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641.
The U.K. government is committed to establishing a coherent network of marine protected areas by 2012 and the recent Marine and Coastal Access Act, 2009 will designate marine conservation zones and provide wider access rights to the coast. To fulfill these goals, this article argues the need for a clearer, shared understanding of the social value of protected areas in creating new designations and managing existing ones. Although marine and coastal environments attract many people and are vitally important in terms of realized and potential social value, the majority of the public in the United Kingdom lacks understanding and awareness regarding them. Combined with this, the social value of marine and coastal protected areas (MCPAs) have been largely ignored relative to conservation and economics, with the latter invariably taking precedence in environmental policymaking. Social value reflects the complex, individual responses that people experience in a given place. Many reasons determine why one area is valued above another, and this research investigates the social value of MCPAs from a practitioner's perspective through a series of interviews. Understanding why we “socially” value MCPAs will ultimately equip managers with an informed understanding of these spaces, influence management decisions, and, potentially, policymaking. This article defines social value in the context of MCPAs in England and Wales from a practitioner perspective, explores key concepts, and suggests possible improvements in decision-making. 相似文献
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643.
研究目的:针对此次大地震中我国西南地区铁路网暴露出的问题和不足,对铁路网规划进行了再思考,并提出了一些相关的建议.研究结论:通过分析铁路在抗震救灾中发挥的重要作用和此次大地震中暴露出我国西南地区铁路网存在的问题和不足,对铁路网规划提出了一些相关方面的建议:要与经济发展相协调、与灾害应急保障系统的要求相结合综合考虑铁路网规划;通过建设和加强对外通道、扩大内部路网规模、建设资源开发型铁路、完善快速客货运输网络等措施不断完善通道建设和提高路网的灵活性;统筹考虑各种交通运输方式之间的协调衔接,充分发挥综合交通系统优势等. 相似文献
644.
论中国公路网规划环境影响评价主要目标与内容 总被引:1,自引:0,他引:1
根据《中华人民共和国公路法》和《中华人民共和国环境影响评价法》相关内容的解读,从环评的角度论述了公路网规划的特点,总结了应在公路网规划阶段控制的生态环境问题。在此基础上,文中从决策支持、规划完善和预防措施3个方面全面阐述了公路网规划环评的主要目标,以上述目标为导向提出了中国当前开展公路网规划环评的指导思想与工作原则,并全面介绍了为实现上述目标,公路网规划环评所应包含的主要内容。 相似文献
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This paper presents a long-term investment planning model that co-optimizes infrastructure investments and operations across transportation and electric infrastructure systems for meeting the energy and transportation needs in the United States. The developed passenger transportation model is integrated within the modeling framework of a National Long-term Energy and Transportation Planning (NETPLAN) software, and the model is applied to investigate the impact of high-speed rail (HSR) investments on interstate passenger transportation portfolio, fuel and electricity consumption, and 40-year cost and carbon dioxide (CO2) emissions. The results show that there are feasible scenarios under which significant HSR penetration can be achieved, leading to reasonable decrease in national long-term CO2 emissions and costs. At higher HSR penetration of approximately 30% relative to no HSR in the portfolio promises a 40-year cost savings of up to $0.63 T, gasoline and jet fuel consumption reduction of up to 34% for interstate passenger trips, CO2 emissions reduction by about 0.8 billion short tons, and increased resilience against petroleum price shocks. Additionally, sensitivity studies with respect to light-duty vehicle mode share reveal that in order to realize such long-term cost and emission benefits, a change in the passenger mode choice is essential to ensure higher ridership for HSR. 相似文献
647.
为解决无人驾驶路径规划过程中的决策控制问题,文章针对深度确定性策略梯度算法在未知环境中随着搜索空间的增大,出现训练效率低、收敛不稳定等缺点,提出了基于奖励指导的改进算法。首先在每回合内采用基于奖励的优先级经验回放,减少深度确定性策略梯度算法随机探索的盲目性,提高智能车学习效率。然后在回合间基于奖励筛选优秀轨迹,便于指导智能车对复杂空间的探索,得到稳定的控制策略。最后,在开源智能驾驶仿真环境进行仿真。实验结果表明改进后的深度确定性策略梯度算法性能优于原来的算法,训练效率和收敛稳定性均得到有效提升。 相似文献
648.
Exposure to fine particulate matter from vehicle exhaust is associated with increased health risk. This study develops a new approach for creating spatially detailed regional maps of fine particulate matter concentration from vehicle exhaust using a dispersion model to better evaluate these risks. The spatial extent, diurnal, and seasonal patterns of concentration fields across Los Angeles County, California are evaluated and population exposure and exposure equity by race and income are investigated. The results demonstrate how this modeling approach can create new knowledge about vehicle emissions exposure. This approach also provides a method for proactively screening out regional plans, or specific projects within these plans, that are likely to cause air quality concerns. A proactive and regional air quality assessment can identify potential problems earlier in the planning process and a wider range of solutions, saving time, money and protecting public health. The detailed concentration maps can also be used to improve the siting of regulatory air quality monitors and provide more accurate exposure data for epidemiology studies. 相似文献
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650.
Ride-hailing is a clear initial market for autonomous electric vehicles (AEVs) because it features high vehicle utilization levels and strong incentive to cut down labor costs. An extensive and reliable network of recharging infrastructure is the prerequisite to launch a lucrative AEV ride-hailing fleet. Hence, it is necessary to estimate the charging infrastructure demands for an AEV fleet in advance. This study proposes a charging system planning framework for a shared-use AEV fleet providing ride-hailing services in urban area. We first adopt an agent-based simulation model, called BEAM, to describe the complex behaviors of both passengers and transportation systems in urban cities. BEAM simulates the driving, parking and charging behaviors of the AEV fleet with range constraints and identifies times and locations of their charging demands. Then, based on BEAM simulation outputs, we adopt a hybrid algorithm to site and size charging stations to satisfy the charging demands subject to quality of service requirements. Based on the proposed framework, we estimate the charging infrastructure demands and calculate the corresponding economics and carbon emission impacts of electrifying a ride-hailing AEV fleet in the San Francisco Bay Area. We also investigate the impacts of various AEV and charging system parameters, e.g., fleet size, vehicle battery capacity and rated power of chargers, on the ride-hailing system’s overall costs. 相似文献