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.     

Optimizing station location and fleet composition for a high-speed rail line

This paper proposes a new strategic planning model for high-speed rail ventures. It is a mixed-integer optimization model that applies to a given line and focuses on two key strategic decisions: station location and fleet composition. Our purpose is to improve on previous station location models by including fleet composition decisions. In the new model, we additionally take into account in an approximate fashion the interrelationships between strategic and subsequent tactical decisions, regarding line planning, train scheduling and fleet assignment issues. The usefulness of the model is demonstrated for a case study involving a planned Lisbon-Oporto high-speed rail line.     

Looking for the obvious: Motorcycle taxi services in Sub-Saharan African cities

Motorcycle taxis (MCT) have been present in many cities of Sub-Saharan Africa for several decades. This paper aims to answer two questions: How can we objectify the massive and lasting development of a “motorcycle taxi model” in the cities of SSA? How does this model function in practice? First, the spread of motorcycle taxis in Sub-Saharan Africa is examined by using an internet-based bibliometric analysis of academic output and local press articles. Second, the functioning of the industry and the informalization rationales at work in the deployment of the motorcycle taxi model are analyzed on the basis of a field study in Lomé, the capital of Togo.The bibliometric analysis of the academic output shows the presence of MCT in 14 countries over a 30 year period, and that of the local press almost doubles the number of countries. It also provides some temporal reference points and suggests some reasons for MCT deployment. Three main features of the functioning of the MCT industry in Lomé are identified: the equivocal attitude of the State, the heterogeneous characteristics of the players, and the strong and multifaceted linkages of MCT with formal activities. The results from this research provide evidence that the development of the motorcycle taxi model in SSA is closely associated with globalization and informalization processes.     

An exploratory empirical analysis of willingness to hire and pay for flying taxis and shared flying car services

A new transportation mode that can simultaneously operate on land and in the air, namely the flying cars, is anticipated to penetrate the automobile fleet between 2020 and 2025. Due to their flexible mobility patterns and automated operational characteristics, flying taxi and shared flying car services are expected to expand the existing shared mobility services (such as Uber, Lyft, and similar services) of the urban transportation network. Despite their forthcoming introduction in the shared mobility market, public perceptions and expectations about these services have not been investigated in travel demand literature. This study aims to provide an exploratory analysis of public willingness to hire and pay for flying taxis and shared flying car services, and to identify the determinants of the willingness to hire and pay for such services. Using data collected from an online survey, individuals' willingness to hire and to pay for flying taxi and shared flying car services are statistically modeled within a correlated grouped random parameters bivariate probit framework. The analysis shows that various socio-demographic characteristics and individuals’ opinions towards the perceived benefits and challenges of flying cars affect public willingness to hire and pay for flying taxi and shared flying car services. Even though the awareness about the operation of flying taxis and shared flying car services is possibly limited in the public sphere, the findings of this study can provide insights into the challenges that policymakers, manufacturing companies, and shared mobility providers will face with the introduction of such flying car services in the transportation networks.     

A traffic engineering model for air taxi services

We propose a single-provider model for on-demand air taxi services. Data from a discrete-event model support a “flow model,” which describes the aggregate flow of passengers and aircraft for an air taxi service provider without specifying event-level operation. Using a set of hypothetical scenarios for air taxi network operation, we evaluate the accuracy of the flow model against the outputs of the discrete-event model. Finally, we illustrate how the flow model can be applied towards the optimal pricing of passenger fares for a single air taxi service provider.     

