Conventional Bus Research Articles

A Study on the Decay Model of Multi-Block Taxi Travel Demand under the Influence of Major Urban Public Health Events.

A sudden major public health event is likely to have a negative impact on public transport travel for residents, with public travel modes such as the metro and conventional buses experiencing varying degrees of decline in patronage. As a complement to public transport, taxi travel will suffer the same impact. Land use and population density among various functional blocks in a city are different, and therefore their changing rates in taxi travel demand are varied. This paper reveals the taxi travel demand correlations between urban blocks and then constructs a taxi travel demand decay model based on the Dynamic Input-Output Inoperability Model (DIIM) to simulate the decay degree of taxi travel demand in each block. When a major public health event occurs, the residential panic levels in different functional blocks may vary. It results in variable changing speeds of residential travel demand in each block. Based on this assumption, we use the intensity of travel demand as a correlation strength factor between blocks, and equate it with the technical coefficient in the DIIM model. We also define other variables to serve in model construction. These variables include the decay degree of travel demand intensity, residential travel willingness, coefficient of travel demand decay, derivative coefficient of travel demand interdependency, and demand perturbation coefficient. Lastly, we select a central area of Ningbo as the study area, and use taxi travel data in Ningbo during the COVID-19 pandemic of 2020 as input, simulate taxi travel demand dynamics, and analyze the accuracy and sensitivity of the model parameters. The relative errors between the five types of blocks and the actual decay of travel demand intensity are 8.3%, 3.8%, 8.7%, 5.5%, and 5.3%, respectively, which can basically match the actual situation, proving the validity of the model. The results of the study reveal the pattern of taxi travel demand decay among various blocks after major public health events. It provides methodological reference for decision makers to understand the development trend of multi-block taxi travel demand, so as to help form effective emergency plans for different blocks.

Potential Analysis for a New Vehicle Class in the Use Case of Ride-Pooling: How New Model Developments Could Satisfy Customers and Mobility Makers

Due to changes in mobility and the emergence of new services, it is becoming necessary to establish new vehicle classes between conventional buses and privately owned vehicles. New mobility scenarios need concrete specifications to develop the most user-centered shuttle buses. As a result, we are looking for the requirements and needs of operators and customers. Initially, we want to determine the status quo, as there is no preliminary work in this regard. During the course of extensive literature research, expert interviews, and follow-up workshops, the respective solution space was highlighted and narrowed down. Services such as ride-pooling require adapted vehicle concepts to ensure optimal implementation of their offer. Due to its optimized processes, the automotive industry depends on producing vehicles in a certain quantity and manner. Faster changes and extensive experiments are not possible with the current production approach. Purpose-built vehicle concepts can make mobility services more attractive to customers while facilitating business operations. For instance, potential improvements can be identified in the seating concept.

Evaluation of TOD rail station connection design based on analytic hierarchy process and cloud model

It is necessary to carry out an integrated connection design for the rail station area to promote the development of the transit-oriented development (TOD) mode. There is lack of an evaluation index system that comprehensively considers the characteristics of TOD. Based on the characteristics of TOD mode and passenger transfer satisfaction, we propose an evaluation index system for the design of the connections between TOD rail stations and each of the three transportation modes including pedestrians, conventional buses and non-motorized vehicles, respectively. We formulate the grading standards for quantitative and qualitative indicators through literature research and questionnaire survey, respectively. In order to obtain relatively objective and comprehensive evaluation results, we propose an evaluation method combining analytic hierarchy process (AHP) and cloud model, which is superior to single evaluation methods. Finally, Nanjing Xinjiekou rail station is selected as a case for the application of indexes and the evaluation method. The evaluation results about the connection levels of the three transportation modes are medium, good, and medium, which basically conform to the characteristics of central commercial stations.

