Transport Research International Documentation (TRID)

Assessing Sweden’s Greenhouse Gas Emissions from Road Maintenance using Environmental Product Declarations and Network Life-Cycle Optimization

Fri, 17 Apr 2026 08:57:14 GMT

To achieve the Paris Agreement’s goal of limiting the average temperature rise to 1.5°C, greenhouse gas emissions must be reduced by 43% from 2010 levels by 2030. This paper quantifies greenhouse gas emissions from road maintenance in Sweden and evaluates reduction pathways by integrating three elements: (1) lifetime estimates of maintenance operations, (2) corresponding emissions estimated from published Environmental Product Declarations, and (3) simulation of a 10-year maintenance plan that maintains current condition distribution at minimum cost across three regions (Stockholm, Skåne, Norrbotten). We assess three scenarios: a 2010 fossil-fuel baseline; a 2024 practice with predominantly biofuel-fired production and higher reclaimed asphalt utilization; and a 2024 extension that additionally replaces 5% of bitumen with a biogenic binder and employs biofuels for transport and machinery. Relative to 2010, the simulated emissions required to maintain current network condition were 28% to 30% lower under 2024 practices and 60% to 61% lower with added biogenic binder. The largest emission reductions arose from switching production heat from fossil to biofuels and from increased reclaimed asphalt. Total life-cycle impacts remained sensitive to treatment longevity, underscoring the need to integrate performance into procurement and to monitor the durability of emerging low-carbon materials. Although Sweden has reduced emissions substantially, achieving the 43% reduction target by 2030 will require measures beyond current practice.

Energy and Operational Efficiency of Shared Autonomous Fleet Powered with Battery Electric and Internal Combustion Engine Technologies

Tue, 14 Apr 2026 15:11:25 GMT

Electrifying shared autonomous fleets (Robotaxis) presents challenges in balancing decarbonization, service quality, and operational costs, given the limited driving range, long charging times, and suboptimal planning of charging infrastructure. This study develops an integrated energy management and fleet dispatching simulation framework to support cost-effective, low-carbon Robotaxi deployment. The proposed system models both battery electric vehicles (BEV) and internal combustion engine vehicles (ICEV) technologies, and is extensible to other powertrain types. The study also integrates a life cycle assessment module to evaluate well-to-wheel carbon emissions. A total of 1,440 scenarios are designed to test the performance of two service modes (ride-hailing vs. ride-pooling) in terms of energy consumption, emissions, service quality, and operational costs, across varying levels of trip demand and market penetration of different powertrain technologies. The testing aims to verify the system’s effectiveness in improving energy efficiency, clarify the cost of autonomous vehicles electrification, and identify the most cost-effective low-carbon fleet composition under different scenarios. The results demonstrate that ride-pooling system outperforms both ride-hailing and private vehicles. Ride-pooling achieves 15–25% lower carbon intensity and 18–25% energy savings compared to private vehicles. It is also found that EVs present, on average, an 8–12% higher trip rejection rate than ICE fleets, demonstrating that electrifying Robotaxis comes at the cost of reduced service levels or increased costs. The study ultimately finds that electrifying Robotaxis at a moderate level (40–60%) can achieve a good trade-off between environmental benefits, service quality, and cost.

Cradle-To-Grave Assessment of Austrian Passenger Car Traffic based on Actual Vehicle Movements and Derivation of Future Forecasts for Minimising Greenhouse Gas Emissions

Tue, 14 Apr 2026 15:11:24 GMT

As part of the decarbonisation process for passenger car fleet in Austria, battery electric cars in particular have been subsidised in recent years, as these vehicles are considered to be largely emission free during use and are expected to reduce emissions in future. However, in order to sustainably reduce the global greenhouse gas emissions of Austrian passenger car traffic, taking into account all types of fuel systems, it is necessary to apply a cradle-to-grave approach, as is commonly done in comparable analyses in the literature, which evaluates the emissions of the entire vehicle life cycle. The most important phase in the life cycle assessment remains the well-to-wheel phase, which includes emissions from energy supply and vehicle use. Due to the large number of influencing factors, highly simplified models are usually used for this phase in the literature. As part of this work, a methodology was developed that, allows an in-depth analysis of entire vehicle fleets by linking real vehicle movements with emissions data and energy consumption. By using real vehicle movements, environmental conditions (ambient temperature, etc.) and traffic situations (traffic jams, etc.) can be integrated into the emissions assessment. To capture the influencing factors more realistically, the assessment is performed at hourly rather than annual time intervals, unlike most previous studies. This new approach provides therefore a more detailed and realistic cradle-to-grave analysis of the Austrian passenger car fleet, making it possible to test individual measures in future scenarios and to define a coordinated strategy for minimizing the fleet’s future global greenhouse gas emissions.

