Network objects

The transport supply consists of several transport systems. Transport systems are used, for example, to allocate attributes for network objects dependent on transport systems. This is how links can be opened for a transport system bike, for the transport systems car and HGV blocked, however.

In PrT a mode comprises exactly one transport system. In PuT, however, a mode can comprise several transport systems. This is how you can define a mode PuT for example, which comprises the PuT transport systems tram, bus, and train.

A demand segment makes the connection between transport supply and traffic demand. A demand segment is assigned exactly one mode and each demand segment exactly one demand matrix. A mode can comprise several demand segments. This is how you can create a demand segment for the mode PuT, for transporting students, and one for the remaining PuT.

Nodes are point objects, which specify the location of intersections, merging links, or switches in the road and rail network. They are the start and end points of links. Nodes connect zones with the network (connected nodes).

Turns specify which movements are permitted at a node, that is, whether turning at a node from one link to another link is permitted.

For PrT transport systems, turning time penalties and capacities can be specified which describe the influence of the intersection on the performance of the network.

Turning prohibitions are taken into consideration as follows:

• For public transport systems in the construction of a line route
• For private transport systems in a route search

Turn standards are templates used to create new turns with default values for the attributes Time penalty and Capacity PrT. Which turn standard is used for the allocation of turn attributes, depends on the node type, the turn type, and the flow hierarchy.

Links connect nodes and thus describe the structure of the road and rail network. A link is a directed edge, i.e. both directions of a link are independent network objects and thus, can have different attributes.

Link types are used as a template when inserting new links. When inserting a link, a link type has to be specified. The link then takes over the attributes permitted transport systems (TSysSet), Capacity PrT, velocities (v0-PrT, vMin-PrT, vMax-PrT, and vDef-PuT), Number of lanes, and the link rank as default values.

Zones (traffic cells) describe the positions of utilities in the network (for example, residential areas, commercial areas, shopping centers, schools). They are origins and destinations of movements within the transport network, which means of traffic. Zones and the transport network are connected through connectors.

Connectors connect zones to the link network. They represent the distance to be covered between a zone’s center of gravity and the connector nodes. For public transport demand, the zone has to be connected via a stop area with stop(s) allocated to a node.

Several nodes can be aggregated to one main node. Each node is only allowed to be part of a main node. Using main nodes is useful if the Visum network is strongly disaggregated and lanes are available as individual links, for example, and intersections, therefore, consist of several nodes (this situation can occur when working with navigation networks in Visum).

Main turns are created when using main nodes. Each movement via the main node is represented by a main turn. Main turns possess the same attributes as turns. In the assignment, the main turn replaces the node turn, which has the effect that only one turn penalty flows into the assignment for each main turn.

Main zones group multiple zones and allow aggregated evaluations. A main zone can represent a county for example, which has multiple communities as traffic cells.

Territories are network objects, which can be used, for example, to illustrate districts or counties. Based on a polygon that defines the territorial border, PrT and PuT indicators can be precisely accounted for each zone (for example the driven service kilometers within a zone).

OD pairs exist between all zones of the network. The values in skim matrices and demand matrices (Matrices) refer to one OD pair each. Compared to the other network objects, you cannot edit OD pairs interactively in the network editor, but you can filter OD pairs and display them graphically. For each OD pair, you can select the skim matrix values, the demand matrix values, and the direct distance as attributes.

For assignment calculation, paths are found between the origin and destination zone, and their volume is calculated. Paths are therefore the central result of the assignment procedure. In PrT, the user can manually edit paths. This is how the assignment results could be manually imported to Visum or the Visum assignment results could be adjusted manually. Both the path volumes and the course of the path can be edited.

A valid day is a freely definable set of days of the calendar used. If a weekly calendar is used, a valid day may comprise the days from Monday to Sunday (e.g. "Monday to Friday"). If an annual calendar is used, any individual days can be selected within the validity period. If no calendar is used, there is only the valid day "daily". It is then not possible to create new valid days.

In PuT: a valid day can be assigned to each vehicle journey section.

In PrT: in the simulation-based dynamic assignment, dynamic stochastic assignment, and DUE, traffic supply can be time-varying. Time-varying attributes are used (Time-varying attributes). When using a calendar, valid days can be specified for these time-varying attributes, on which they should have an effect.

The time interval set is user-defined and has one or more time intervals. The time intervals of a set must not overlap. However, the time intervals do not have to cover a period without gaps. The time intervals of exactly one time interval set define the analysis time intervals. User-defined time interval sets are suitable for time input data and enable the aggregation of time attributes to other time intervals of other sets.

A stop combines stop areas and therefore also stop points. To ensure that a stop can be localized and displayed in graphical form, it has a coordinate, but it is not assigned directly to a network node or link.

A stop area divides a stop into areas. It can, for example, represent a train station platform, intersections with multiple stop points, or a station concourse. A stop area has the following properties:

• It is assigned exactly one stop.
• It can comprise multiple stop points.
• It can be assigned a network node. This allows a PuT connection of a zone to the road network.
• The stop areas are connected with a transfer walk matrix (walk times between the stop areas). It contains the transfer walk time of each PuTWalk for example.

A stop point is a location, where PuT lines stop for passenger boarding. A stop point can either lie on a node or a link (link stop point).