Stability Improvement of Onboard HVdc Grid and Engine Using an Advanced Power Generation Center for the More-Electric Aircraft

In the high-power settings of engine, such as maximum take-off, more power should be extracted from the high-pressure spool (HPS) than the low-pressure spool (LPS) to avoid the overspeed and potential instability of the HPS. However, as revealed in this paper, extracting more power from the HPS will degrade the onboard HVDC grid stability for the conventional single dc bus power generation center. To address this conflict, in this paper, an advanced power generation center (APGC) incorporating an extra back-to-back (BTB) converter is introduced to improve the stability for both engine and HVDC grid. The BTB converter connects the HP power generation channel and the LP channel, providing an additional power flow path between the HP channel and LP channel. A transfer function-based impedance model and a state-space model of the HVDC grid are proposed to study the HVDC grid stability. The analytical findings of the HVDC grid stability and stability improvement using the APGC architecture have been verified through simulation and experimental results.

Optimization for Feeder Bus Route Model Design with Station Transfer

To fully take the advantages of conventional bus and subway, and to maximize the overall feeder efficiency of the public transport system, the topic of feeder bus route optimization is studied in this paper. Considering the origin destination demand of passenger flow between subway stations and bus stations and transfer characteristics, the objective function is established with the minimum sum of bus operation cost and passenger travel cost. Taking into account the integrity of the feeder bus route, the rationality of the route, the route capacity and the station transfer factors, the constraints of the optimization model are constructed. Based on the idea of the genetic algorithm, the solution algorithm of the optimization model is developed. The genetic algorithm and enumeration algorithm are used to solve the optimization of the feeder bus route in this case, and the accuracy and efficiency of the solution are analyzed. The influence of the number of feeder bus routes on the system in the case network is compared and discussed. We compare and analyze the differences between the original bus network and the feeder bus network in terms of bus operation cost, passenger flow demand and total passenger travel cost. The research shows that the model and algorithm can find the approximate optimal solution of the feeder bus network scheme related to the subway through fewer iterations. The number of routes in the model has little impact on the whole feeder system, and the optimization scheme using five routes is effective and reasonable in this paper. Compared with the existing bus network, the optimization scheme has obvious advantages in improving the passenger-carrying rate, reducing the per capita travel cost and improving the overall operation efficiency of the system.

Development and analysis of new pneumatic based powering options for transit buses: A comparative assessment

Carbon dioxide reduction has been the central focus of current climate change public policy and largely determines procurement of next generation ‘clean’ transit buses. Development of alternative nature-friendly systems for clean transportation is critical in the transition of the sector from conventional fossil fuel-based powertrains. The current study undertakes the design and analysis of a newly-developed hybrid pneumatic powertrain concept for fourty-foot public transit buses using liquid nitrogen and compressed natural gas as a secondary fuel. Various fuel types for system hybridization are investigated comparatively in terms of fuel economy and well-to-wheel carbon dioxide emission ratios. A pure pneumatic configuration is also considered as a base case and discussed accordingly. The performance of the proposed system is evaluated through parametric studies by considering primary design and operational parameters. In similar operational conditions, the performance of a conventional diesel bus, a plug-in hybrid electric bus, a battery-electric bus and a hydrogen fuel cell electric bus is considered in the further comparative assessment of the proposed system. From a well-to-wheel point of view, the emission ratio of the developed hybrid pneumatic system is evaluated at 0.1452 kg carbon dioxide equivalent per kilometer of city driving, which corresponds to a 95% emission reduction compared to conventional diesel buses. The present study results indicate that a hybrid pneumatic configuration carries significant potential for a green transition in the public transit sector. Furthermore, eliminating the need for charging infrastructure, grid upgrading and additional infrastructure capacity, the system can be assembled with readily available off-the-shelf components.

Analyzing Rail Traffic Diversion Based on Machine Learning Technique considering Transportation Security

Based on a stated preference survey, we comprehensively analyze the travel psychology of residents and the advantages and disadvantages of rail transit and conventional buses, travel time, travel cost, travel security, and vehicle comfort and investigate the relationship between the relevant influencing factors and the transition probability from rail transit to buses. A stochastic utility theory is introduced to describe the transfer behavior pertaining to travel modes, and a binary Logit model for diversion transfer is constructed. The decision tree is also used to predict the diversion transfer. Then, based on the large amount of travel willingness data obtained through the stated preference survey, a maximum likelihood estimation method is used to calibrate the parameters of the binary Logit model. The performance of the binary Logit proves to be better than that of the decision tree. Results show that the travel time most notably affects the passenger flow transfer, followed by the vehicle comfort. Finally, Guangzhou Rail Transit Line 3 is considered an example, and the diversion route planning and design are performed according to the constructed diversion transfer probability model to verify the effectiveness and practicability of the model. The research provides an effective theoretical basis and technical reference for other cities to perform rail traffic diversion planning. Based on these results, the following suggestions can be made: (1) the organization of public transportation routes, delivery volume, and travel speed outside should be improved; (2) undertaking combined operation of bus and rail transportation and integrated development is preferred; (3) the transportation management should focus on the comprehensive function development and hardware support of public transportation stations. The convenience and comfort of rail transit are closely related to the facilities and functions of the stations and their connections, which should be highly valued.

