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Traffic oscillation, a traffic phenomenon that generates many carbon emissions, originates from the amplification of traffic disturbance. The connected and automated vehicle (CAV) technology may help to weaken oscillations and reduce carbon emissions from mixed traffic. This paper explores the effects of various characteristics of disturbances and mixed platoons on CO 2 emissions under different disturbance types. The results indicate that the addition of even only one CAV reduces carbon emissions under some disturbances. The disturbance types that make mixed traffic increase carbon emissions have also been identified. Diverse disturbance characteristics play different essential roles in ecological impacts of CAVs. The platoon characteristics such as CAV's position in a platoon and the heterogeneity of human factors, affect the extent of carbon emission reduction. Based on these findings, this paper proposes optimization recommendations for CAV cooperative eco-driving and green traffic management. [ABSTRACT FROM AUTHOR]

Heavy-Duty Vehicles (HDVs) pose a significant challenge in meeting emissions reduction targets. However, studies on estimating emissions from Irish HDV fleet are rare. This paper estimates fuel consumption and CO 2 emissions from tractor-trailers that occupy nearly half of Ireland's HDV fleet using the European Commission recommended VECTO tool. To improve the estimation accuracy, driving cycles specific to Irish road conditions were developed utilising real naturalistic driving data from trucks. The Irish driving cycles significantly differ from the VECTO inbuilt driving cycles in percentage time spent in different gears, fuel consumption, and CO 2 emissions. CO 2 emissions estimated with Irish driving cycles range from 733 to 1961 g/km, while with VECTO driving cycles, the values ranged from 728 to 1865 g/km. Further, the study evaluated the sensitivity towards payload, road gradient, and idling percentages. The study insights would provide an essential evidence base for policymakers in Ireland. [Display omitted] • Developed Irish urban, regional, and freeway driving cycles. • Employed the VECTO tool to assess CO 2 emissions from Irish heavy-duty vehicle fleet. • Focused on tractor-trailers with a major share in the Irish fleet. • Evaluated the effect of idling, gradient, and payload on CO 2 emissions. • Fuel consumption is underestimated by up to 7.1% when the road gradient is ignored. [ABSTRACT FROM AUTHOR]

The goal of the Paris agreement (2015) is to achieve a climate-neutral world by mid-century. For maritime transport, the goal is a 50 % reduction of greenhouse gas emissions by 2050. This may be achieved using low and zero-emission fuels. LNG is a well-known low-carbon fuel for some ship types, but for application to medium to small-sized vessels, more cost-effective, compact, and operational robust solutions must be available. This paper discusses patented LNG fuel system designs and gives a qualitative evaluation of them with respect to their application to this ship segment. The use of a pressure build-up unit in combination with nitrogen injection, and/or heating of the LNG during bunkering, is suggested to be a feasible solution. Another aim of this paper is to highlight the role of patents within this area and contribute to the prevention of patent infringement. [ABSTRACT FROM AUTHOR]

Freight transport decarbonization is challenging due to the slow implementation of policies to meet climate goals. This paper analyzes the dynamics of the implementation of freight decarbonization measures. A System Dynamics model was developed and applied to the Brazilian freight system to simulate the use of more sustainable modes and means of transport, including electrification, increased use of biofuels, acceleration of fleet renewal, and modal shift. Significant emission reductions are found in the scenarios combining a shift to alternative modes and a rapid phase-out of diesel vehicles. Even so, the Brazilian freight sector's emission budgets towards limiting global warming to 1.5 °C and 2 °C will be depleted during the current and next decade, respectively. An absolute reduction of carbon emissions before 2050 seems unlikely. Besides confirming the need to study the dynamics of the freight system, the findings corroborate the urgency for stronger actions on freight decarbonization. [ABSTRACT FROM AUTHOR]

The lack of information on trip purpose and alternative mode in micromobility service usage data remains a major analytical challenge. Conventional survey method is subject to significant sampling and stated preference biases. To overcome this challenge, this paper presents a new inference method through a case study of rental e-scooters in London. The inference method features a rule-based algorithm for matching observed rental e-scooter trips with filtered trip samples in the English National Travel Survey (NTS) series. Probability distribution of trip purposes and alternative modes are then retrieved from NTS. Inference results are validated using official data. Discrepancies, sources of biases and correction measures are investigated. Based on the inferred mode substitution pattern, we estimate greenhouse gas emissions reduction of selected rental e-scooter trips in London (36–103 g CO 2 e per mile). It is expected that the proposed method is applicable to a wide range of micromobility studies using service usage data. [ABSTRACT FROM AUTHOR]