Analysis of the effect of charging infrastructure design on electric taxi driving profiles: A case study approach on the example of Singapore

Replacing conventional vehicle taxis with electric vehicles would be an efficient measure to reduce greenhouse gas emissions. Due to the limited range and long charging times of current battery electric vehicles, it is of utmost importance to provide sufficient charging facilities. This article analyses the impact of the placement and charging power of charging stations on potential mileage and revenue of electric taxis on the example of Singapore. Therefore, we developed an agent-based electric taxi simulation model to investigate electric taxis’ driving profiles with respect to different vehicle types and charging infrastructure designs. This model is also capable of simulating conventional taxi driving profiles. The validation of these simulation results with real taxi data showed that the model is reproducing taxi driving profiles with high accuracy in great detail. We found out that electric taxis could reach the same mileage and revenue as conventional taxis if charging with a power of 160?kW is possible. Furthermore, we discovered that waiting times for available charging stations have a stronger effect on revenue than the length of detours to reach charging stations. Based on these findings, we concluded that it is more important to reduce waiting times by placing sufficient numbers of charging stations at each location before expanding the charging network by installing small numbers of charging stations at many locations.     

A dynamic carsharing decision support system

This paper proposes a dynamic optimization–simulation model as a decision support system for one-way carsharing organizations. To reduce the vehicle imbalance in one-way systems, a Vehicle Relocation Optimization model is solved successively in a discrete event simulation. Each event is the arrival of a new user. The model is compared to an a priori benchmark model. Autoshare is chosen as a case study. Results show that increasing the reservation time (time between requesting and picking up a vehicle) from 0 to 30 min reduces fleet size by 86%. The model captures a tradeoff between vehicle relocation hours and fleet size.     

A model for taxi pooling with stochastic vehicle travel times

Taxi pooling means the sharing of a taxi by more than one passenger with at least a semi-common route. Currently, a trial-and-error process is adopted, taking into account expected travel times, for taxi pooling, a method which is neither effective nor efficient. This is because stochastic disturbances arising from variations in the taxi travel times that occur in actual traveling are neglected. In the worst case scenario, where vehicle travel times fluctuate wildly during operations, the planned schedule can be disturbed enough to lose its optimality. Therefore, in this study, a network flow technique is used to construct a stochastic taxi pooling model incorporating stochastic vehicle travel times. A solution algorithm is also proposed to efficiently solve the problem. The performance of the proposed models and the use of the solution method in practice are evaluated by executing numerical tests using real data with suitable assumptions. The test results show that the stochastic model and the solution method could be useful references for practice.     

A note on shared transportation for tourists with special reference to the Israeli sherut

In this note, we provide answers to two hitherto unstudied questions in the literature concerning the provision of shared transportation to tourists. First, we ascertain the long run fraction of time that there is no sherut taxi at a designated taxi stand. Second, we determine the long run fraction of tourists who are lost to the sherut taxi providing firm because no taxis are available when arriving tourists want a taxi. Finally, we show that these two long run fractions are equal because the so called PASTA property holds in our model. Copyright © 2009 John Wiley & Sons, Ltd.     

Three-stage airline fleet planning model

One of the main factors affecting airline success is bringing supply and demand as closely together as possible. In order to achieve this goal, an airline needs to adopt an appropriate methodological approach for the fleet planning process. Selection of an aircraft for operating a defined route network is a key element which has a direct impact on the increase of an airline's profitability and on the reduction of an airline's costs. The objective of this paper is to develop a robust model for fleet planning that deals with both fleet size and fleet composition problems for airlines operating on short haul and medium haul routes. The three-stage model for fleet planning involves approximate fleet composition, fleet sizing and aircraft type selection based on fuzzy logic, heuristic and analytic approaches, and multi-criteria decision making, respectively. This model is exemplified with a hypothetical airline based at Belgrade Airport.     