Mechanical Performance and Life Cycle Assessment of Semiflexible Pavement Using Sustainable Grout

Tue, 14 Apr 2026 14:32:30 GMT

The efficient utilization of construction waste in road engineering is essential for advancing sustainable infrastructure development. This study explores the application of ceramic waste powder (CWP) in cementitious grout for semiflexible pavement (SFP) surfaces. Cement was partially replaced with CWP at proportions ranging from 15% to 50%, and its effects on SFP performance and environmental impact were evaluated using compressive strength testing, life cycle assessment (LCA), and statistical analysis. The obtained SFP mixtures were assessed for volumetric and mechanical properties through Marshall stability and wheel tracking tests. Experimental findings revealed that 20% cement replacement with CWP was the optimal level, leading to an 80% reduction in rutting depth and increases of 50% and 23% in compressive strength and Marshall stability, respectively, at 28 days of curing. These improvements are attributed to CWP’s superior fluidity in filling the voids within the porous asphalt skeleton and its effective bonding capacity with aggregates, which densifies the microstructure, as confirmed by scanning electron microscopy (SEM) analysis. LCA results indicated that higher CWP replacement levels reduced both global warming potential and fossil fuel depletion, thereby enhancing the grout’s sustainability. Statistical analyses, including quadratic regression, ANOVA (p<0.05), and the Tukey HSD test, confirmed significant improvements in strength properties with CWP incorporation, whereas box plots effectively illustrated data trends and variations. In summary, this study underscores the dual environmental and performance benefits of incorporating CWP in SFP systems and supports its adoption in sustainable road construction aligned with circular economy goals.

Sulfate Freeze–Thaw Damage Evolution and Life Prediction of Recycled Concrete Based on Entropy Weight Method and Grey Theory

Fri, 10 Apr 2026 16:00:15 GMT

The effects of recycled coarse aggregate (RCA) replacement rate, freeze–thaw environment, and cycle number on the durability of recycled coarse aggregate self-compacting concrete (RCASCC) were experimentally investigated. Compressive strength, splitting tensile strength, uniaxial compressive strength loss, and ultrasonic wave velocity loss were analyzed. Results show that within 0–50 freeze–thaw cycles, strength loss of R0, R50, and R100 exhibited no significant differences across four environments, whereas clear stratification appeared during 50–125 cycles. As cycles increased, the splitting tensile strength loss curve gradually flattened, while ultrasonic wave velocity loss reached a minimum between 50 and 75 cycles. Among all environments, 5 wt% MgSO4 solution caused the most severe deterioration. Based on entropy weight theory, a durability evaluation index was established, showing a decreasing trend with increasing cycles and a stratified distribution among groups. The GM(1, 1), Verhulst, and parabolic regression models demonstrated high prediction accuracy, while GM(1, N) performed poorly. Using Inner Mongolia as a case study, service life under combined freeze–thaw and sulfate attack was predicted, with the Verhulst model providing more conservative estimates. Furthermore, a BP neural network optimized by GM(1, 1) and Verhulst models was developed. Compared with GM(1, 1), the Verhulst-optimized BP model showed superior prediction accuracy and generalization ability.

Comprehensive Study on Modification Mechanism of Waterborne Epoxy Resin Emulsified Asphalt and Life Cycle Benefits of Its Mixture

