Comprehensive Transportation Research Articles

Essential not Supplemental: Medicare Advantage Members’ Use of Non-Emergency Medical Transportation (NEMT)

BackgroundOver five million people in the USA miss or delay medical care because of a lack of transportation. Transportation barriers are especially relevant to Medicare Advantage (MA) health plan enrollees, who are more likely to live with multiple chronic conditions and experience mobility challenges. Non-Emergency Medical Transportation (NEMT) helps to address transportation gaps by providing rides to and from routine medical care (for example, medical appointments, laboratory tests, and pharmacy visits) and has been added as a supplemental benefit to some MA health plans.ObjectiveWe aimed to characterize MA enrollees’ experiences with supplemental NEMT benefits.DesignQualitative interviews focused on participants’ experiences with existing NEMT benefits, transportation, and mobility.ParticipantsTwenty-one MA enrollees who used their MA NEMT benefit in 2019 and who remained eligible for ongoing transportation benefits through 2021.ApproachUsing purposive sampling from a list of eligible participants, we recruited individuals who used their MA NEMT benefit in 2019 and who remained eligible for benefit-covered transportation services through 2021.Key ResultsParticipants considered NEMT an essential service, particularly because these services helped them decrease social isolation, reduce financial insecurity, and manage their own medical needs. Navigating logistical challenges associated with arranging NEMT services required participants to commit considerable time and energy and limited the effectiveness and reliability of NEMT.ConclusionParticipants described NEMT as a valued service essential to their ability to access health care. They suggested ways to increase service flexibility and reliability that could inform future NEMT policy and practice. As health systems and payers learn how to best address social risks, particularly as the US population ages, our findings underscore the importance of NEMT services and highlight opportunities to advance comprehensive transportation solutions for MA participants.

Modeling of local mass transport in cathode catalyst layer of proton exchange membrane fuel cell: Catalyst partially covered by ionomer

An in-depth understanding of the local mass transport process is essential for precisely regulating the catalyst layer structure in fuel cells. The ionomer on the Pt surface in the catalyst plays a crucial role in the local transport of oxygen and protons. While most models assume that Pt is completely covered by ionomer, experiments have indicated that Pt is partially covered by ionomer in some cause. In this paper, an improved local mass transport model is proposed to investigate the effect of ionomer coverage on internal mass transport process and fuel cell performance. The results show that the current density first increases and then decreases as the ionomer coverage rises from 10% to 90% under 0.6 V. The optimal performance is achieved with a coverage of 40%. Oxygen is more easily transported in water, while ionomer is a better proton conductor. Variations in ionomer coverage lead to different distances for oxygen and proton transfer, which have an important effect on reactant concentration. Furthermore, further study reveals that the current density is greatest at the interface between water and ionomer. Increasing the interface can effectively reduce the comprehensive transport distance of reactants in ionomer and water to improve performance, which is more pronounced than increasing the oxygen transfer coefficient in the ionomer. Overall, this study provides new ideas for the design of high-performance catalyst layers.

Design of a High-Speed Railway Passenger Train Operation Scheme considering Survivability of the Network

As an important part of modern comprehensive transportation system, high-speed railway (HSR), whether it is a transregional trunk line or an intercity line, always shapes the industrial layout and changes the living environment at different levels. Based on the analysis of the railway network topology and organization process of passenger train, this paper clarifies the connotation of passenger train operation scheme of HSR considering network survivability, and further explains the connotation of railway network system and its relationship with passenger train operation scheme. In this paper, a comprehensive quantitative index of the importance of key nodes and key edges is established, and an evaluation index of the survivability of railway service network based on the operating mileage of passenger trains is constructed, which is applied to the real local HSR network in China. With the aim of improving the survivability of HSR system, an alternative operation route of passenger trains between some OD stations is given according to the specific railway interruption situation.

