1,720,973 research outputs found
Direct carbon dioxide emissions from civil aircraft
No full textGlobal airlines consume over 5 million barrels of oil per day, and the resulting carbon dioxide (CO2) emitted by aircraft engines is of concern. This article provides a contemporary review of the literature associated with the measures available to the civil aviation industry for mitigating CO2 emissions from aircraft. The measures are addressed under two categories – policy and legal-related measures, and technological and operational measures. Results of the review are used to develop several insights into the challenges faced.The analysis shows that forecasts for strong growth in air-traffic will result in civil aviation becoming an increasingly significant contributor to anthropogenic CO2 emissions. Some mitigation-measures can be left to market-forces as the key-driver for implementation because they directly reduce airlines' fuel consumption, and their impact on reducing fuel-costs will be welcomed by the industry. Other mitigation-measures cannot be left to market-forces. Speed of implementation and stringency of these measures will not be satisfactorily resolved unattended, and the current global regulatory-framework does not provide the necessary strength of stewardship. A global regulator with ‘teeth’ needs to be established, but investing such a body with the appropriate level of authority requires securing an international agreement which history would suggest is going to be very difficult.If all mitigation-measures are successfully implemented, it is still likely that traffic growth-rates will continue to out-pace emissions reduction-rates. Therefore, to achieve an overall reduction in CO2 emissions, behaviour change will be necessary to reduce demand for air-travel. However, reducing demand will be strongly resisted by all stakeholders in the industry; and the ticket price-increases necessary to induce the required reduction in traffic growth-rates place a monetary-value on CO2 emissions of approximately 7–100 times greater than other common valuations. It is clear that, whilst aviation must remain one piece of the transport-jigsaw, environmentally a global regulator with ‘teeth’ is urgently required
Assessing the feasibility and benefits of a shared-fleet collaboration in urban logistics: a case study of a public-private partnership in the UK
No full text1. Purpose: shared-fleet operations, where the collection/delivery (CD) rounds of one fleet (the ‘donor’ fleet) are optimised to include the CD activity of another, are a possible approach to reducing freight vehicle impacts in urban centres. The aims of this study were to: (i) determine the feasibility of a shared-fleet collaboration involving a private company (Carnival UK, (CUK)) and a public municipal authority (Southampton City Council, (SCC)) as the prospective fleet donor; ii) quantify, based on real-world data, the potential benefits of such a shared-fleet collaboration in terms of reducing vkm and emissions of carbon dioxide (CO2); (iii) assess the potential for a real-world trial to identify operational challenges and practicalities.2. Research approach: a one-week survey of business-as-usual (BAU) deliveries made by local suppliers to CUK’s warehouse was undertaken to quantify consignment volumes, weights and receipt times. These data, together with SCC’s current courier fleet schedules, were used to quantify the feasibility and benefits of merging operations. Route optimisation tools were employed to model an intervention scenario where SCC vehicles incorporated collections of CUK’s consignments from local suppliers into their existing CD rounds. The intervention was compared to BAU toquantify the potential reductions in vkm and CO2 emissions, with suitable suppliers identified for a possible real-world trial.3. Findings and originality: a shared-fleet collaboration involving 20 local suppliers serviced by five SCC vans performing 19 rounds/week could achieve reductions of: 80% in vehicles used; 56% in warehouse visits; 32% in vkm; and 89% in CO2 emissions. A real-world trial is being planned to understand practical and real-world scheduling challenges.4. Research impact: the research challenge lies in optimising for both fixed and more dynamic demands across both the donor and secondary fleets where some activities take priority and where vehicle capacity is fixed. A Travelling Salesman optimisation approach considering time windows and the range constraints of electric vehicles was used along with a time-based cost allocation method to share costs and benefits fairly between the parties.5. Practical impact: the research identified a practical approach for public authorities to enhance the efficiency of their vehicles by collaboratively sharing them, while also generating additional revenue for the authority through providing a logistics service. It also highlights the issues associated with establishing and managing such a collaboration where the donor fleet has to cope with fixed and dynamic demands. A real-world trial emanating from the findings is planned for later in 2023/24
Including congestion effects in urban road traffic CO2 emissions modelling: do local government authorities have the right options?