Analysis of ground access modes choice King Khaled International Airport, Riyadh, Saudi Arabia

Airports are vital to the transportation system because air travel is the fastest means of transporting people and goods around the world. Airports also connect aviation systems with other modes of transportation.As a result, access modes to airports are critical to the aviation system, and studying air passenger decisions regarding mode choice is an essential part of airport management and system planning.Though there has been systematic analysis of car use to access airports, there has been less systematic attention to the use of the public transport system, especially the taxi service. The aim of this study is to identify King Khaled International Airport (KKIA) access mode characteristics and users, which has not been investigated previously concentrating on the mix between car and taxi using data collected specifically for this research.More than half (55.5%) of the travelers surveyed arrived at KKIA by private car; taxi and limousine passengers accounted for 42.2% of the sample. The Saudi Public Transit Company (SAPTCO), transported only 2.3% of the air passengers surveyed. These results are similar to findings for an airport in the United States and very different from findings for an airports in the East (e.g., Hong Kong).A binary logit model was developed to evaluate the access mode choice. It was found that income, luggage, travel access time, and nationality significantly affect mode choice.Results provide insight for improved planning of access to KKIA.     

Mixed fleet dispatching in truckload relay network design optimization

We propose a mathematical formulation for strategic relay network design and dispatching method selection for full truckload transportation. The proposed model minimizes total transportation and installation costs of a mixed fleet dispatching system combining relay network and point-to-point dispatching. Operational constraints such as maximum driver tour length and load circuity are considered within the variable definition using predefined templates to generate feasible routes. High quality solutions for largely-sized problem instances are obtained in reasonable times. Computational results are analyzed to develop insights about the mixed fleet dispatching system and quantify its benefits over relay network-only and point-to-point dispatching.     

Urban bus fleet-to-route assignment for pollutant emissions minimization

This study proposes a methodology to optimize the assignment of an urban bus fleet to a set of fixed routes, taking into account the differences among routes and the differences among vehicle types and propulsion technologies in order to reduce pollutant emissions (CO₂, CO, THC, NO_x and PM). A Mixed Integer Linear Programming optimization model is stated and two scenarios are assessed: minimization of CO₂ and NO_x. The results show that it is feasible to obtain a fleet distribution in which emissions for any given pollutant are reduced without increase in emissions of other pollutants.     

Pricing strategies for a taxi-hailing platform

Taxi hailing apps that facilitate taxi-customer matching quickly become popular in recent years. By combining the theories of two-sided market and taxi market, this paper models the taxi market in the presence of a single taxi hailing app through an aggregate and static approach. Based on the equilibrium model, the existence and stability of equilibria are examined, and a partial-derivative-based sensitivity analysis is conducted to quantitatively evaluate the impacts of the platform’s pricing strategies to the taxi market performance. The features of desirable price perturbations that improve social welfare and/or the platform’s profitability are also characterized.     

Characterizing the movement patterns of minibus taxis in Kampala's paratransit system

Urban travelers in Africa depend on minibus taxis for their daily social and business commuting. This paratransit system is loosely regulated, self-organizing, and evolves organically in response to demand. Our study used floating car data to analyze and describe the movement characteristics of nine minibus taxis in Kampala, Uganda. We made three intriguing findings. Firstly, in searching for, picking up and transporting passengers, minibus taxi trajectories followed a heavy-tailed power-law distribution similar to a “Lévy walk”. Secondly, their routes' topology and shape gradually changed. Thirdly, the extraordinary winding (expressed in terms of tortuosity) of the paths suggested the extreme determination of the drivers' search for passengers. Our findings could help city planners to build on the self-organizing characteristics of the minibus taxi system, and improve the mobility of travelers, by optimizing routes and the distribution of public amenities.     

Examining the spatial-temporal relationship between urban built environment and taxi ridership: Results of a semi-parametric GWPR model

With the advance of intelligent transportation systems (ITSs) and data acquisition systems (DASs), it becomes possible in recent to explore the determinants of urban taxi ridership using multi-source heterogeneous data. This paper aims to use floating car data, points-of-interests (POIs) data and housing-price data to assess the influence of the built environment on taxi ridership. Within a scale of 0.5 km grid, critical indicators related to the economic aspect, intermodal connection, and land use factors were obtained using the multi-source data in Shanghai. To capture the spatial and temporal heterogeneity, Semi-parametric Geographically Weighted Poisson Regression (SGWPR) models are built over different time dimensions. It is found that SGWPR models result in higher goodness-of-fit than the generalized linear models. More importantly, the results show the impacts of built environment factors on taxi demand are highly heterogeneous, positive or negative in different city areas, reflected in the significant temporal variations of the effects. Overall, these findings suggest that the built environment factors have significant impacts on urban taxi demand, and the spatial context should not be ignored. Findings in this paper are expected to help better understand the relationship between urban taxi demand and built environment factors, improving the service level of the urban taxi system, and offering valuable insights into future urban and transportation planning.     

