exploring the structural relationship between risk factors and safety indicators. Understanding the causes and impacts of secondary collisions can help transportation agencies and automobile manufacturers develop effective injury prevention countermeasures.     

经济、环境与人口健康的相互影响:基于我国省区面板数据的实证分析

经济增长造成环境变化;收入水平和环境质量共同影响着人口健康;人口健康状况又影响着经济增长.本文构建了一个描述兰者之间关系的联立方程模型,使用省区面板数据.分析了我国20世纪90年代至今省区层面上经济、环境与人口健康的相互影响.实证结果表明,工业污染是经济增长的阻碍因素;经济增长对人口健康有显著的正影响,而工业污染对人口健康有显著的负影响;人口健康对经济增长的贡献不显著;教育状况对经济增长有显著促进作用,但对人口健康没有显著的直接影响;第三产业的发展有利于减少工业污染,改善环境质量.因此,发展教育事业和第三产业,是促进经济增长和提高环境质量的有效举措.