No full textTailpipe emissions from vehicles on urban road networks have damaging impacts, with the problem exacerbated by the common occurrence of congestion. This article focuses on carbon dioxide because it is the largest constituent of road traffic greenhouse gas emissions. Local Government Authorities (LGAs) are typically responsible for facilitating mitigation of these emissions, and critical to this task is the ability to assess the impact of transport interventions on road traffic emissions for a whole network.This article presents a contemporary review of literature concerning road traffic data and its use by LGAs in emissions models (EMs). Emphasis on the practicalities of using data readily available to LGAs to estimate network level emissions and inform effective policy is a relatively new research area, and this article summarises achievements so far. Results of the literature review indicate that readily available data are aggregated at traffic level rather than disaggregated at individual vehicle level. Hence, a hypothesis is put forward that optimal EM complexity is one using traffic variables as inputs, allowing LGAs to capture the influence of congestion whilst avoiding the complexity of detailed EMs that estimate emissions at vehicle level.Existing methodologies for estimating network emissions based on traffic variables typically have limitations. Conclusions are that LGAs do not necessarily have the right options, and that more research in this domain is required, both to quantify accuracy and to further develop EMs that explicitly include congestion, whilst remaining within LGA resource constraints
Optimising the logistics of urban healthcare through a shared-fleet collaboration
No full textPurpose: shared-fleet operations, where the collection/delivery (CD) rounds of one fleet (the ‘donor’ fleet) are optimised to include the CD activity of another, are one approach to reducing freight vehicle impacts in urban centres. This research investigates the potential benefits of shared-fleet logistics in a healthcare setting (reduced costs, vehicle-kilometres (vkm), and CO2 emissions), specifically between Southampton City Council (SCC, as the ‘donor’ fleet) and the NHS, with SCC’s electric courier vans (n=9) collecting pathology samples from local GP surgeries (n=78) across Southampton in addition to their existing CD activities.Research Approach: this study used historic data provided by the NHS on pathology sample generation rates from the 78 GP surgeries around Southampton, along with the daily rounds of SCC’s electric courier vans to model the impacts of shared-fleet collection in comparison to the business-as-usual (BAU) scenario where a 3rd party fleet is used by the NHS. Proprietary optimisation software was used to devise shared rounds incorporating constraints such as time windows, electric van payload capacity and range. The research is also exploring how the various costs and benefits can be equitably allocated and shared between the parties.Findings and OriginalityResults indicated that implementing an electric shared-fleet operation where 9 existing local authority fleet vehicles served 78 GP surgeries as part of their existing round activity, collecting an average of ~40 samples per day per surgery, would provide annual reductions of 1,518 vehicles routes (40%), 13,156 vkm (3%), and 59.961 tonnes of CO2 emissions (69%) compared to the BAU situation. Also, this could potentially reduce overall costs for the NHS by £42,504 (14%) annually.Research Impact: the research challenge entails optimising both fixed and dynamic demands across the donor fleet in a shared-fleet operation whilst accounting for prioritised activities and fixed vehicle capacity. A Travelling Salesman optimisation approach was employed to address this challenge, incorporating time windows and a range of constraints impacting on electric vehicles. A time-based cost allocation method was utilised to equitably distribute costs and benefits between the collaborating parties.Practical Impact: the research has identified a practical approach for public authorities to enhance the efficiency of their vehicles by collaboratively sharing available capacity whilst generating additional revenue. The study has also demonstrated how the NHS can reduce their transport footprint by using shared-fleet collaborations to help reach their zero emissions target by 2040. It also highlights the issues associated with establishing and managing such a collaboration where the donor fleet must cope with fixed and dynamic demands.<br/
Local government authority attitudes to road traffic CO<sub>2</sub> emissions modelling: a British case study
