Modeling electric taxis' charging behavior using real-world data

Charging behavior is critical to the development and deployment of electric vehicle (EV) systems, given its impacts in EV adoption, the energy and environmental performance of EVs, potential load change to the electric grid, etc. However, the general characteristics of practical charging behavior have not been well studied. Existing studies are mostly based on travel data from conventional internal combustion engine vehicles, modeled with assumed and simplified charging scenarios. The use of public charging infrastructure is often neglected. Few studies evaluate real-world charging behaviors of EVs currently in operation using public charging stations. To address this gap, this study analyzes the data of 39,372 charging events from 129 unique electric taxis in Shenzhen, China to study the distributions of daily charging frequency, charging start time, and charging duration. The insights we learned from this study are: 1) the daily frequency for a vehicle to visit charging stations is unlikely to exceed five times; 2) the distribution of charging start time have multiple peaks and can be fitted with Gaussian Mixture Models; 3) charging duration is influenced by charging start time; and 4) charging dynamics can be modeled using the distributions of daily charging frequency, charging start time, and charging duration. Results from this study can inform charging behavior modeling for EVs and charging infrastructure development.     

Conditions for electric vehicle taxi: A case study in the Greater Stockholm region

This study investigates the usability of electric vehicles (EVs) in a taxi company in Greater Stockholm, Sweden. By investigating cost and revenue data of both electric and conventional taxi vehicles, as well as by interviewing taxi drivers and carriers, an assessment has been made of the financial and operational implications of using EVs in a company’s taxi fleet. Both the drivers’ and the carriers’ perspectives have been examined. The main findings are that the investigated e-taxis have a similar or lower Total Cost of Ownership and slightly higher profitability than the investigated conventional taxis. For taxi drivers, using e-taxis implies more advanced planning and revenue service time being sacrificed for charging. However, certain customers’ preferences for EVs, as well as benefits such as corporate clients favoring e-taxis and a zero emission priority queuing system at Stockholm’s main international airport (partly) compensate for time devoted to charging. In order to facilitate increased use of e-taxis, more fast charging facilities should become available at strategic locations. Besides that, there are signs that carriers’ lack of information about the opportunities and consequences of shifting towards e-taxis hamper a wider deployment of e-taxis.     

A review of spatial localization methodologies for the electric vehicle charging infrastructure

With view to the high share of the transport sector in total energy consumption, e-mobility should play an important role within the transition of the energy systems. Policymakers in several countries consider electric vehicles (EV) as an alternative to fossil-fueled vehicles. In order to allow for the development of EV, the charging infrastructure has to be set up at locations with high charging potential, identified by means of various criteria such as demand density or trip length. Many methodologies for locating charging stations (CS) have been developed in the last few years. First, this paper presents a broad overview of publications in the domain of CS localization. A classification scheme is proposed regarding modeling theory and empirical application; further on, models are analyzed, distinguishing between users, route or destination centricity of the approaches and outcomes. In a second step, studies in the field of explicit spatial location planning are reviewed in more detail, that is, in terms of their target criteria and the specialization of underlying analytical processes. One divergence of these approaches lies in the varying level of spatial planning, which could be crucial depending on the planning requirements. It is striking that almost all CS locating concepts are proposed for urban areas. Other constraints, such as the lack of extensive empirical EV traffic data for a better understanding of the driving behavior, are identified. This paper provides an overview of the CS models, a classification approach especially considering the problem’s spatial dimension, and derives perspectives for further research.     

Road infrastructure and economic development in the periphery: the case of A55 improvements in North Wales

This paper examines the impact of a major road improvement programme on the economic development of North Wales. The paper identifies the economic impacts of the road on a selection of firms and organisations in North Wales, and provides a modelling framework to examine the static and dynamic effects of road improvements. Road improvements across North Wales are found to be a necessary, but not sufficient, condition for economic development in this peripheral area.     