• One of the most sparsely populated areas in Europe. • Long distances to services and other destinations for daily activities. • Two villages were selected due to ongoing DiSS initiatives. • The results support the idea that DiSS could be a viable solution to mitigate and counteract accessibility poverty in rural areas. • DiSS for reducing long-distance private car journeys in reducing greenhouse gas emissions. • Essential to support older people in adopting digital solutions for a more sustainable digital transition. Norrbotten region is one of the most sparsely populated areas in Europe, with often long distances to services. This paper aims to gain a deeper understanding of the everyday mobilities in later life in rural areas, and to assess to what extent digital service solutions (DiSS) can contribute to reduced accessibility poverty. The study focuses on how DiSS contribute to more equitable accessibility by means of a case study in two villages, selected due to implemented DiSS (store with digital locks, digital hubs, etc.). Interviews with older people and other informants show the potential of DiSS to counteract accessibility poverty by bringing services nearer to home and reducing the need for longer trips, while contributing to the creation of healthier and more resilient environments. If implemented carefully, DiSS can have the potential to contribute to the development of more transport-efficient and socially just societies. [ABSTRACT FROM AUTHOR]

Shore power (SP) is a key technology to reduce emissions in a port. The deployment of SP has faced a significant challenge due to its high management costs. This study aims to compare various incentive policies that can promote SP from the perspectives of pollutant penalty, berth allocation, construction subsidy, electricity subsidy, and their combinations. To identify effective incentive policies for wide use of SP from both sides, this paper develops a cost-minimizing nonlinear mixed-integer programming model. The model optimizes decisions regarding SP deployment, berth allocation, and ship service sorting simultaneously. The performance of these incentive policies is evaluated in a bulk terminal scenario. Sensitivity analysis of key parameters was conducted to examine the impact of policies. The results show that all the proposed policies can effectively promote SP use and emissions reduction. Policymakers are recommended to implement a mixed incentive policy instead of a single incentive policy. [ABSTRACT FROM AUTHOR]

The increasing of carbon emissions due to traffic congestion in urban centers has been plaguing city managers. Park-and-Ride system are considered as important solutions to reduce urban carbon emissions. However, research on parking reservation on park-and-ride systems is still insufficient. Therefore, this paper explores the impact of parking reservation mechanisms on park-and-ride systems. A multi-modal agent-based network model is constructed to simulate the park-and-ride behavior, different parking reservation strategies are assessed and optimized which aim to minimize carbon emissions. Taking the Suzhou Guanqian Street Commercial District, China as the numerical example, we analyzed the impact of parking space allocation on carbon emissions. When parking spaces are reserved in proportion to demand, emissions decrease until a 70% reservation ratio. Beyond this threshold, emissions increase. Employing Genetic Algorithm (G.A.) to optimize the allocation of reserved parking spaces in each parking lot can further reduce carbon emissions. [ABSTRACT FROM AUTHOR]

Policy-makers are investigating ways to reduce greenhouse gas emissions of the transportation sector. Many government agencies have studied the effects of pavement type and characteristics on fuel consumption. Such models, valid for a particular set of simulation conditions, suggest that rigid pavements perform better than flexible pavements. However, it is unclear how this type of model can be applied at the scale of a realistic road network. This paper proposes a statistical approach to assess the relative importance of pavement type and characteristics on fuel consumption of heavy vehicle traffic by considering the specificities of meteorological conditions, heavy vehicles, and driver behaviours. A case study in Canada showed that the potential advantage of using rigid pavements was offset by cold climate effects and the consideration of a realistic statistical payload distribution. Road roughness accounted on average for 1.1% of total fuel consumption, with an increased value of 1.9% in January. [ABSTRACT FROM AUTHOR]

Using ammonia as an alternative marine fuel has been gaining interest in reducing greenhouse gas emissions in the maritime sector. This paper describes the development of a discrete event simulation model for bunker supply chain, emphasising how ammonia bunkering affects the operational and economic performance of the system. The results show that the model is a useful tool for ammonia bunker supply chain management, including the selection of the number and capacity of ammonia bunker supply vessels, bunkering flow rate and ammonia demand. Flow rate has a significant impact on bunkering service time, with an effect of up to 51.3% when it is changed by ±50%. The greater the demand for ammonia, the more significant the impact of ammonia bunkering flow rate on bunkering service time. Moreover, the number of ammonia bunker supply vessels is the most sensitive parameter for annual operational cost, with an effect of up to 15.2%. [ABSTRACT FROM AUTHOR]

Although operational activities in the aviation sector inevitably bring more emissions, they also reshape the structure of the regional economy, and often upgrade emission-heavy industries to cleaner service sectors. Thus, the overall impact of aviation network development on the region's environmental trajectory is unclear, and calls for rigorous empirical study. Using the data of 283 Chinese prefecture-level cities for the period 2003–2017, this paper proposes and calculates a comprehensive "carbon lock-in" index to measure cities' reliance on emission-heavy sectors and resistance to emission reduction. Then, we calculate cities' air connectivity and network centrality to measure the aviation development, and also examine their direct, indirect, as well as heterogeneous impacts on cities' carbon lock-in. Our empirical results suggest that an improved aviation network development helps alleviate carbon lock-in. Mechanism analysis further reveals that fixed input, industrial structure upgrading, and technological innovation are the three underlying channels. [ABSTRACT FROM AUTHOR]

