Monash University, Institute of Transport Studies: World Transit Research (WTR)
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Distributed electric bicycle batteries for subway station energy management as a virtual power plant
No full textImproving the energy efficiency of transportation systems is essential for accelerating decarbonization. Integrating regenerative braking energy (RBE) in subway stations is challenging for power systems. The existing multimodal transport of electric bicycles and subways lends subway station energy storage resources to manage the RBE. In this article, we proposed a virtual power plant (VPP) scheme comprising subway stations, electric bicycles, and photovoltaic systems. We developed an optimization model to manage the charging of distributed electric bicycles to integrate the RBE and reduce the total electricity bill of the VPP. We applied the proposed model to Beijing Subway Lines 5 and 13 and investigated the benefits of the VPP scheme and multimodal transport. The results indicate that the VPP can integrate 42% of the RBE and generate a high profit rate
Optimal electric bus scheduling method under hybrid energy supply mode of photovoltaic-energy storage system-power grid
No full textCurrently, the charging energy of electric buses (EBs) primarily relies on the power grid (PG), and the production of the electricity for the power grid still results in carbon emissions. In recent years, a remarkable development has been observed in the photovoltaic (PV) technology. If EBs can be charged using electricity generated from PV, it has great potential to significantly reduce carbon emissions for EB systems at the source. Considering the inherent output power fluctuations from PV source, we propose a hybrid electricity supply mode named “Photovoltaic-Energy Storage System-Power Grid” (PV-ESS-PG). Firstly, considering the characteristics of different electricity supply modes, we introduce charging strategies tailored to different scenarios and formulate a cooperative optimization model for EB dispatching and charging plans. Secondly, we decompose this model into two sub-problems: bus dispatching and charging scheduling. To solve these two sub-problems, we employ the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to obtain the optimization results of bus dispatching plan, charging mode, charging start time, and charging duration. Finally, we validate the proposed method using real-world data of EB operation and PV output power. We further analyze the influences of weather conditions, ESS capacity, and EB rated battery capacity on the optimization results. We find that, compared to the conventional unitary power grid electricity supply mode, the proposed method reduces daily charging costs by 25.48% and carbon emissions by 68.71% of the whole bus route
Car dependency in the urban margins: The influence of perceived accessibility on mode choice
No full textCar dependence is a dimension of transport poverty whose subjective components have been limitedly explored. Research on car dependence highlights the incidence of transport costs, assesses the multidimensional vulnerability of car-dependency and the possibility to access valued opportunities. However, people’s perceptions and their perceived ability to access destinations may better reflect the way they move in car dependent settings. In this paper, we aim to examine what are the determinants of perceived accessibility and to which extent perceived accessibility influences mode choices in such areas. Based on a survey carried out in four peripheral and periurban municipalities in the Metropolitan Region of Santiago de Chile, we examine how subjective perceptions of accessibility contribute to explain modal choice in the outskirts. Results show that perceived accessibility has a negative net impact on the utilities for both car and public transport, which means that a low perceived accessibility increases the likelihood of choosing motorized modes. Moreover, residents from peripheral municipalities tend to perceive a higher accessibility than households from periurban areas, who are excluded from the public transport system. These findings show the importance of providing nearby opportunities and convenient alternatives to limit car dependency, especially in periurban areas
Are Transit-Oriented Development and Travel Characteristics Influencing Residential Dissonance? Analysis From a Developing Country’s Perspective
No full textThe success of transit-oriented development (TOD) could hinge on reduced residential dissonance among the people living in TOD neighborhoods. Understanding the factors that could be associated with residential dissonance would be crucial in different contexts. Therefore, this study focused on exploring the various factors, such as TOD indicators, travel, and socio-demographic characteristics, that could influence the level of dissatisfaction of people living in TODs in Hyderabad, India. An ordered logit model was developed, which used data collected from primary as well as secondary sources. Results showed negative impacts of gender (male) and income on levels of dissatisfaction about neighborhoods, prompting policy interventions to address the disparities in gender and income groups. Further, it