Urban taxis and air pollution: a case study in Harbin, China

Taxis share a high proportion of urban traffic volume and contribute a large proportion to urban air pollution. This paper addressees this context by exploring urban taxi air pollution emissions and possible reduction countermeasures. Based on a survey of Harbin taxis, we have developed different urban taxi pollution emissions models and considered taxi passenger occupancy and taxi average vacant ratio. To reduce taxi air pollution emission, this paper sets a reduction goal and puts forward three kinds of transport management policies. These are taxi market regulation, introduction of electric and Liquefied Petroleum Gas powered vehicles, and the introduction of dial-a-ride services. The paper provides recommendations for managing urban taxi development using these strategies.     

城市配送中心自有车辆规模研究

确定合理的自有车辆规模,是配送中心有效降低物流配送成本的措施之一。通过引入配送周期的概念,修正过去以天为周期计算配送中心所需车辆数的方法,从而得到能更准确反映配送中心用车情况的统计资料,在考虑内外车辆对客户服务水平的影响后,建立成本最小模型及模型求解方法,并结合算例计算出城市配送中心合理的自有车辆数。     

Dually sustainable urban mobility option: Shared-taxi operations with electric vehicles

Electric vehicles (EVs) are energy efficient and often presented as a zero-emission transport mode to achieve long-term decarbonization visions in the transport sector. The implementation of a sustainable transportation environment through EV utilization, however, requires the addressing of certain cost and environmental concerns such as limited driving range and battery-charging issues before its full potential can be realized. Nevertheless, a specific type of use of EVs, namely in taxi services, may elicit positive public opinion, as it promises a commitment toward sustainability in urban life. In light of this, this study proposes an integrated approach that combines EV operation with a conceptual design for shared-ride taxi services. As some productivity loss may be naturally expected due to the time spent in charging, it is important to look at whether such performance loss from the passenger and system standpoints can be offset with ingenuity in operational design. In this study, an EV taxi charge-replenishing scheme that can be coupled with a real-time taxi-dispatch algorithm is designed. The proposed EV charging schemes for taxi services are studied via simulations and the effects of the limited driving range and battery-charging details are examined from a system performance viewpoint. The simulation study also reveals illustrative results on the impact of the EV taxi fleet's operation on the charging system. Next, a real-time shared-taxi operation scheme that allows ride sharing with other passengers is proposed to maximize the operational efficiency. The simulation results suggest that the shared-taxi concept can be a viable option to improve on the limitations caused by EV operation. In addition, the importance of projected charging demands and queue delays at different charging locations are also addressed. Some limitations and a future research agenda are also discussed.     

Endogenous treatment of residential location choices in transport and land use models: Introducing the MetroScan framework

Within a random utility maximisation modelling framework, the paper develops a residential location choice model as part of an integrated transport and land use modelling system, called MetroScan – a quick scanning tool to evaluate transport and land use initiatives, including benefit-cost analysis and economic impact analysis. We describe how the developed model is integrated, as an empirically calibrated module, into the behaviourally richer transport and land use modelling system of MetroScan for practical application. A full application of MetroScan modelling system to Sydney West Metro link recently proposed by the New South Wales government is presented as a case study. The results demonstrate how the residential location choice model works with other inter-connected models, such as work and non-work location choices, dwelling tenure and dwelling type, and vehicle fleet size choice embedded in the modelling system, in simulating the impact of transport and housing development on household choices of residential location.