Free-floating car-sharing schemes operate without fixed car-sharing stations, ahead reservations or return-trip requirements. Providing fast and convenient motorization, they attract both public transportation users and (former) car-owners. However, given their highly flexible nature and different pricing structures, previous findings on user groups and environmental impact of station-based car-sharing may not be easily transferable. Therefore, this research uses survey data to directly compare user groups and usage patterns of a free-floating and station-based carsharing service both operating in the city of Basel. The findings suggest, that the schemes indeed attract different user groups and are also used differently. Moreover, it is shown, that car-sharing membership is governed by other factors than car-sharing activity. Given the observed structural differences, the environmental impact of free-floating car-sharing is yet to be determined.

No abstract

Automated Vehicles (AV) promise many benefits for future mobility. One of them is a reduction of the required total vehicle fleet size, especially if AVs are used predominantly as shared vehicles. This paper presents research on this potential reduction for the greater Zurich region, Switzerland. Fleets of shared AVs, serving a predefined demand, are simulated with a simulation framework introduced in the paper. Different scenarios are created, combining different levels of demand for AVs with different levels of supply (i.e. AV fleet size). An important contribution of this study is the use of a spatially and temporally highly detailed travel demand, going beyond the simplifications of previous studies on the topic. This provides a more solid basis to the ongoing discussion on the future fleet size. It is found that, for a given fleet performance target (here 95% of all transport requests are served within 5 minutes), the relationship between served demand and required fleet size is non-linear and the ratio increases as demand increases. There is a scale effect, which has the important implication that for different levels of demand the fleet is used more or less efficiently. This paper also finds that, if waiting times of up to 10 minutes are accepted, a reduction of up to 90% of the total vehicle fleet can be possible even without active fleet management like vehicle redistribution. Such effects require, however, that a large enough share of the car demand can be served by AVs.

This study provides a large-scale micro-simulation of transportation patterns in a metropolitan area when relying on a system of shared autonomous vehicles (SAVs). The six-county region of Austin, Texas is used for its land development patterns, demographics, networks, and trip tables. The agent-based MATSim toolkit allows modelers to track individual travelers and individual vehicles, with great temporal and spatial detail. MATSim's algorithms help improve individual travel plans (by changing tour and trip start times, destinations, modes, and routes). Here, the SAV mode requests were simulated through a stochastic process for four possible fare levels:

Carsharing, in any form, is still growing around the world. One of the effects is the increasing number of cities in which multiple carsharing operators are competing. The carsharing industry has never been as competitive as it is now: the present is a good time for researchers to invest efforts in providing tools for the assessment and planning of carsharing programs. Nevertheless, efforts in this direction are still scarce, in particular for some of the newest forms in which carsharing has been implemented, such as free-floating carsharing. This paper reports on a study that made use of MATSim, an agent-based simulation software that had already been used to model station-based carsharing, to evaluate different carsharing scenarios for the city of Berlin. The main findings are the existing high potential to extend carsharing services further in Berlin and the apparent complementarity of station-based and free-floating carsharing. On the methodological level, the work introduces a new tool for the modeling of free-floating carsharing along with improvements of the previously existing station-based carsharing model.

Mobility as a Service (MaaS) aims to allow less biased mode choice decisions by overcoming market segmentation. To this end, all available modes are offered at their respective marginal cost for each trip. Such a setting favors shared modes, where fixed costs can be apportioned among a large number of users. In turn, car-sharing, bike-sharing or ridehailing may themselves become an efficient alternative of public transport. Although early field studies confirm the expected changes in behaviour, impacts have not been studied for larger transport systems yet. This research conducts a first joint simulation of car-sharing, bike-sharing and ride-hailing for a city-scale transport system using MAT-Sim. Results show that in Zurich, through less biased mode choice decisions, transportrelated energy consumption can be reduced by 25 %. In addition, introduction of shared modes may increase transport system efficiency by up to 7 %. Efficiency gains may reach 11 % if shared modes were used as a substitute for public transport in lower-density areas. Hence, a MaaS scheme with shared mobility allows to increase system efficiency (travel times & cost), while substantially reducing energy consumption.

Free-floating car-sharing schemes operate without fixed car-sharing stations, ahead reservations or return-trip requirements. Providing fast and convenient motorization, they attract both public transport users and (former) car-owners. Thus, their impact on individual travel behavior depends on the user type. Estimating the travel behavior impact of these systems therefore requires quantitative data. Using a two-wave survey approach (shortly after launch of the scheme plus one year later) including travel diaries, this research indicates that (due to their membership) 6 % of the free-floating car-sharing customers reduce their private vehicle ownership. Moreover, the results suggest that freefloating car-sharing both complements and competes with station-based car-sharing.

Carsharing is a system that allows individuals to use a car from a fleet on an hourly basis.