outlined the need to fulfill the varying requirements of larger households to reduce the dissonance. The roles of density, horizontal land-use diversity, and proximity to transit are very significant in improving living-satisfaction levels among people in TODs. More findings suggested the need for well-designed and maintained public spaces to address concerns related to safety and security and improve levels of satisfaction with TOD neighborhoods. The study also suggested that travel distances for educational trips, trip frequencies for work and shopping, and the use of private vehicles for work trips have positive influences on residential dissonance. It would be important to look for ways to provide convenient and sustainable alternative modes along with compact and diverse development, even though a longer commute may be acceptable
Correlates of Modal Substitution and Induced Travel of Ridehailing in California
No full textThe availability of ridehailing services, such as Uber and Lyft, affects the way people choose to travel and can enable travel opportunities that were previously suppressed, leading to additional trips. Previous studies have investigated the modal substitution and induced travel caused by ridehailing, yet few have investigated the factors associated with these travel behaviors. Accordingly, this study examines the personal and trip characteristics associated with ridehailing users’ decisions to substitute other modes of travel or conduct new trips by ridehailing. Using detailed survey data collected in three California metropolitan regions from 2018 and 2019, we estimated an error components logit model of ridehailing users’ choice of an alternative travel option if ridehailing services were unavailable. We found that over 50% of ridehailing trips in our sample were replacing more sustainable modes (i.e., public transit, active modes, and carpooling) or were creating new vehicle miles, with a 5.8% rate of induced travel, with public transit being the most frequently substituted mode. Respondents without a household vehicle and who use pooled services were more likely to replace transit. Longer-distance ridehailing trips were less likely to replace walking, biking, or transit trips. Respondents identifying as a racial or ethnic minority or lacking a household vehicle were least likely to cancel a trip were ridehailing unavailable, suggesting their use of ridehailing for essential rather than discretionary purposes. Together, these findings provide valuable insights for policy makers seeking to address the environmental and equity issues associated with ridehailing
Bikeshare–Metrorail Integration in Washington, D.C.: What are the Characteristics of Neighborhoods that Encourage Capital Bikeshare Trips to and from the Metrorail?
No full textBikeshare has gained popularity worldwide and can serve as a first mile/last mile feeder for public transport. In many bikeshare systems, docking stations near a metrorail station are popular trip origins and destinations and bikeshare can help increase the ridership of the metrorail system as well. The goal of this study is to identify the determinants of bikeshare trips between neighborhood stations and bikeshare docking stations near the metrorail in Washington, D.C. For this study, we divided the bikeshare stations in Washington, D.C., into two categories: docking stations near a metrorail station (defined as bikeshare docking stations within a quarter mile radius of metrorail stations) and neighborhood stations (bikeshare docking stations outside the quarter mile radius of metrorail stations). We used two stepwise linear regression models of bikeshare trips between neighborhoods and metrorail stations stratifying the analysis by the determinants of neighborhood docking stations into four categories: socio-demographic conditions, transportation related, land use, and points of interests. In the backward elimination model, expanding the bike trail supply by an additional 100 m was associated with an increase in 70 annual bikeshare trips between a neighborhood station and a docking station near the metrorail. The forward selection model showed that a 1% increase in the poverty rate of the neighborhood stations was associated with 52 fewer annual such bikeshare trips. This study also found that adding bikeshare docking stations near national parks and neighborhoods with higher population density can promote bikeshare that starts/ends near metrorail stations
Spatial effects of carbon pricing on transport equity
No full textThere is an ongoing process that greenhouse gas emissions of transport will be incorporated in the European Emissions Trading System. The cap-and-trade approach will result in substantial price increases for fossil fuels which will affect affordability of the transport systems. Within this paper the regressive effect on car-owning households is described in different area categories of the urban and rural region in Germany. Equal-per-household redistribution of the carbon revenue could reverse the regressive effect into a progressive effect. However, there is substantial variation within the different economic status groups leaving notable shares of households with a very low economic status without a positive net transfer. This share will be lowest in the metropolises of the urban region and highest in small-sized cities/village areas of the urban and rural region. Particularly in the latter area categories, these households may need temporary mobility allowances due to limited abatement options. Despite the environmental bonus, electric car-owning households still belong to groups of higher economic status, and public transport supply is limited, particularly in the small-sized cities/village areas of the urban and rural region