Sistem Informasi Sistem Informasi Penyewaan Bus Pariwisata Berbasis Web Pada PT Asli Prima Inti Karya

The existence of tourism facilities and infrastructure are elements to facilitate the process of tourism activities. With the facilities and infrastructure, it is hoped that tourism activities can run smoothly. Among the facilities in tourism activities are transportation/tour buses, travel operators, travel agents, restaurants, hotels/inns, tourist attractions, and tourist attractions. PT Asli Prima Inti Karya is a company engaged in tourism bus rental services, located in Pandeglang Regency, precisely in Labuan, Banten province. PT Asli Prima Inti Karya organizes several tour package and travel agency activities. The conventional bus rental system did not initially cause problems in terms of service. Along with the increasing demand for rental, it takes a complete service so that customers can be served well. The author analyzes the problem and makes a bus rental application design as a solution to the problems in serving customers who will rent buses. The application design uses UML, and uses the Sublime Text 3 programming language, PHP, XAMPP Version 3.2.4, and the database used is MySQL. The results of the application test show that the existence of this information system can make it easier for tenants to carry out the bus rental process.

Exhaust Emissions from a Hybrid City Bus Fuelled by Conventional and Oxygenated Fuel

City buses are one of the main means of public transport in cities. As they move in a limited and densely populated area and are intensively exploited, it is particularly important that they are environmentally friendly. There are many ways to reduce emissions from city buses, including the use of hybrid propulsion. Another way is to use low-emission fuels. This article presents the results of the emission tests of an 18 m articulated city bus with a serial hybrid drive fuelled comparatively by conventional diesel fuel and oxygenated fuel containing 10% v/v of triethylene glycol dimethyl ether (TEGDME). The emission tests were carried out during the actual operation of the bus on a route in Poznań (Poland) and over the SORT cycles. The obtained test results were compared also with the results obtained for a conventional bus. The reduction in emissions of some exhaust components was found when the hybrid bus was fuelled with oxygenated fuel during its actual operation on the bus route. There was a reduction in CO emissions by ~50% and NOx emissions by ~10%. Almost identical levels of PM and HC emissions and smoke opacity were observed for both fuels. In the SORT cycles, the differences in the emissions obtained for both types of fuel were small. In general, for the hybrid bus, a lower influence of oxygenated fuel on emissions was recorded than for the conventional bus.

Parameter Matching Methods for Li Battery–Supercapacitor Hybrid Energy Storage Systems in Electric Buses

The parameter matching of composite energy storage systems will affect the realization of control strategy. In this study, the effective energy and power utilizations of an energy storage source were defined. With the miniaturization of a composite energy storage system as the optimization goal, the linear programming simplex method was employed to obtain the optimized masses of Li batteries and supercapacitors under the constraints of maximum speed, climbing gradient, acceleration time and cost-effectiveness. As the module numbers shall be integers, the matching results were modified in combination with the graphical method. Owing to the influences of parameter matching schemes on the overall performance and battery life, the critical points of constraints were analyzed and the most appropriate matching numerical points of the composite energy storage system were identified. Simulation and experimental analysis were conducted under practical urban road conditions in China. The results show that the proposed matching method delivers accurate results. Compared with conventional electric buses, the mileage and overall performance of the prototype bus are improved.