• A stop point at a node can be served by all lines that pass the node.
• A stop point on a link can only be served by lines that pass this link. A detailed direction modeling based on masts is optionally possible with link stop points. Alternatively, undirected stop points can also be inserted on links.

Lines combine all line routes and timetables of a line. A line has at least one line route and this line route has at least one time profile. For line variant modeling, several line routes can be specified for the line, and several time profiles can be specified for each line route.

Line routes describe the spatial course of the line route for one direction as a sequence of route points. Route points are selected points in the line routes, namely all stops and possibly traversed nodes. The first and last route point of a line route must be stop points that are open for the transport system of the line.

Time profiles describe the length of travel times between stop points of a line route and if boarding or alighting is allowed at the stop points of the line route. Since it is possible to create several time profiles per line route, you can model, for example, that the travel times of a tram between stop points are longer during evening rush hours than during the rest of the day. Time profiles are allocated at vehicle journey level so that each vehicle journey can be allocated a different time profile.

Vehicle journeys (also called journeys only) are the basic objects to describe the timetable. Each vehicle journey has exactly one time profile. In most cases, all vehicle journeys of a line route use the same time profile if it does not vary depending on the time of day.

Vehicle journey sections (also called journey sections) are used to sub-divide a vehicle journey. You can define different valid days and different vehicle combinations for the individual vehicle journey sections of a vehicle journey. This is how you can achieve, that a train travels on days with high saturation with a vehicle combination, which has more coaches attached. Furthermore, you can specify different start and end points for each vehicle journey section, and therefore achieve for example, that the additional coaches are only attached to one part of the line route course.

Main lines are used to aggregate several lines and evaluations (such as for PuT operating indicators) on this aggregation level. Aggregation can also be carried out via lines with different transport systems.

A system route describes the in-vehicle time and the spatial course between two stop points. Compared to the line route, it is independent of the affiliation to a line or even a concrete vehicle journey. System routes, with their path and in-vehicle time information, are used as a template for the efficient editing of line routes and to set in-vehicle times in the time profile. System routes are optional network objects, therefore not mandatory when creating a PuT model.

You can assign an operator to each vehicle journey section. When working with the operator model, you can evaluate PuT operating indicators per operator (Operator model PuT). Furthermore, you can assign each operator cost values for depreciation and running costs, and then evaluate operator costs referring to different network objects.

You can optionally assign each vehicle journey section a vehicle combination. To a vehicle combination you can allocate time and distance dependent cost rates for vehicle journeys and empty trips, and cost rates for the layover in the depot and the stand time. These cost rates are applied within the operator model (Operator model PuT).

A vehicle combination consists of one or more vehicle units. This is how you can compose a vehicle combination Intercity out of several vehicle units Coach, for example. For each, you can specify the number of seats and total seats. Furthermore, you can assign time and distance dependent cost rates for vehicle journeys and empty trips, and cost rates for the layover in the depot and stand time. You can also define a fixed cost rate per vehicle. This allows much differentiated modeling of your vehicle pool.

In Visum multiple line blocking results can be kept simultaneously. These are saved in so-called block versions. This is how alternative plans with different parameter settings can be compared with each other. In the model, for example, one block version can be kept where interlining is allowed, and another block version where it is not allowed.

Each block is composed of individual sections, which are called block items. Each block item is of a special type (block item type). By default, Visum provides the block item types vehicle journey, empty trip, layover time, and stand. You can also create user-defined block item types and include these manually in your blocks (for example for maintenance or wash).

If revenues are modeled with a fare model, the ticket type creates the basis for the fare calculation of a connection. Basic fares and transport system dependent supplements can be defined.

For revenue calculation with fare model and zone-based fare, fare zones are used to calculate the fare of a connection. For the zone-based fare, this complies with the number of traversed fare zones. To determine the number of traversed fare zones, stops are assigned to the fare zones.

This network object is only relevant for headway-based assignment. If there are two lines for example, which complement each other on a common section of the route course to a headway interval half the length, we speak of coordination. The coordination group combines two or more time profiles over a common section of the line courses. If two or more time profiles were coordinated via a route section, they behave like a time profile with a corresponding increased frequency on this section. The random variable, which illustrates the waiting time within headway-based assignment, thus is reduced to the coordinated section.

Points of Interest are user-defined network objects with a spatial reference, e.g. parking facilities, pre-emption points for AVLS (automatic vehicle location systems), or signal controllers in public transport. POIs are used to display special land uses such as restaurants or hotels, for data management as well as for reachability analyses.

A count location is an independent network object allocated to a link by direction. Count locations serve for data management and display of counted link data.

Detectors are optional network objects of the count locations add-on. They are used for lane-based management of count data and signal control modeling.

Toll systems are optional network objects which can be used to integrate toll zones into the network model. For the TRIBUT procedure, they are the basis for the calculation of road tolls.

GIS objects (GIS = geographic information system) extend the network model by special layers which are directly incorporated from GIS ArcGIS and can be linked with the Visum network data via blending features. The objects are only available while you are connected to a Personal Geodatabase (PGD).

Screenlines are a useful construction to calibrate an assignment model using counted link data. The course of a screenline often follows natural realities, rivers or railway tracks, for example.

A location represents a place in the network where people live in households and where activities can take place. A location can be assigned to a zone or POI.