Thu, 02 Apr 2026 15:23:59 GMT

This study focuses on the lack of systematic research on the effects and mechanisms of waterborne epoxy resin (WER) and curing agents on emulsified asphalt, as well as the challenge of scientifically evaluating the comprehensive benefits of waterborne epoxy resin emulsified asphalt (WEREA) and its mixtures. Nine WER bicomponents were chosen to modify emulsified asphalt, with properties studied at the macro and micro levels. A modification mechanism model for WEREA was developed. Then, 75 indicators were selected to assess the rheological properties of WEREA and mixture performance using the efficiency coefficient method to construct an evaluation index system. The performance–environmental–economic benefits of the WEREA mixture were verified based on life cycle analysis. This study confirmed the performance dominance of WEREA and its mixtures in high-temperature environments. The WER with an epoxy value of 0.2 eq/100 g and the curing agent containing four amino groups had the most significant effect on optimizing the performance of WEREA, especially when the dosage of the WER was 15%. The WEREA mixture prepared with that WER bicomponent had the best performance, economic, and environmental benefits when the oil–stone ratio was 9.07%. The environmental benefits account for 46% of the overall life cycle benefits of the WEREA mixtures, emphasizing the importance of controlling pollution emissions for sustainable pavement construction.

Differentiated fatigue damage characteristics and life prediction of asphalt mixtures under actual service conditions

Wed, 01 Apr 2026 11:46:20 GMT

Accurate fatigue life prediction for asphalt pavements is crucial for developing maintenance strategies and extending service life. However, existing methods remain limited in addressing diverse damage characteristics from varying traffic loads and structural positions. This paper conducted core sampling from driving lanes and shoulders, obtaining specimens from wearing and binder courses. Fatigue performance was systematically evaluated through indirect tensile fatigue testing using classical and dissipated energy-based analysis under different stress ratios. Results demonstrate that mixture modulus evolution exhibits remarkable consistency across stress ratios, characterized by two phases: initial steady decline followed by rapid deterioration. Mixtures from different layers and positions display consistent evolution characteristics. More significantly, three dissipated energy indicators (Initial DE, PV, and Cumulative DE) show strong linear correlations with fatigue life in double logarithmic coordinates. Unlike conventional prediction equations, these indicators demonstrate insensitivity to structural layer and position. Consequently, dissipated energy-based indicators enable unified prediction equations unaffected by loading conditions, sampling positions, or structural layers. These findings suggest dissipated energy approaches, particularly Initial DE, offer more efficient fatigue assessment with reduced testing requirements.

Cycle-efficient modeling for degradation staging and early life prediction of lithium batteries

Fri, 27 Mar 2026 10:20:35 GMT

An effective and time-saving early life prediction model is crucial for rapid battery assessment. However, existing models face a dilemma: they either rely heavily on extensive historical data or provide limited predictive insights into battery degradation. To address this, this study proposes a cycle-efficient battery life assessment framework integrating data-driven and empirical models. The framework consists of two components: degradation stage detection relying solely on data from one cycle and early life prediction using five-cycle data. The early life prediction model is capable of achieving joint prediction of the battery's remaining useful life and the cycle to knee point. Experimental results demonstrate that the degradation staging model achieves an accuracy of 0.977,6 for lithium iron phosphate batteries. Meanwhile, the early life prediction model yields mean absolute percentage errors of 10.5% for remaining useful life and 12.8% for the cycle to knee predictions. The model's accuracy and generalizability have been validated across diverse battery types, health states, and operating conditions. This proposed framework exhibits excellent generalizability capability under all evaluated scenarios, establishing a robust foundation for rapid battery design assessment and retirement decisions.

Performance-informed life cycle assessment of waste-derived asphalt mixtures for full aggregate replacement

Thu, 26 Mar 2026 09:05:15 GMT

Increasing the circularity of asphalt pavements through industrial by-products and reclaimed asphalt pavement (RAP) offers a practical route to reduce reliance on virgin aggregates and the associated upstream burdens. This study presents an integrated sustainability evaluation of steel slag-RAP asphalt mixtures designed for full aggregate replacement, combining laboratory performance characterisation with a performance-informed life cycle assessment (LCA). Laboratory testing covered key road-performance attributes, complemented by immersion conditioning and trace-element leaching to examine long-term feasibility and environmental safety. A high-functionality epoxy slag-RAP mixture was identified through performance screening and adopted as the representative full-replacement option for scenario parameterisation. The LCA quantified seven impact categories and a monetised ecological cost indicator, with results interpreted under a functionally consistent 30-year comparison. Under this comparison, the full-replacement option reduced global warming potential from 146.01 to 89.42 t CO₂-eq (−38.8%) and acidification from 0.58 to 0.36 t SO₂-eq (−37.9%) relative to a conventional natural-aggregate reference, with the benefits arising from both waste-based aggregate substitution and reduced intervention frequency enabled by improved durability; trade-offs were observed in eutrophication and toxicity-related indicators. Total ecological cost decreased from 182.30 × 103 CNY for the conventional reference to 113.59 × 103 CNY for the full-replacement option. By integrating performance-based service-life parameterisation with multi-category life cycle impact and ecological-cost monetisation, the proposed framework supports a more accurate and comprehensive evaluation of recycling-based pavement strategies and can be transferred to other infrastructure applications, while confirming that full replacement of natural aggregates by waste-derived materials can deliver substantial net life-cycle benefits.