Recent Advances in Functionalized Fullerenes in Perovskite Solar Cells†

Comprehensive SummaryEfficient charge transport and defect passivation are essential for high efficiency of organic–inorganic hybrid perovskite solar cells (PSCs). Functionalized fullerenes featuring high electron affinity and mobility as well as small reorganization energy have been extensively applied in PSCs toward facilitated electron transport and passivated trap states, leading to improvements of both device efficiency and stability. Herein, we summarize the recent advances, especially in the last three years, in applications of functionalized fullerenes including fullerene derivatives and endohedral metallofullerenes in PSCs. Their functions in trap state passivation, electron transport promotion, crystalline modulation, water/oxygen erosion inhibition, and so on, are discussed in details. In particular, we emphasize novel functions of fullerenes beyond trap state passivation, as well as the synergy of multifunction of fullerenes in improving PSC device performance and stability. Finally, we present an outlook on designing novel multifunctionalized fullerenes toward highly efficient and stable PSC devices.

Two steps forward, one step back? Party competition, cooperative federalism, and transport policy reforms in Germany

BackgroundTransport policy has regained political relevance in Germany. The successful realization of the Verkehrswende,—the extensive transition toward sustainable transport and mobility—is central to reaching climate neutrality. In 2020, the Federal Government proposed the reform of two key ordinances that have regulated road traffic so far. The amendment was aimed at implementing several provisions at the expense of car drivers and, at the same time, in favor of cyclists and pedestrians. Due to cooperative federalism, the governments of the 16 constituent units (Länder) had to adopt the amendment in the Bundesrat, Germany’s second chamber. In the legislative process, however, the reform ultimately failed in its original scope. Using it as a particularly instructive case study, we show how and why party competition and cooperative federalism hamper comprehensive transport policy reforms in Germany.ResultsIn the German political system, political interests interact within a complex web of cooperative federalism. To understand partisan encroachment on the federal decision-making processes, this paper uses a process-tracing approach. To investigate decision-making in the Bundesrat and its outcomes, the empirical analysis combines qualitative analyses of several publicly available sources. We can empirically demonstrate that political parties influenced legislative procedures. The reform failed in its original scope because the three political parties with veto power in the Bundesrat insisted on their positions and were not willing to agree on a compromise.ConclusionsFor the implementation of the Verkehrswende, the German federal system proves to be both a blessing and a curse. On one hand, the institutional design of the Bundesrat constrains extreme positions and helps promote decisions most citizens may agree with. The Länder governments and administrations can also contribute their expertise and local experience to federal legislation via the Bundesrat. On the other hand, veto powers are ubiquitous in the German system of cooperative federalism. Therefore, it is prone to blockades. The actions of the political parties in the Bundesrat have hampered the comprehensive reform of road traffic regulations that was originally envisaged. Policymaking took two steps forward toward implementing the Verkehrswende, only to immediately take one step back again.

A spectral boundary integral method for simulating electrohydrodynamic flows in viscous drops

A weakly conducting liquid droplet immersed in another leaky dielectric liquid can exhibit rich dynamical behaviors under the effect of an applied electric field. Depending on material properties and field strength, the nonlinear coupling of interfacial charge transport and fluid flow can trigger electrohydrodynamic instabilities that lead to shape deformations and complex dynamics. We present a spectral boundary integral method to simulate droplet electrohydrodynamics in a uniform electric field. All physical variables, such as drop shape and interfacial charge density, are represented using spherical harmonic expansions. In addition to its exponential accuracy, the spectral representation affords a nondissipative dealiasing method required for numerical stability. A comprehensive charge transport model, valid under a wide range of electric field strengths, accounts for charge relaxation, Ohmic conduction, and surface charge convection by the flow. A shape reparametrization technique enables the exploration of significant droplet deformation regimes. For low-viscosity drops, the convection by the flow drives steep interfacial charge gradients near the drop equator. This introduces numerical ringing artifacts that we treat via a weighted spherical harmonic expansion, resulting in solution convergence. The method and simulations are validated against experimental data and analytical predictions in the axisymmetric Taylor and Quincke electrorotation regimes.