Exploring the choice of battery electric vehicles in city logistics: A conjoint-based choice analysis

Adoption of electric vehicles by transport companies remains limited although major European cities should reach CO₂-free city logistics by 2030. This paper explores therefore the vehicle choice behaviour of transport companies through a conjoint-based choice analysis.The results showed that the benefits of battery electric vehicles are less valued than their disadvantages. However, a majority of respondents agrees that authorities should encourage the use of battery electric vehicles. Based on the preferences of transporters, we conclude that the most important measures are to develop a larger charging infrastructure and implement financial incentives through subsidies or tax exemption.     

Emissions and exposure costs of electric versus conventional vehicles: A case study in Texas

The emissions and human exposure impacts of electric vehicle (EV) adoption, especially in comparison to conventional gasoline- or diesel-powered engines, depend on numerous factors including geography, electricity generation, and fuel mix. Results of any analysis also vary depending on the nature of data collected and their level of aggregation by time or location. This paper combines several approaches to develop a robust estimate of these impacts specific to the state of Texas by considering marginal emissions by time of day, as well as location of vehicle and power plant emissions. The authors estimate health and other external costs of operating an EV in the state at approximately $62 per year, compared with an average of $136 for a passenger car powered by gasoline.     

How uncertain is the future of electric vehicle market: Results from Monte Carlo simulations using a nested logit model

Plug-in electric vehicles (PEVs) are widely regarded as an important component of the technology portfolio designed to accomplish policy goals in sustainability and energy security. However, the market acceptance of PEVs in the future remains largely uncertain from today's perspective. By integrating a consumer choice model based on nested multinomial logit and Monte Carlo simulation, this study analyzes the uncertainty of PEV market penetration using Monte Carlo simulation. Results suggest that the future market for PEVs is highly uncertain and there is a substantial risk of low penetration in the early and midterm market. Top factors contributing to market share variability are price sensitivities, energy cost, range limitation, and charging availability. The results also illustrate the potential effect of public policies in promoting PEVs through investment in battery technology and infrastructure deployment. Continued improvement of battery technologies and deployment of charging infrastructure alone do not necessarily reduce the spread of market share distributions, but may shift distributions toward right, i.e., increase the probability of having great market success.     

The influence of green practices on supply chain performance: A case study approach

The main objective of this exploratory paper is to investigate the relationships between green practices of supply chain management and supply chain performance. This relationship is investigated in the context of the automotive industry. Five research propositions are suggested and tested with empirical data derived from five case studies taken from the Portuguese automotive supply chain. The data analysis identifies the most important green practices considered by managers, as well as the performance measures that are most appropriate and most widely used as means to evaluate the influence of green practices on supply chain performance. A conceptual model was derived from the data analysis and it can be used to assess the influence of green practices on supply chain performance. This model provides evidence as to which green practices have positive effects on quality, customer satisfaction and efficiency. It also identifies the practices which have negative effects on supply chain performance.     

A study on passengers' airport choice behavior using hybrid choice model: A case study of Seoul metropolitan area,South Korea

Improving explanatory power is significantly important to understand variables that affect attitudes and perceptions in the decision process. This paper estimates not only tangible attributes but also intangible perceptions and attitudes using a hybrid-choice model to study air passengers' flight choice behavior. The empirical study was conducted for the choice behavior of air passengers at Seoul Metropolitan Area, South Korea. The analysis uses a two-level Nested Logit model in order to examine which factors have more effect on passengers’ choice of airport and airline simultaneously by using airport and airline choice attributes. The study also estimated the parameters in the equations relating the latent variable by using Structural Equation Model (SEM). The results indicate that the models with latent variables have improved Goodness-of-Fit when compared to classical discrete choice models and effectively capture psychological factors that affect choice behavior of passengers.     