No full textLocal government authorities (LGAs) play a key role in facilitating mitigation of road traffic CO2 emissions and must engage in emissions modelling to quantify the impact of transport interventions. Existing Emissions Model (EM) methodologies range from aggregate to disaggregate approaches, with more detail normally entailing more resources. However, it is not clear which approaches LGAs actually utilise. This article reports results of a survey designed to discover the level of detail considered practical by British LGAs (n = 34). Results show that resource scarcity is important, with particular importance attached to EM reusability and convenient input data sources. Most LGA EMs use traffic variable inputs (predominantly traffic flow and traffic average speed), with this approach being the best-fit for LGA resources. Link-by-link sources of data rated highly for convenience are road traffic models and urban traffic control systems
Evaluating the feasibility of a shared-fleet operation in healthcare logistics between public organisations
No full textUrban logistics suffer from unique challenges due to the increasing demands of e-commerce, rising customer expectations, and the absence of centralised coordination. Shared-fleet logistics, a collaborative approach that combines loads and vehicle capacity to improve vehicle utilisation, has been proposed as a solution to address these challenges. This study aims to quantify the potential environmental and economic benefits of implementing a shared-fleet operation involving two public sector organisations. The research focuses on a specific case study using a historical dataset of vehicle movements, wherein a local authority's fleet of electric courier vehicles is shared with the National Health Service (NHS) for transporting pathology samples from 78 surgeries to the laboratory for analysis, thereby replacing the reliance on a third-party logistics provider. The benefits suggested by the results included a 17% reduction in costs, a 3% decrease in overall vehicle kilometres travelled, a 69% decrease in carbon dioxide (CO2) emissions, a 40% reduction in vehicle numbers, and a 27% reduction in total duty time. These results emphasise the considerable potential of shared-fleet operations to alleviate both environmental and economic problems in urban logistics, encouraging public sector organisations to actively pursue the implementation of collaborative solutions to enhance the efficiency of their own-account vehicles while making positive contributions to environmental sustainability
Locating urban freight micro-consolidation centres: a practical methodology
No full textMicro-consolidation centres (MCCs) can offer sustainable freight logistics solutions in urban areas. This paper presents a novel methodology for Local Government Authorities (LGAs) to promote the future development and use of MCCs by freight logistics companies through identifying suitable sites for such facilities in urban areas within their districts. The methodology is practical for LGAs to use within the constraints of limited financial and human resources, and is based on a distillation of previous research, showing how a simple, structured methodology can work with imperfect real-world data. The methodology was trialled in practice in Portsmouth, UK, where two preferred MCC sites were successfully identified for progressing to real-world trials. The methodology was designed to be transferrable, and the case study application to Portsmouth identified insights into the challenges affecting its utility in other urban areas, such as maintaining equity between stakeholders and engaging personnel whose time resources are scarce
Enabling safe and sustainable medical deliveries by connected autonomous freight vehicles operating within dangerous goods regulations
No full textHealth service providers in developed nations are responsible for 5% of their national carbon emissions, much of which originate from transport and supply chains. Connected autonomous freight vehicles (CAV-Fs) offer the potential to reduce this impact and enable lower cost operations, with trials being explored across the world. Transportation and carriage regulations, particularly in relation to the movement of dangerous goods (DG) such as medicines and diagnostic specimens, have not been developed for and applied to this new transport mode, particularly where loads are unaccompanied. Through an audit of current legislation and practice, this paper evaluates current DGs regulations applied to the transportation of medical products and medicines by autonomous road vehicles. Where existing regulations are not appropriate for CAV-Fs, recommendations and adaptations have been proposed to support safe and practical application. Remote monitoring and tracking of vehicles are critical for ensuring load security, quick and effective incident response, and management of documents and communications between parties. Loading/unloading procedures are significantly more important than in crewed vehicles, with load segregation and recording of all activity being of key importance. Other recommendations relate to training provision, vehicle specifications, and product health monitoring
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