A flexible model-free tram signal priority method with a large coordination scope in China

Abstract Tram systems with the advantages of reliable operation, comfort, low emissions and moderate capacity have been quite popular in recent years in China. However, there are still problems with tram signal control (e.g. evaluation model, signal control strategies). In-depth analysis on existing operational issues of trams, calculation of two evaluation indexes, as well as a flexible model-free tram signal priority method were developed to deal with tram problems. Empirical research in Songjiang District, Shanghai shows that: (1) The function of the green extension strategy is limited with c.a. 10% tram priority improvement, while the optimal one can reach to 85% higher on average. (2) A scheme with a benefit for trams and with no negative impact, and even benefits, for general traffic can be realized. (3) The optimal solution is beneficial for intersections with a maximum c.a. 70% amelioration with delay decreasing from 132.7 s/vehicle to 40.89 s/vehicle, or from 104.77 s/capita to 22.31 s/capita. This paper has great significance for the signal optimization and safety of tram systems, even the development of a comprehensive transportation system for a city.

Low-Carbon Emission Demolition of an Existing Urban Bridge Based on SPMT Technology and Full Procedure Monitoring

Due to the need for comprehensive transportation hub construction, an existing bridge in a bustling urban area with an operation duration of 25 years was required to be demolished. Based on Life Cycle Assessment (LCA), this paper proposes a scheme of "Self-propelled modular transporter (SPMT) technology + large segment cutting" to compare the carbon emissions of demolition schemes qualitatively and quantitatively. To ensure structural safety during demolition, the finite element analysis was used to simulate the entire demolishing process, and measuring points were set up to monitor the deformation of the main girder in real time under various demolition conditions. The results indicate that the scheme of SPMT has the lowest carbon emissions during the demolition stage. Additionally, the long-term prestress loss shall be considered when demolishing existing bridges; the suggested 25% proportional value for the long-term prestress loss of the Caitian Bridge is appropriate, which is determined by comparing the calculated results from various formulas. The values of the calculated and measured deformations of the main girder under different working conditions are in good agreement, with errors mostly within 10% and a maximum of no more than 14.7%. The demolition of the entire bridge was completed in a total of 28 h with little noise and pollution, and the impact on daily traffic was avoided, proving that the proposed “SPMT technology + large segment cutting” scheme is safe, efficient, and achieves the goal of green, environmentally friendly, and rapid demolition.

Comprehensive Transportation Planning Oriented by Green TOD Mode under the Background of Dual Carbon

Since the reform and opening up, China's cities have entered a period of rapid development, and the planning and design methods that meet the needs are far behind the economic development speed. The influx of people and the development of the automobile industry have made the space of the city crowded, and the problems of urban traffic congestion have become increasingly prominent. In the era of accelerating urbanization, urban transportation design planning is more and more important, urban transportation design is a large system, this paper focuses on the green TOD model as the guide for introduction, through the analysis of the current urban transportation development challenges to put forward green transportation priority strategy, on this basis to introduce the relevant concepts of TOD mode and the combination of green transportation, and then by citing examples of Chengdu TOD development to summarize the problems solved by TOD, and finally make suggestions for urban transportation design.

Tuning Charge Transport of Oligopeptide Junctions via Interfacial Amino Acids†

Comprehensive SummaryThe charge transport through peptides can imitate the corresponding processes in more complicated proteins, enabling us to develop high‐performance bioelectronic devices and to understand the mechanisms of biomolecular recognition and information transfer. While charge transport modulation through individual peptides has been achieved via various covalent strategies, the intermolecular modulation is still very challenging, which may capture the charge transport between proteins. To tackle this challenge, we used well‐defined self‐assembled monolayers (SAMs) of oligopeptides as a model to imitate the interface of proteins and explored an interfacial amino acid strategy for charge transport modulation. We showed that non‐covalently interfaced charged amino acids (e.g., arginine) effectively attenuated the charge transport of glutamic acid terminated polyglycine peptide SAMs. By analyzing the relationship of the charge transport with the molecular frontier orbital relative to the Fermi energy level of the electrode, the molecule‐electrodes coupling (Γ), and the trends in skewness and kurtosis with voltage and the dielectric constant (εr), we showed that the attenuation was from the decreased Γ and the reduced polarizability. We present an efficient strategy to modulate the charge transport of oligopeptide‐SAM junctions by intermolecular interactions, which will advance our understanding of charge transport in biological systems and facilitate developing future electronics.

