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Note: To enable this function, activate the Mobility Sharing add-on module ( Enabling or disabling add-ons). |
The modeling of vehicle sharing, i.e. the organized sharing of modes of transport, is an extension of timetable-based assignment in Visum. This allows you to model rental systems separately or as a PuT path leg. Several sharing systems may be used at the same time and allow you to model car and bike sharing offers. The software distinguishes between the following systems that can be modeled:
- Non station-based systems
- Station-bound systems
- Full flexibility of return station
- Return of rental vehicles at pickup station only
In addition, the procedure models the following additional properties of vehicle sharing systems:
- Trips that start or end with a rental or return operation or that end at destinations (zones) where users keep the vehicles for a certain period and then continue with their journey.
- If a sharing system does not have its own infrastructure, it may be assigned to a conventional PrT transport system. It can then use its supply, but is also dependent on its traffic situation.
- The number of sharing vehicles is very low compared to the number of conventional vehicles. Thus, the sharing vehicles have no impact on the traffic volume and traffic situation of conventional PrT.
- The vehicles are booked in advance and a booking period must be specified depending on the type of system used.
- The number of vehicles available in the system is limited.
- The rental and return of vehicles takes time.
- If capacity utilization of the sharing system is very high, it becomes more difficult to rent a vehicle.
- Stations have a fixed number of parking spaces (capacity) and a number of available vehicles (occupancy).
- Users pay for using sharing system services. User costs always have a time-dependent component.
- For non station-bound systems and systems where the pickup and return stations do not have to be the same, operators have expenses for the relocation of vehicles.
Elements of modeling
There are specific elements or attributes in the transport model that allow you to model sharing systems.
Transport system
To model vehicle sharing transport systems, select the type Sharing when you create a transport system. As soon as this transport system is available in PuT, it is taken into account for timetable-based assignment. Additional properties of the sharing system can be set under the transport system.
- Vehicle sharing system
The sharing system type you select has an impact on the use of the vol/cap-dependent impedance component and the search function (Calculating vol/cap ratio-dependent impedance).
- Capacity of the system
The capacity of the sharing system depends on the number of rental vehicles. Operators can increase availability of the vehicles by allowing interlining and providing a vehicle depot.
- Occupancy rate
The OD trips used in PuT must be converted to vehicles to model the PrT-based vehicle sharing system. This is done with the help of the occupancy rate entered by the user.
Sharing stations
Rental operations begin and end at a station. Stations are thus the start and end points of sharing path legs. A station is linked to the network via its access node. Stations may contain rental vehicles of different transport systems.
Stations have a specific capacity which corresponds to number of their parking spaces. This capacity is independent of a transport system. This means all parking spaces are available to all transport systems enabled for use. Different types of parking spaces can only be modeled separately through an additional station, if necessary at the same access node.
Stations must initially be assigned vehicles. This occupancy is then used for the assignment procedure in the first time slice. For stations you can choose between temporary or constant optimal occupancy. Optimal occupancy is used during relocation procedures (Relocation procedure).
The rental and return of a vehicle at a station causes extra time and effort for users. It includes accessing and leaving the station as well as selection of and payment for the rental vehicle. This additional effort can be saved per station and later becomes part of the sharing path leg.
Traffic zones
Rental vehicles are often not only used to drive from one station to another. In systems where the pickup and return station must be the same, this scenario is even excluded. In fact, rental vehicles are mostly used to get to a destination where the vehicle is parked for a while and the driver pursues an activity. During this time, the vehicle is still rented. After the activity has been completed, the vehicle is used again. The model records the Number of parked rental vehicles and Number of collected rental vehicles per time slice. In the transport model, the destinations lie within zones. The average dwell time is an input attribute for zones and affects search impedance through the time-dependent aspect of the fare. The minimum dwell time affects the re-availability of the rental vehicle after arrival and thus allows for realistic modeling of its frequency of use.
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Note: In the directory C:\Users\Public\Documents\PTV Vision\PTV Visum 2022/Examples, you can find examples of use on this topic. The Vehicle Sharing examples (bike sharing and car sharing) describe the modeling of bike and car sharing systems (one-way system/round trip system) and their consideration within a timetable-based public transportation assignment. In addition to the steps for designing a model, the essential procedure parameters are presented and advice is given on the correct modeling and evaluation of the results. |