Research on Route Deviation Transit Operation Scheduling—A Case Study in Suburb No. 5 Road of Harbin

Route deviation transit is a flexible “door-to-door” service method that combines the efficiency of conventional public transport modes and the flexibility of demand response modes, meeting the travel needs of people with low travel density and special groups. In this paper, the minimum value of the sum of vehicle operating cost and passenger travel cost was the optimal goal, and the RDT multi-vehicle operation scheduling model was constructed. Taking the available relaxation time as the control parameter of the RDT system and considering the insertion process of the random travel demand of the passengers during the operation process, we used a heuristic search algorithm to solve the scheduling model. This paper took Suburb No. 5 Road of Harbin as an example, using MATLAB to simulate the RDT operation scheduling model to verify the stability and feasibility of the RDT system under different demands. The results showed that under different demand conditions, the system indicators such as passenger travel time, waiting time, and vehicle mileage in the RDT system fluctuated very little, and the system performance was relatively stable. Under the same demand conditions, the per capita cost of the RDT system was 5.9% to 10.8% less than that of the conventional bus system. When the demand ρ is 20~40 person/hour, the RDT system is more effective than the conventional bus for the 5 bus in the suburbs of Harbin.

Evaluation of travel speed of conventional buses and bus rapid transit service in Ahmedabad city, India using geo-informatics

• GPS data logged by transit vehicles was used to determine travel speed. • Assessed spatio-temporal variability in travel speed of conventional buses and BRTS. • Identified congestion hot spots using Getis-Ord G i * statistics. • BRTS in Ahmedabad city was found 4 km/h faster than the conventional buses. • Travel Speed of BRTS declined to 13 km/h during peak-hours in inner city. Bus Rapid Transit Service (BRTS) attempts to overcome the limitations of conventional bus service with lane separation and higher operational frequency. The policy-makers are frequently required to quantitatively evaluate the improvement in quality of transportation offered by BRTS with respect to that of conventional buses to not only expand the network in newer areas within the city, but also to implement the same in other similar cities. This paper demonstrates an approach based on the Global Positioning Systems (GPS) data logged by transit vehicles in assessing the performance of conventional buses and BRTS in Ahmedabad city, India. The link travel speed derived from GPS data provides an insight into the spatio-temporal variability in conventional buses and BRTS. The congestion hot spots indicating high and low values of travel speed in conventional buses and BRTS were identified using the hot spot analysis (Getis-Ord G i * statistics). The study shows that the BRTS network did provide higher travel speed at lower variability over conventional buses in the study area. However, BRTS provided no improvement in travel speed in the densely populated inner city regions during peak hours, offering little advantage of lane separation. The study also shows the utility of voluminous GPS data logged by transit vehicles that is otherwise lying dormant with transit operators for identifying traffic hot spots within the city.

Efficiency of Connected Semi-Autonomous Platooning Bus Services in High-Demand Transit Corridors

The paper investigates the efficiency of serving high demand transit corridors with connected semi-autonomous bus platoons in both bus and BRT services. Platooning facilitates higher capacity than conventional buses by forming virtual long buses out of multiple smaller vehicles, which may be particularly relevant in scenarios with large demand variations between peak and off-peak hours. The problem is formulated as a constrained optimization problem to minimize total system cost, which includes waiting cost, access cost, riding cost, operating cost and capital cost. For a single period with fixed demand, both analytical solutions and numerical examples are provided. Sensitivity analysis is carried out with regard to demand levels and capacity upper bound. The problem is generalized to a two-period problem considering peak and off-peak demand. Numerical results are provided with sensitivity analysis regarding demand level and ratio of peak/off-peak demand. Furthermore, the impact of a lower bound on service headway is investigated. The result shows that semi-autonomous vehicle platooning is competitive in medium and high-demand scenarios, with the potential of reduced user costs and operating costs at the expense of additional rolling stock costs. Minimum headway constraint, restricted vehicle size, and higher demand ratio all make semi-autonomous platooning more advantageous.

Topology of a Three-Port Converter for High-Altitude Platforms

Three-port converter (TPC) with non-regulated bus cannot meet the voltage stability demands of high-altitude platforms (HAPs) during daytime operations. In contrast, full-regulated bus TPC is complex in topology and inferior in power density, although it can maintain voltage stability across whole day operations. Therefore, semi-regulated bus TPCs are more suitable for this scenario, which can not only maintain voltage stability during daytime operations, but also have simple topology. However, conventional semi-regulated bus structure converts the power twice, leading to lower efficiency and power density. In order to overcome this problem, the paper proposes a novel semi-regulated bus TPC that can be used on high-altitude platforms. The topology only has one conversion between the ports. It regulates the bus voltage during the day and prevents the loss of diode during the night by directly discharging through the MOSFET and achieving high efficiency. The paper adopts GaN devices to elevate the working frequency to further improve the power density, and conduct a theoretical analysis for all working modes and provide key equations. The closed-loop transfer function of the system is deduced for stability analysis. The results show that the proposed topology has high efficiency and power density.