Adapting to the Impacts Posed by Climate Change: Applying the Climate Change Risk Indicator (CCRI) Framework in a Multi-Modal Transport System

Climate change has threatened the infrastructure, operation, policymaking, and other pivotal aspects of transport systems with the accelerating pace of extreme weather events. While a considerable amount of research and best practices have been conducted for transport adaptation to climate change impacts, there is still a wide gap in the systematic assessment of climate risks on all-round transport modes (i.e., road, rail, sea, and air) with a comprehensive review and a quantitative scientific framework. This study aimed to critically review studies on how the transport sector has adapted to the impacts posed by climate change since the dawn of the 21st century. To support climate risk assessment in comprehensive transport systems, we developed a Climate Change Risk Indicator (CCRI) framework and applied it to the case of the British transport network. Focusing on a multi-modal transport system, this offers researchers and practitioners an invaluable overview of climate adaptation research with the latest tendency and empirical insights. Meanwhile, the developed CCRI framework elaborates a referable tool that enables decision-makers to employ objective data to realise quantitative risk analysis for rational transport adaptation planning.

Dynamic evolution of green total factor productivity growth of China’s coastal ports

ABSTRACT As an important part of the comprehensive transportation system, ports play an important role in economic development. In the context of the ‘3060 double carbon’ target, the high-quality development (HQD) of ports is receiving attention from many parties. The aim of this paper is to examine the dynamic evolution of HQD in China’s coastal ports from the perspective of green total factor productivity (GTFP). Firstly, the calculation standards of undesirable outputs are given, and integrated environmental dumping indicator is calculated by the combination weight calculation model based on game theory. Then, the super-efficiency DEA-GML (Data Envelopment Analysis-Data Envelopment Analysis-Global Malmquist-Luenberger) index model based on directional distance function (DDF) is used to measure the GTFP growth of ports. Furthermore, the dynamic evolution of GTFP growth of ports is explored using the kernel density estimation. The findings show that the GTFP growth of coastal ports has continued to improve during the examined period. However, there is the problem that port construction inputs cannot bring effective outputs, and there is a bifurcation that tends to stabilize within coastal ports. Finally, targeted policy implications are given to promote HQD of ports.

How much behaviour change is required for the investment in cycling infrastructure to be sustainable? A break-even analysis.

Active travel has gained traction among policy makers as a promising solution to physical inactivity. Returns on active travel investments, including cycling infrastructure, crucially rely on resulting improvements in population behaviours. Estimating the expected economic value that an additional regular cyclist will generate and being able to identify the behaviour change required at the population level to offset the intervention costs is important to inform future investment decisions. The WHO's Health Economic Assessment Tool was employed to conduct a break-even analysis. A case study methodology was used which focused on a real-world construction project of a separated cycleway in the UK. The economic assessment considered physical activity benefits, air pollution, crash risk and carbon emissions in monetary terms. An iterative computational approach was applied to identify the behaviour change (cycling) requirements, and corresponding benefits valued using international dollars, to break even on the investment costs. Sensitivity analyses were conducted to assess robustness of the base-case results. Over a ten-year time horizon, an additional regular cyclist (i.e., someone cycling most days of the week) was found to generate $798 (₤533) per annum (international dollars). An additional 267 regular cyclists per km were required to break even on the construction of the new separated cycleway. Estimates were particularly sensitive to variations to age, cycling volume and evaluation time horizon. Policymakers planning to invest in cycling infrastructure should consider using these reproducible, order-of-magnitude estimates to complement the more comprehensive transport appraisal and budget allocation processes. This would ensure that, when considering its health-related economic benefits, the investment is justifiable on economic sustainability grounds.