A study on travelers' transport mode choice behavior using the mixed logit model: A case study of the Seoul-Jeju route

This study is to analyze passengers' choice of the mode of transportation when air transportation is in competition with high speed rail (HSR). The Seoul-Jeju route analyzed as an empirical case study, in which the construction of an undersea tunnel to connect Seoul and Jeju city by HSR has been considered. The study also included two new variables, ‘safety of transportation’ and ‘availability of duty free shopping’ in addition to traditional transport choice variables such as travel time, travel costs and frequency of service to reflect special characteristics of the market. As data gathering tools, SP techniques and mixed logit model, for analytical methodology, were utilized. The authors found that the goodness of fit of the models was improved with new variables. The models also showed that the characteristics of business passengers and leisure passengers in choosing the mode of transportation were different. Business passengers were apt to choose a safety secured mode of transportation regardless of fare while leisure passengers preferred to use duty free shops more than business passengers.     

An integrated approach to modeling the impact of floods on emergency services: A case study of Calgary,Alberta

Floods are becoming more frequent and the magnitude of direct consequences, relating to destruction of critical infrastructure and loss of life, has highlighted the importance of flood management. This study proposes a methodology for quantifying the impact of predicted and historic flood events on emergency services. The approach moves beyond simple flood inundation mapping by accounting for the relationship between flood depth and vehicular speed. A case study is presented for Calgary, Alberta, where the depths of a predicted 100-year flood and a historic 2013 flood event are modeled. The methodology applies geographic information systems to flood depth mapping, utilizing digital elevation models, flood extents, and hydrological data. Flood depths are then assigned to links comprising the road network, where the maximum vehicle speed is calculated as a function of the standing depth of water on a link. The flooded network is used to derive service areas for several types of emergency services (emergency medical services (EMS), fire, and police), following targeted response times. The results locate and quantify the residential and work populations that no longer meet the targeted response times. During both flood scenarios, EMS is found to have the greatest reduction in accessibility, with 23% and 47% of residents and workers, respectively, not served. Fire services are seen to be more resilient with only 3% and 9% of residents and workers, respectively, not served. The results for police services are similar to fire services. However, the former have a greater range of response times, meaning these areas represent those that are completely isolated during both flood events. Overall, the integrated methodology quantifies vulnerable populations on a partially degraded network, the results of which can be used to develop evacuation plans and emergency response strategies.     

A case study: The impact of low-cost carriers on inbound tourism of Saudi Arabia

This study investigates the impact of low-cost carriers (LCCs) on Saudi Arabia's tourism demand. It also provides an understanding of the relationship between air transport development and tourism development in the Gulf region. The Box–Jenkins SARIMA-X models were employed to model and forecast international tourist arrivals to Saudi Arabia, using monthly international tourist arrivals to Saudi Arabia from July 2010 to December 2015. The forecasting models were significantly accurate, with lower values of MAPE, MAP, and RMSE. The findings suggest that an increase in airline capacity, religious travel, and airline competition are associated with the increasing international tourist arrivals to Saudi Arabia. This also indicates that there is a positive relationship between air transport development and tourism development. Further aviation liberalisation in the Gulf region is discussed to give opportunities for the region's LCCs to increase their share of the increasing air travel demand, thereby enhancing tourism development.     

Congestion tolls and parking fees: A comparison of the potential effect on travel behavior

This paper presents a comparison of attitudes towards congestion and parking tolls and explores their effect on travel behavior. The findings indicate that drivers are sensitive mainly to congestion tolls and are willing to change their travel habits to avoid these tolls. The major effect of a congestion toll is the shifting of the time of the journey. High levels of demand elasticity (−1.8 for congestion tolls and −1.2 for parking fees) were found. The readiness to pay parking fees is greater; thus, the effectiveness of congestion tolls in reducing demand is higher during the times the tolls apply.     