Trusted Execution Environment Hardware by Isolated Heterogeneous Architecture for Key Scheduling

A Trusted Execution Environment (TEE) sets a platform to secure applications based on the Chain-of-Trust (CoT). The starting point of the CoT is called the Root-of-Trust (RoT). However, the RoT implementation often relies on obscurity and provides little flexibility when generating keys to the system. In this paper, a TEE System-on-a-Chip (SoC) architecture is proposed based on a heterogeneous design by combining 64-bit Linux-capable processors with a 32-bit Micro-Controller Unit (MCU). The TEE is built on the 64-bit cores, while the 32-bit MCU takes care of sensitive data and activities. The MCU is isolated from the TEE side by an Isolated Bus (IBus) that sits above the conventional System Bus (SBus). Besides the 32-bit processor, the isolated sub-system contains a Random Access Memory (RAM), a Read-Only Memory (ROM) for storing the boot program, and another ROM for storing root keys. For cryptography accelerators, we have 512-bit Secure Hashing Algorithm 3 (SHA3-512), 128/256-bit Advanced Encryption Standard (AES-128/256), Ed25519, and True Random Number Generator (TRNG) attached to the Peripheral Bus (PBus). Additionally, besides the public channel, the TRNG module also has a private channel that goes directly to the IBus. With RoT implemented inside the isolated sub-system, the RoT is inaccessible from the TEE side after boot. Furthermore, the hidden MCU’s secure boot program makes the key generation flexible and could be updated for many security schemes. To summarize, the proposed design features a flexible and secure boot procedure with complete isolation from the TEE domain. Moreover, exclusive secure storage for the root key and cryptographic accelerators are available for the boot process. The implementation was tested on a Virtex-7 XC7VX485T Field-Programmable-Gate-Array (FPGA). It was also synthesized in a Very Large-Scale Integrated (VLSI) circuit with the ROHM-180nm process library.

Implementation of Power Balance Control Scheme for a Cascaded Matrix-Based Dual-Active-Bridge (CMB-DAB) MVAC-LVDC Converter

Though the merits of matrix-based dual-active-bridge (MB-DAB) ac–dc converter as a submodule for grid-connected multilevel medium-voltage ac (MVac)–low-voltage dc (LVdc) conversion have been presented in recent literature, its operational challenges in the cascaded configuration have not been explored. The objective of this article is to present the inevitable challenge of unequal power routing through the submodules of cascaded matrix-based dual-active-bridge (CMB-DAB) and its mitigation. The detailed and simplified small-signal model of the CMB-DAB converter along with the proposed power balance control (PBC) strategy required to eliminate the power imbalance issue are explained comprehensively. The simulation results for a 3-cell 52.65-kVA CMB-DAB converter along with scaled-down 5.85 kVA experimental results are presented, to demonstrate the unavoidable power imbalance issue and the proposed PBC strategy as a mitigation technique. The proposed scheme is observed to perform seamlessly with the conventional LVdc bus voltage control and remediate power-routing imbalance issue during the steady-state, load-change and hot plug-in/hot plug-out operations.

Economic evaluation of autonomous passenger transportation services: a systematic review and meta-analysis of simulation studies