Identify Important Cities in the Belt and Road Comprehensive Traffic Network

The Belt and Road has developed rapidly in recent years. Constructing a comprehensive traffic network is conducive to promoting the development of the the Belt and Road. To optimize the layout of the Belt and Road comprehensive traffic network, this paper identifies important cities. First, a weighted super adjacency matrix is defined, which includes sea, air, railway transportation and trans-shipment transportation between these transportation modes. With this matrix, the Belt and Road comprehensive traffic network (B&RCTN) is constructed. To identify important node cities, this paper proposes a method to calculate multi-layer centrality which considers inter-layer relationships. With the results of the above four centrality indexes, the Entropy Weight TOPSIS is used to synthesize the evaluation of the four indexes. Finally, the multi-layer comprehensive centrality rank of node cities is obtained. Result shows that there are 72 important cities in B&RCTN. These important cities are mainly distributed in the east and west of Eurasia. Eastern cities are located in East Asia and Southeast Asia, including 36 cities such as Singapore, Shanghai, Guangzhou, Shenzhen and Hong Kong. Western cities are concentrated in West Asia, Western Europe and North Africa along the Mediterranean coast, including 31 cities such as Istanbul, Dubai, Vienna, Trieste and Koper. There are few important cities in central Eurasia, except Almaty in Central Asia and Colombo in South Asia. In addition, important cities also include Moscow in Eastern Europe, Lagos and Lome in West Africa. Finally, based on the distribution of important cities, this paper puts forward some suggestions on the development of the Belt and Road comprehensive transportation.

Calculation example of full cycle carbon emission of super deep foundation pit and carbon reduction measures

The determination of carbon emission from foundation pit engineering is a tough and complex project owing to its characteristics including large material consumption, short use time, difficult recycling and no operation stage. To overcome these limitations, the calculation boundary and calculation method for carbon emission of foundation pit project are defined in this paper, which is successfully applied in the carbon emission analysis of the actual engineering project, i.e. the construction of large-scale foundation pit of Kunming comprehensive transportation international hub. All the carbon emissions coresponding to four working stages including building materials production, building materials transportation, construction and demolition were calculated and anatomized. The results revealed that the content of CO2 released in the stage of building materials production accounts for 89.3% of the total carbon emission, which means the amount of building materials consumed in the engineering project is the crucial factor to control the carbon emission. Besides, two kinds of carbon reduction measures, i.e. optimization design of support scheme and recycling waste materials of internal support demolition, were explored by analyzing the proportion and average value of carbon emission from different sub project of the support structure. A pronounced effect of carbon reduction was achieved. Furthermore, both a fast calculation method of carbon emission factor of unit work volume and general carbon reduction measures are proposed in this paper, which could provide a reference and new viewpoint for the engineers and designers to calculate and analyze the carbon emission and to take effective carbon reduction measures.

Feeder Bus Timetabling Optimization for High-Speed Railway Station with Uneven Departure Interval

This paper proposes a bus timetable with uneven departure interval, which is mainly used to optimize the bus timetable at high-speed railway stations. The railway comprehensive transportation hub is an important node for the connection between the internal and external transportation of the city. Efficient transfer efficiency can not only improve the travel satisfaction of passengers, but also enable public transport enterprises to retain passenger flow in the competition with rail enterprises. Therefore, this paper analyzes the travel time distribution law of railway passenger transfer to public transport, constructs a timetable optimization model that adapts to the passenger flow law, and uses genetic algorithm to solve it. The optimization results show that, without changing the departure frequency, the waiting time of passengers in peak hours using the uneven departure interval mode is reduced by 29.6%, and the waiting time in average peak hours is reduced by 16.2%. If the departure frequency is changed, the waiting time of passengers in the uneven departure interval mode will also be shorter than that in the equal time departure mode.