Design of railway transition zones: A novel energy-based criterion
No full textRailway transition zones (RTZs) experience higher rates of degradation compared to open tracks, which leads to increased maintenance costs and reduced availability. Despite existing literature on railway track assessment and maintenance, effective design solutions for RTZs are still limited. Therefore, a robust design criterion is required to develop effective solutions. This paper presents a two-step approach for the formulation of a preliminary-design criterion to delay the onset of processes leading to uneven track geometry in RTZs. Firstly, a systematic analysis of each track component in a RTZ is performed by examining spatial and temporal variations in kinematic responses, stresses and energies using a finite element model of an embankment-bridge transition. Secondly, the study proposes an energy-based criterion to be assessed using a model with linear elastic material behavior and states that an amplification in the total train energy in the proximity of the transition interface is an indicator of increased (and thus non-uniform) degradation in RTZs compared to the open tracks. The correlation between the total strain energy (assessed in the model with linear material behaviour) and the permanent irreversible deformations is demonstrated using a model with non-linear elastoplastic material behavior of the ballast layer. In the end, it is claimed that minimising the magnitude of total strain energy will lead to reduced degradation and a uniform distribution of total strain energy in each trackbed layer along the longitudinal direction of the track will ensure uniformity in the track geometry
Spatial-temporal identification of commuters using trip chain data from non-motorized mode incentive program and public transportation
No full textDistinguishing commuters from non-commuters is important for transportation planning and traffic demand management. A framework to identify commuters using public transit is proposed based on a spatial-temporal clustering algorithm. The framework extracts commute trips by mining spatial-temporal travel patterns depending on whether the travelers\u27 trip chains are complete. The commuting features in terms of travel frequency, time regularity, and spatial regularity are utilized to compare the difference in travel behavior between commuters and non-commuters. The framework is applied to trip data collected from an incentive program implemented by the Metropolitan Transport Commission of Korea. The data records spatial and temporal information on travelers\u27 boarding and alighting points, as well as actual origins and destinations. One trip record constitutes a complete trip chain for travelers who joined the incentive program. The results show that commuters exhibit a higher travel frequency and more regular spatial-temporal travel patterns than non-commuters. It is found that not all commuters travel during morning and evening peaks; some commuters leave work after evening peak. The proposed identification framework based on the spatial-temporal clustering approach is capable of exploiting the inherent spatial-temporal travel patterns of travelers to achieve a reliable identification of commuters
Flood risk assessment of urban metro system using random forest algorithm and triangular fuzzy number based analytical hierarchy process approach
No full textThe metro system is an essential component of urban transportation; however, it is vulnerable to flooding under extreme rainfall. This study proposes a metro flood risk assessment approach by combining urban flood inundation model, random forest algorithm (RF), and triangular fuzzy number based analytic hierarchy process (TFNAHP). The evaluation indicators are selected based on the theory of hazard, exposure, and vulnerability, which are quantified through urban flood inundation model and geographic information system (GIS) technology. To solve the subjectivity of determining indicator weights, the data-driven RF algorithm is applied to identify indicator importance and create fuzzy judgment matrices of AHP. Moreover, the triangular fuzzy number is integrated with AHP to handle uncertain evaluation information. Taking the metro system in Zhengzhou, China as a case study, the flood risk is assessed for both metro line buffer zones and metro stations. The high-risk areas comprise more than 30 % of the study area. The assessment result is consistent with the historical flood condition. Furthermore, the proposed approach is more effective and suitable for metro flood risk assessment than the traditional AHP method. This study offers a new way for metro flood risk assessment and provides support for flood prevention in metro systems