In order to prepare for their deployment, mobility simulations have been used since the mid-2010s to investigate the effects of Autonomous Vehicles (AV) services. The aim of this study is to provide a review of which impacts were considered in simulation studies, to what extent, and for which results, with an emphasis on economic impacts. Taking cost-benefit analysis (CBA) as a reference framework for the economic evaluation of mobility services, we first establish a list of standard impact indicators in CBA studies. We carry out a descriptive statistical analysis to investigate the use of these indicators, completed by a meta-analysis for the indicators that received sufficient coverage from the literature. The results show evidence of strong use of performance and operational indicators in the simulation literature, but also expose a lack of in-depth analysis concerning environmental and social indicators. With regard to the intensity of impacts, the introduction of autonomous taxis should increase vehicle- kilometers traveled (VKT) by +23% and travel time by +17% compared to conventional private cars. At the same time, it could help to cut 17% of the present fleet size. This performance could be improved if autonomous taxis were shared, limiting the increase of VKT to +6% at the cost of only slightly longer travel times (+20% instead of +17%), while also increasing fleet reduction by up to -55%. Compared to conventional bus or train lines, these on-demand AV services could permit travel time to be reduced by half and could also reduce financial operating costs. On the other hand, they would increase fleet size and VKT by three to seven times their initial values. AV impacts could vary considerably depending on the socioeconomic landscape of the implementation area. Our findings call for evaluating AV services from a wider perspective than operational and financial prisms alone as is currently the case, such as using cost-benefit analysis.JEL classification: H43, L92, L91.

Impactar Tool: Valuing Air Quality Health Impacts of Urban Bus Fleet Changes in Brazil (2022)

In Brazil, where the transport sector is one of the biggest contributors to air pollution in cities, replacing conventional buses with electric vehicles can save lives and positively impact the economy. This is what ImpactAr tool, a technical note and a valuation model, demonstrates. Developed in partnership with the Children’s Investment Fund Foundation (CIFF), ImpactAr provides the magnitude of the variations on the number of fatalities and hospitalizations and the consequent economic and welfare costs related to changes in air pollution levels caused by modifications in the Brazilian urban bus fleets. The methodology can be applied by any city, sector operators, academics and researchers. For São Paulo, Rio de Janeiro, Belo Horizonte and Niterói, spreadsheets are already set up with data for environmental, epidemiological and economic projections. By making the implicit impacts on health and well-being of air pollution visible, ImpactAr can encourage cities to initiate or accelerate the transition from public transport to green fleets.

Trendovi i perspektive primene autobusa na električni pogon u gradovima Evrope i sveta

The electric bus (E-bus) is a new concept of environmentally friendly and energy-efficient bus subsystem of public urban transport, which is increasingly present in many cities around the world. The introduction of this type of bus has a steady upward trend and is a major alternative to conventional buses. The paper gives a brief chronology of the most important events related to the application and introduction of electric buses around the world, the current state of the number of vehicles in operation, an overview of the electric bus market, and future directions of further development and implementation of this new concept in public transport, with a special emphasis on Europe.

Air Quality and Active Transportation Modes: A Spatiotemporal Concurrence Analysis in Guadalajara, Mexico

The protection of pedestrians, cyclists, and public transportation passengers from environmental pollution is a global concern. This study fills the gap in the existing knowledge of temporal exposure to air pollution in Latin American metropolises. The paper proposes a methodology addressing the relationship between two objects of study, i.e., the users of active modes of transport and air quality. This new methodology assesses the spatiotemporal concurrence of both objects with statistical analysis of large open-access databases, to promote healthy and sustainable urban mobility. The application of the empirical methodology estimated the number of users of active transportation modes exposed to poor air quality episodes in the Guadalajara metropolitan area (Mexico) in 2019. The study considered two pollutants, ozone (O3) and particulate matter (PM10), and two active modes, cycling and bus rapid transit (BRT). Spatiotemporal analyses were carried out with geographic information systems, as well as with numeric computing platforms. First, big data were used to count the number of users for each mode within the area of influence of the air quality monitoring stations. Second, the number of air pollution episodes was obtained using the air quality index proposed by the Environmental Protection Agency (USA) on an hourly basis. Third, the spatiotemporal concurrence between air quality episodes and active mode users was calculated. In particular, the air quality monitoring data from the Jalisco Atmospheric Monitoring System were compared to users of the public bicycle share system, known as MiBici, and of a bus rapid transit line, known as Mi Macro Calzada. The results showed that the number of cyclists and BRT passengers exposed to poor air quality episodes was considerable in absolute terms, that is, 208,660 users, while it was marginal when compared to the total number of users exposed to better air quality categories in the study area, who represented only 10%. To apply the results at the metropolitan scale, the spatial distribution of the air quality monitoring system should be improved, as well as the availability of data on pedestrians and conventional bus passengers.