Measurement Method of Comprehensive Transportation Development Quality Based on Transportation Efficiency

Transportation is the forerunner of economic and social development. Therefore, the high-quality development of comprehensive transportation is of great significance to ensure overall economic and social progress and the smooth implementation of major national strategies. The essence of high-quality development in transportation is to realize the optimal allocation of transportation resources. This study handles two aspects. First, the factors that reflect the quality of comprehensive transportation development are defined and analyzed, and an evaluation system is proposed to build China’s comprehensive transportation development quality with transportation efficiency as the core is proposed, taking into account transportation infrastructure and transportation scale. Second, the static comprehensive evaluation value is calculated by the entropy weight method, and then the incentive control model is constructed by introducing incentive factors to achieve a dynamic comprehensive evaluation of comprehensive transportation development. The research results not only propose new indicators but also evaluate different modes of transportation within the same dimension. The results show that the quality of comprehensive transportation development in China is generally on the rise, but there are obvious regional differences. The proposed model is derived from evaluation cases in transportation-related fields and has not yet been applied in the transportation field. It can help understand the development status of the industry and assist in policy formulation.

Goal-oriented Urban Integrated Transportation Planning under the Concept of Green Mobility

With the development of urban motorization, urban traffic congestion and traffic pollution problems are becoming more and more serious, and the new era of "double carbon" strategic goals have also made important requirements for the transportation sector. The traditional integrated transportation planning has the limitation of being established only to meet the transportation demand, and it also takes less account of the importance of sustainable development. Therefore, this paper reflects on the traditional comprehensive transportation planning from the perspective of the "double carbon" strategic goal, and identifies the problems, combines the current characteristics that there are many green travel modes in the city but not in an orderly way, builds a green travel system in the comprehensive urban transportation planning, integrates the green travel concept into the urban development, and creates a green travel transportation planning system in the urban area. The research results are in line with the requirements of the "double carbon" strategy and the sustainable development of resources, environment and transportation. The research results of this study are in line with the realistic needs and have certain theoretical reference value and practical guidance for urban transportation managers in terms of theory, methodology and practical application.

Planning of Transportation Infrastructure Networks for Sustainable Development with Case Studies in Chabahar

This article addresses the problem of increasing transport services that intercontinental corridors demand from the urban infrastructure networks along their routes. Yet, attention has not been paid to the coordination between the transportation potentials of a city infrastructure network located on the path of an intercontinental corridor and the sustainable application of the corridor itself. This article discusses solving this problem by increasing the transportation capacities of the cities on the path of the corridor. With field studies in Chabahar, we observe the situation of its transportation infrastructure network to discover shortcomings and suggest required changes. This paper recommends the necessary changes and improvements in the urban transportation system of Chabahar to have a sustainable intercontinental corridor and an effective urban infrastructure network simultaneously. The research methods used include observation of traffic flow and behavior in travel origins, destinations, and paths in Chabahar. Then, this study builds a mathematical model with a graph technique to calculate the traffic capacities on the nodes and streets and determine places that require changes. Analyses show that 13,420 cars enter just the center of Chabahar city due to the increasing pressure of the Chabahar–Milak corridor. This paper recommends a multi-modal transportation system with an urban public transport network. It also suggests physical and geometric corrections in sight distances and longitudinal curves of streets, sidewalks, and squares. We find urban transportation failures in the city and present a comprehensive transportation plan for its improvement. This model is applicable in all cities on the route of corridors and assists their sustainable function and urban transport system simultaneously.

Evaluation of Railway Transportation Performance Based on CRITIC-Relative Entropy Method in China

Railway transportation affects the overall transportation process and integrated sustainable development. Evaluation of the railway transportation performance is of great significance for building an efficient and comprehensive railway transportation system. The research establishes a methodology to evaluate railway transportation performance in China. Firstly, the research determines the indexes for evaluation of railway transportation performance, including railway safety, infrastructure, equipment, operation efficiency, and green development. Second, the weight of each index is calculated by using criteria importance through the intercriteria correlation method (CRITIC). Third, the railway transportation performance is assessed based on multi-criteria decision-making (MCDM), by applying the CRITIC-relative entropy method. Finally, the empirical analysis shows that, in 2018, the railway transportation performance is underdeveloped in almost half of China’s railway bureaus and that there are obvious differences between railway bureaus in the east and west. The evaluation of railway transportation performance could be used to improve the sustainable ability of railway transportation in China.