This session covers various aspects of carsharing, including parking demand, influence of walking and public transport accessibility, service reliability, subleasing, and data framework.
The Spatial Reconfiguration of Parking Demand Due to Car sharing Diffusion: a Simulated Scenario for the Cities of Milan and Turin (Italy)
Marco Diana, Politecnico di TorinoShow Abstract
Andrea Chicco (firstname.lastname@example.org), Politecnico di Torino
One of the most expected benefits from the diffusion of car sharing services in urban areas is the decrease of car ownership levels and related impacts in terms of vehicle miles traveled, greenhouse gas emissions, and space consumption. Unlike previous studies in which the effects on public spaces are related to a reduced number of private vehicles, in this paper we present a method to analyze the spatial variation in parking demand in a city with the joint consideration of the kind of parking actually in use. A distinction is made between dedicated parking areas from on-street parking. A trip-level analysis approach is then followed, where car ownership is an exogenous variable and modeling scenarios on modal diversion patterns for different origin-destination pairs are examined. Travel demand models are calibrated and validated on a stated-preferences travel survey carried out in Turin in 2016 and applied on a revealed-preferences travel survey distributed in the cities of Milan and Turin (Italy) in May 2019. Both surveys were administered to a representative sample of the population living in the cities, therefore results can be generalized. The planning scenario resulting from modal diversion patterns show that free-floating car sharing might produce positive and negative impacts on both on-street and on-surface dedicated parking areas. In particular, more positive impacts are expected on daily parking events in central areas, where mobility attractors are concentrated. On the contrary, higher negative impacts on both on-street and dedicated parking events might be encountered in more peripheral areas.
Evaluating an Innovative Sub-Leasing Type of the Round-trip Carsharing
Samira Ziyadidegan (email@example.com), Texas A&M University, College StationShow Abstract
Luca Quadrifoglio, Texas A&M University, College Station
Elena Floris, Universita degli Studi Di Cagliari
Matteo Gravellu, Universita degli Studi Di Cagliari
Eleonora Sottile, Universita degli Studi Di Cagliari
This study introduces a sub-leasing type of round-trip carsharing to enhance its efficiency for both customers and companies. This innovative type of carsharing provides new temporary stations and allows customers to access vehicles both in the company's stations and vehicles already reserved but parked and unused in other locations. The evaluation is performed using simulation and available demand datasets. Results show that the proposed model significantly increases the acceptance rate of the reservation, the availability of the company's vehicles and reduces the needed number of vehicles in the fleet, enhancing the revenue of companies. Hence, it provides many benefits for both companies and customers. Sensitivity analyses quantify the expected improvement due to assuming a higher acceptable walking distance for customers and to increased flexibility of the customers’ reservation times.
Adhesion to Shared Mobility: An Analysis of the Influence of Walking and Public Transport Accessibility to Vehicles on Carsharing Membership in Montreal, Canada
Mathilde Roblot, Universite de Technologie de CompiegneShow Abstract
Genevieve Boisjoly (firstname.lastname@example.org), Ecole Polytechnique de Montreal
Francesco Ciari, Ecole Polytechnique de Montreal
Trépanier Martin, Ecole Polytechnique de Montreal
In the context of sustainable mobility policies, carsharing services have gained importance as an alternative to personal vehicles. In an effort to increase the adherence to and use of such services, several studies have explored the key factors that determine use and membership. While the ease with which individuals can access shared vehicles appears to be a central determinant, few studies have specifically investigated how to measure station and vehicle accessibility. To fill this gap, this study seeks to systematically assess and compare the contribution of different accessibility indicators to modeling carsharing adhesion, using 2016 data from the Montreal carsharing company Communauto and from the Canadian census. Three indicators of accessibility to in-station vehicles are generated: walking only, public transport only and multimodal accessibility (walking and public transport), considering a variety of travel time thresholds and cost functions. A linear regression model is then generated to assess the contribution of the different indicators to modeling membership rates, while controlling for socio-economic and commuting characteristics. The results show that walking accessibility, within 20 minutes, and public transport accessibility, within 40 minutes, are both key determinants of membership rate and in a complementary manner. The influence of public transport accessibility is positive and highest when walking accessibility is low. The results also demonstrate that the use of a cumulative or weighted opportunity indicator is equally sound from an empirical perspective. The study is of relevance to researchers and planners wishing to better understand and model the influence of vehicle accessibility.
ONE-WAY CARSHARING SERVICE DESIGN UNDER DEMAND UNCERTAINTY: A SERVICE RELIABILITY-BASED TWO-STAGE STOCHASTIC PROGRAM APPROACH
Wentao HUANG, Hong Kong University of Science and TechnologyShow Abstract
Wei Huang, Sun Yat-Sen University
Sisi Jian (email@example.com), Hong Kong University of Science and Technology
This study proposes a service reliability-based two-stage stochastic program approach for one-way carsharing systems. The objective is to improve the profitability for one-way carsharing operators under demand uncertainty. We first formulate the two-stage stochastic model, where stage 1 determines the strategic and tactic deployments for the regular service, including the number of vehicles, personnel and parking lots. Upon realization of the random demand, stage 2 deploys ad hoc services and optimizes vehicle relocation and personnel assignment. The ad hoc service is integrated into the model, which serves the demand that cannot be satisfied by the regular service. Further, a SR-based gradient descent algorithm is developed to find the optimal SR. Finally, the performance of the proposed model and algorithm is tested with a numerical study. Sensitivity analysis over the degree of demand variation and ad hoc service cost are conducted. Results show that up to 19% improvement in profit can be achieved by the proposed stochastic approach compared to the solution obtained by the deterministic model.
AProposed Data Framework for Car Clubs and LocalAuthorities in the UK
Chenyang Wu, Southeast UniversityShow Abstract
Aruna Sivakumar, Imperial College London
Scott Le Vine, Imperial College London
Ivo Wengraf, RAC Foundation
Paulius Mackela, London Councils
Car clubs (carsharing operators) in the UK typically seek privileged access to on-street parking, and thus Local Authorities (municipalities) have a reasonable desire to understand the impacts of their operations. Failure to coordinate between the operators and Local Authorities would mean that the benefits of car clubs are not fully realised. However, a generic data sharing framework between car club operators and Local Authorities in the UK has not been established, despite car clubs being active for some two decades. Data exchanges remain ad-hoc and inconsistent across Local Authorities, and the lack of a common data sharing framework is inefficient in various respects. The objective of this study is to propose a data sharing framework to fill this gap, to be known as CLADS (Car club-Local Authority Data Standard). Developing this framework involved three workstreams: Reviewing existing related data standards; Interviewing senior staff at cities abroad facing similar issues; and Hosting a series of three stakeholder workshops. Following a summary of the approach to developing the data standard and presentation of the specifications, we then present prospective use cases through two fictional case studies.
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