Inputs, routing decisions and routes guide pedestrians

Pedestrians are added to the network via pedestrian inputs, they are distributed across the pedestrian routes based on pedestrian routing decisions and partial pedestrian routing decisions. They then follow the routes to their destinations.

Using pedestrian inputs to add pedestrians to a network

You can either define pedestrian inputs to pedestrian areas, add pedestrian routing decisions, partial pedestrian routing decisions, and pedestrian routes, or have pedestrian inputs automatically generated from a origin-destination matrix while also generating routing decisions and routes to their destinations (Pedestrian OD matrices).

• You must define pedestrian routing decisions for pedestrian areas for which pedestrian inputs are defined, where pedestrian routes begin.
• At least one pedestrian route per pedestrian is required that is included in a time interval of the pedestrian input and belongs to the pedestrian composition of the input. This is automatically the case, when for the routing decision, you specify the attribute AllPedTypes (All pedestrian types). However, if you choose a pedestrian class that only includes some of the pedestrian types, a pedestrian type might be used at the pedestrian input, but no pedestrian route will be defined for it. In this case, the simulation would be canceled and an error message displayed. A routing decision, for which the relative volumes of all routes are set to NULL for a time interval, is treated as if it did not exist.
• The pedestrian routing decision allocates a pedestrian route to each newly created pedestrian for which the pedestrian type or class is selected. If there is more than one pedestrian route for a specific pedestrian type, a route is chosen randomly according to the relative volumes of individual routes.
• Each pedestrian route leads from its routing decision through a sequence of areas and ramps to its final route location, the destination.

Strategic routes guide pedestrians throughout the network

• A pedestrian always walks towards his next routing point.
• When a pedestrian reaches a route location which has been assigned a time distribution in the attribute TmDistr (Time Distribution), he waits for the period defined.
• If this was not the pedestrian's last route location, he walks on to the next route location.
• However, if this was the last route location of his route and if the area of the route location contains a routing decision with routes for this pedestrian type or class, he is assigned a new route that he will continue to follow.
• If there is no route for the pedestrian, he is removed from the network.
• If the area with the last route location contains a pedestrian input, the pedestrian is removed from the route, as it is assumed that routing decisions on areas that contain a pedestrian input are specifically meant for new pedestrians coming from this input.
• If the last route location lies in an area that has been assigned the attribute PTUsage > Waiting area, the pedestrian remains in the Vissim network, if there is no routing decision for this area. He waits for a suitable public transport vehicle to board (Attributes of areas) and (Modeling pedestrians as PT passengers).
• There may be several "tactical" options for pedestrians to get from one route location to the next. For example, they can pass by obstacles, keeping left or right or use stairways or ramps to get to their destination. Moreover, pedestrians must be able to sidestep each other. Viswalk automatically performs the calculations and makes the decisions for such actions during the simulation. In multi-level scenarios, Viswalk internally computes a routing graph. The routing graph consists of the route locations you defined and additionally contains a route location for both ends of each stairway or ramp on the route. The routing graph thus includes relevant information on all routing variants that lead via the same level or via different levels that are connected via stairways or ramps. Based on the routing graph, Viswalk determines the shortest path between two route locations. The shortest path is used for the pedestrian's tactic movement. In Viswalk, pedestrians prefer routes without stairways or ramps, even if these are shorter. If instead you would like pedestrians to use stairways or ramps, place your route locations on the desired ramps.

Requirements for assigning routing decisions

The following requirements must be fulfilled for a pedestrian to be assigned a new route.

• A routing decision has been defined for this area.
• The routing decision must be applicable to the pedestrian type based on class dependency.
• The pedestrian currently has no route. The might be due to the following:
• The pedestrian was newly generated.
• In this time step, the pedestrian has reached the final route location of his current or previous route.
• The pedestrian has alighted from a public transport vehicle and is entering an area that has been assigned the attribute PTUsage > Platform edge (Attributes of areas) and (Modeling pedestrians as PT passengers).
• Viswalk can allocate multiple static pedestrian routes and, at most, one partial pedestrian route to a pedestrian within a single time step. Viswalk does not allocate the same static pedestrian route to a pedestrian more than once within a single time step. When multiple routing decisions are accessible that impact the pedestrian's pedestrian class, Viswalk allocates the routing decision with the lowest number. If the pedestrian is unable to select this routing decision, Viswalk assigns the routing decision with the next lowest number. This situation may arise, for instance, if the pedestrian routes associated with the routing decision have a volume of ZERO.
• If the Every time step option is selected for the Decision Model of a partial pedestrian routing decision, Viswalk can assign another partial route from this partial routing decision to the pedestrian. However, the pedestrian must be located within the area of the partial routing decision. If a time distribution is assigned to the area, it does not take effect in this context.