Decarbonizing transportation through electric vehicles: A life cycle perspective across China, Europe, and the USA

Wed, 25 Mar 2026 11:44:54 GMT

Over the past decades, the use of electric vehicles (EVs) has steadily increased as many countries promote EVs to replace internal combustion engine vehicles (ICEVs) to reduce greenhouse gas (GHG) emissions in the transportation sector. This study employs the life cycle assessment (LCA) software SimaPro 9.5, integrated with the Ecoinvent 3.9.1 database, to quantify and compare the GHG emissions of battery electric vehicles (BEVs) and ICEVs in China, Europe and USA. A cradle-to-grave (CTG) system is adopted, encompassing vehicle manufacturing, energy production, use, and end-of-life (EoL) treatment. Also, Optimization scenarios for BEV operation are explored by considering electricity mix, battery use strategies, and total driving mileage over the vehicle's lifetime. Under optimization scenario, BEVs can reduce GHG emissions by 0.25, 0.18 and 0.26 kg CO₂ equivalent (CO₂-eq) per vehicle per kilometer compared to ICEVs baseline scenario in China, Europe and the USA, respectively. According to Stated Policies Scenario (STEPS) and optimal BEV scenario, compared with ICEVs baseline scenario, BEVs are projected to achieve the maximum GHG reductions by 2030 in China, Europe, and the USA, reaching approximately 254.7, 76.8, and 55.0 Tg CO₂-eq, respectively, regardless of whether the model-defined default annual mileage or empirically observed annual driving distances are used. Meanwhile, this study evaluates the influence of policy orientation and automotive industry development trends on the future GHG emission reductions potential of BEVs, with the aim of providing decision-making support for optimizing low-carbon transportation pathways.

Bridging the gap: A review of simulation approaches in multipurpose Shipyard integrating shipbuilding, repair, and recycling

Wed, 25 Mar 2026 11:44:54 GMT

Shipyards increasingly combine shipbuilding, repair, and recycling within shared facilities, yet most simulation research still treats these activities separately, limiting support for operational integration and lifecycle-oriented decision-making. Multipurpose shipyards in emerging maritime economies face challenges in coordinating shared docks, cranes, and labour under changing market conditions and sustainability pressures. This study reviews how simulation has been applied across shipbuilding, repair, and recycling, and assesses whether existing models support integrated multipurpose yard operations. A systematic review following the PRISMA guidelines analysed 215 peer-reviewed (2003–2024) from Web of Science and Scopus, coded by activity focus, simulation paradigm, integration scope, and research objectives. Results show 88 % of studies concentrate on shipbuilding, 7 % on repair, and 2 % on recycling, with only 3.7 % addressing multiple activities and none representing all three concurrently in a unified simulation architecture. Discrete Event Simulation dominates, while hybrid, Digital Twin, and lifecycle-oriented approaches remain limited, particularly for shared resource and sustainability applications. The review identifies six major gaps: activity integration, resource conflict resolution, prioritisation, trade-offs, lifecycle links, and decarbonisation. It contributes a comparative taxonomy of simulation paradigms and a five-layer framework that linking physical resources, processes, integration mechanisms, decision support, and learning/adaptation to guide future multipurpose simulation research.