The effect of a roundabout corridor's design on selecting the optimal crosswalk location: A multi-objective impact analysis

Crosswalks located at mid-block segment between roundabouts can provide a good balance among delay, carbon dioxide (CO₂) emissions, and relative difference between vehicles and pedestrians speed. However, when considering local pollutant criteria, the optimal crosswalk location may be different to that obtained for CO₂. This paper described a multi-objective analysis of pedestrian crosswalk locations, with the objectives of minimizing delay, emissions, and relative difference between vehicles and pedestrians speed. Accounting for the difference between global (e.g., CO₂) and local pollutants (monoxide carbon, nitrogen oxides, and hydrocarbons) was one the main considerations of this work. Vehicle activity along with traffic and pedestrian flows data at six roundabout corridors in Portugal, one in Spain, and one in the United States were collected and extracted. A simulation environment using VISSIM, Vehicle Specific Power, and Surrogate Safety Assessment Model models was used to evaluate traffic operations along the sites. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was implemented to further search optimal crosswalk locations. The results yielded improvements to both delay and emissions by using site-optimized crosswalks. The findings also revealed that the spacing between intersections widely influenced the optimal crosswalk location along a mid-block section. If the spacing is low (<100 m), the crosswalk location will be approximately in 20%–30% of the spacing length. For spacing values between 140 and 200 m, crosswalks would be located at the midway position. When a specific pollutant criterion was considered, no significant differences were observed among optimal crosswalk data sets.     

Effects of non-aeronautical activities at airports on the public transport access system: A case study of Zurich Airport

Many planning authorities and airports study measures to increase public transport use for airport ground access and egress. At the same time, an increase in real estate development at and around airports is occurring, both due to airports seeking new revenue possibilities and other developers attempting to profit from high value locations. This paper considers non-aeronautical activities at large airports, largely commercial centres and transit hubs, as land uses that have the potential to improve the situation for operating public transport services. In order to assess potential benefits and disadvantages, four research questions are considered: (1) Can the additional travel volume reach levels at which it has a significant impact? (2) To what extent do non-aeronautical activities influence the public transport access system? (3) Is the resulting demand distribution better or worse regarding peaking behaviour? (4) Is there a potential for the resulting overall demand to bring about capacity shortages?A case study is conducted at the airport of Zurich, Switzerland, which finds that non-aeronautical activities in the direct airport vicinity have led to a situation where the operation of public transport services is much more viable due to overall higher passenger numbers and a more even distribution throughout the day. It is concluded that locating non-aeronautical activities at airports can, in addition to providing commercial benefits to developers, lead to a situation where improved public transport services become feasible.     

Modeling the effects of wage premiums on airline competition under asymmetric economies of density: A case study from Brazil

This paper investigates the effects of wage premiums on the competition between Full Service Carriers (FSC) and Low Fare Carriers (LFC) in the airline industry. We study the impact of changes in the labor market and the resulting effects on performance in the product market and examine the role of economies of density. We develop an oligopoly model of airline competition with endogenous wages and simulate increases in labor costs. We apply the model to the case of the most important domestic route of Brazil using airline/route-specific demand and costs data. Our chief contribution relies on the empirical model of asymmetric economies of density for the competing business models. We estimate that LFCs have higher economies of density than FSCs. With the empirical models of demand, costs and wages, we compute the wage-elasticities of price-cost markups. We find that, on account of the higher sensitivity of marginal costs to labor costs of the FSCs, their markups are more affected by wage premium increases than the markups of the LFCs. The results are attenuated by higher economies of density, but amplified by higher price-elasticities of demand and lower economic growth.     

A study of the site selection of a civil airport based on the risk of bird strikes: The case of Dalian,China

Bird strikes are a potential danger to aviation security. The threat of birds to the flight security of civil airplanes is hard to solve if the existence of birds in nature is ignored. An in-depth study on the living habits of birds and the request for a harmonious coexistence between birds and civil airplanes seems to be an effective way to relieve this contradiction. Taking the case of the site selection of the civil airport in Dalian of China, this paper comprehensively analysed the bird strike assessment of various species of birds near the sites of Zhoushuizi Airport and Jinzhou Bay Airport. The assessment of the risk of bird strikes demonstrated that the site of the Jinzhou Bay airport would have a smaller risk of bird strikes, which could greatly reduce collisions between birds and airplanes and promote aviation security. Such results provide a valuable reference for the site selection of the civil airport in Dalian. As bird strikes are a common problem in the field of civil aviation, the analysis and methods in this paper are a needed reference for the planning and land use of civil airports in other cities.