• The top 5% of car users travel nearly 27,500 miles (4.8 times the average) and emit 5742 kg CO 2 annually (5.7 times the average). • The top 20% of car users in England travel 16,740 miles and emit 3200 kg CO 2 annually. • Male, high-income professionals and large car owners are more likely to record higher mileage. • Rationing the top 5% of car users would reduce emissions by 6.9% whilst rationing the top 20% would lead to reductions of 26%. • Rationing high CO2 emitters directly is more effective than rationing car mileage. This paper measures 'excess' car travel for its role in decarbonisation. On average, each English adult travels around 5,680 miles a year and emits 1,006 kg of CO 2. However, the top 5% 'excess' car users travel 4.8 times and emit 5.7 times the national average. Four binary logistic regression analyses were used to model the probability that people with specified characteristics belong to the 'excess' mileage and emitter groups. Results indicated that gender, employment and socio-economic status, household income (higher quintiles), company car availability, residential location and local population density were highly significant correlates of this 'excess' travel mileage. Multiple car ownership, business travel by car, multiple international flight frequencies and ownership of larger and diesel cars were positively associated with excess travel and emissions. A mileage rationing scheme targeting the top 20% users can cut emissions substantially (by 26%) compared to targeting 'excess' (top 5%) users only. [ABSTRACT FROM AUTHOR]

[Display omitted] This paper assessed the impact of five different WMA additives categorized under organic, chemical and foaming-based technologies on the energy requirement and green house gas (GHG) emissions. The maximum bearable cost, corresponding to different additives, was determined to assess the optimal choice of warm mix technologies. Results demonstrated that the addition of WMA additives lowers the heat energy by 3–12% compared to HMA. Although diesel is the most expensive fuel (considered in this study), its use can offset the cost of additives, for some WMA additives, namely: SR0.7, C0.2, C0.35, and R0.4. Calculations indicated that among the various warm mix additives, Sasobit Redux produces least emissions, followed by Aspha-min, Rediset, Sasobit, Cecabase, and viscosity graded binder. It was concluded that the use of WMA technologies can provide possible cost savings, and reduction in GHG emissions. [ABSTRACT FROM AUTHOR]

The pressure on shipping to reduce its carbon footprint is increasing. Various measures are being proposed at the International Maritime Organization (IMO), including Market-Based Measures (MBMs). This paper investigates the potential of a bunker levy in achieving short-term CO 2 emissions reductions. The analysis focuses on the tanker market and uses data from the latest IMO GHG studies and a variety of other sources. The connection between fuel prices and freight rates on the one hand and vessel speeds on the other is investigated for the period 2010–2018. A model to find a tanker's optimal laden and ballast speeds is also developed and applied to a variety of scenarios. Results show that a bunker levy, depending on the scenario, can lead to short-term CO 2 emissions reductions of up to 43%. Policy implications are also discussed, particularly vis-à-vis recent IMO and European Union (EU) action on MBMs. • Some properties of the tanker speed optimization problem are investigated. • We use data from GHG studies and several other sources to compute CO 2 emissions. • The link between speed and the ratio of spot rate by fuel price is investigated. • A bunker levy can reduce CO 2 emissions from tankers up to 43% in the short-term. • The IMO 50% GHG reduction target is unreachable via slow steaming induced by a levy. [ABSTRACT FROM AUTHOR]

• Propose a novel approach to reduce sulphur emissions, which can be trade enhancing. • Investment in supply chain performance can reduce emissions via indirect mechanisms. • Emission targets achieved by promoting trade and using larger vessels to move goods. • A combination of an augmented gravity equation and econometric models are applied. • The proposed indirect mechanism is complementary to the IMO sulphur emissions cap. This paper proposes a novel way to reduce sulphur emissions in international transport, by focusing on the role of logistics improvements and vessel size. Using an augmented gravity model and advanced econometric methods, we assess the impact of logistics performance on bilateral trade, and then evaluate the link between bilateral trade and vessel size. The estimation results are translated in terms of sulphur emission reduction. The models are estimated on an original panel data set composed of worldwide bilateral trade of manufactured goods, several characteristics of container vessels and maritime routes, and indicators of logistics performance. We show that investing in logistics improvements can generate trade growth, and reduce sulphur emissions per unit of goods transported by promoting the utilization of larger and more fuel-efficient vessels. The proposed indirect mechanism is complementary to the current sulphur emissions cap, and allows decision-makers to reduce emissions which can be trade enhancing. [ABSTRACT FROM AUTHOR]