Comparative life cycle carbon footprints of buy online pick up in-store retail

Wed, 25 Mar 2026 11:44:49 GMT

Escalating consumer demands for immediacy and flexibility has driven hybrid retail strategies such as Buy Online, Pick Up in Store (BOPIS). While convenient, it may increase environmental burdens, warranting systematic assessment. This study conducts a cradle-to-grave life cycle assessment comparing greenhouse gas emissions across in-store, online, and BOPIS retail. Results show that upstream manufacturing dominates emissions for three strategies. BOPIS exhibits a per-basket carbon footprint of 57.25 kg CO₂eq (95% CI: 50.56–64.04), which is comparable to in-store retail given substantial overlap in uncertainty ranges, while 50.91% higher than online retail, due to additional consumer travel (12.51–30.85%) and in-store energy use (up to 13.52%). In the United States, longer travel distances amplify impacts, with BOPIS exceeding the European Union countries averages by 5–54%. Across 2023 cross-country data, higher Logistics Performance Index values correlate with lower emissions (r = -0.67). Findings highlight the actionable levers including improving logistics efficiency, promoting trip substitution for pickup, and decarbonizing energy supply to reduce emissions across retail strategies.

Techno-economic and environmental impact assessment of chemical absorption based shipboard carbon capture and storage

Wed, 25 Mar 2026 11:44:47 GMT

Shipboard carbon capture and storage (SCCS) is a viable retrofit for maritime decarbonisation, yet its environmental and techno-economic performance remains under-quantified. This study links life-cycle assessment with life-cycle costing to evaluate SCCS across four fuel configurations comprising very low sulphur fuel oil (VLSFO), marine gas oil (MGO), liquefied natural gas (LNG), and methanol, analysed with/without capture. Fuel system boundaries follow International Maritime Organization guidance. The SCCS boundary covers post-combustion monoethanolamine (MEA) absorption, compression/liquefaction and onboard liquid CO₂ storage; one-off manufacture/transport/installation and periodic maintenance are included, whereas port offloading and downstream transport, storage or utilisation are excluded. To enhance generalisability, conservative settings are adopted, assuming post-combustion monoethanolamine at 1.5 kg/t CO₂, 58% capture efficiency, 3.7 GJ/t CO₂ energy use, and a 30-year service life with 5-year maintenance. Under these settings, installing SCCS lowers well-to-propeller greenhouse-gas emissions by 48.8–49.5% across all fuels after including 8.5–9.2% SCCS self-emissions. These net reductions support technical feasibility through policy alignment, with attained Energy Efficiency Existing Ship Index decreasing and Carbon Intensity Indicator improving by up to two grades for representative container, bulk-carrier, and tanker vessels. MGO with SCCS attains decarbonisation comparable to methanol, hence the economic comparison focuses on these two pathways. Over 30 years, MGO with SCCS is 7.1% less costly, with fuel prices the primary driver. Probabilistic analysis indicates SCCS on MGO is the lower-cost option in 69.8% of cases. Overall, within the stated boundary, the findings demonstrate the significance and effectiveness of SCCS for ship decarbonisation.

A Review on Flexible Pavement Performance Life Assessment

Mon, 23 Mar 2026 15:24:24 GMT

Accurate assessment of pavement performance life is the cornerstone of pavement management system. During the last decades, many pavement life expectancy models relying on various concepts from purely empirical to truly mechanistic have been developed. However, the lack of adequate systematic and efficient model classification system and analysis has been the major barrier for further research on pavement life expectancy. This paper performs an in-depth review on flexible pavement life prediction models and addresses a new model classification method that can facilitate the model-selection for pavement engineers.

Towards Sustainable Cycling: Life Cycle Assessment of bicycle road pavement

Mon, 23 Mar 2026 15:15:34 GMT

It’s an undeniable truth that the environmental impacts of bicycle road infrastructure are crucial, given a hundred kilometres of roads paved with asphalt. However, the environmental impact of asphalt concrete have not been fully determined. Recently, significant research and surveys are being conducted, which recognize the importance of the global warming potential (GWP) impacts of bicycle roads. In this context, the aim of this study is to evaluate the GWP impact of asphalt concrete by using raw materials and combining it with reclaimed asphalt aggregate (RAP) in two different percentages (20%) and (40%) to determine the benefit of using RAP and it impact on the to reduction of construction CO2 emissions. Within the framework of this study, a hypothetical case using the life cycle assessment methodology was conducted. The life cycles of asphalt concrete (AC) and AC combined with RAP were comparatively assessed limited with material production phase, and it was determined which alternative has fewer GWP impacts during this phase. It was noticed that the AC combined with 40% of RAP has the fewest GWP compared to the AC with virgin material.