Updating impedances at nodes

For example, you can use this feature to test the node performance. It is only effective for nodes for which the impedance method ICA (Intersection Capacity Analysis) is specified (Calculating node impedances).

If you want to update the impedance of a node that has an associated signal control, you can specify that the signal cycle and split optimization is carried out for the signal controller at the same time. The optimization will then be done automatically for all nodes or main nodes of the signal controller while the impedances are updated.

You can execute the functionality for all, all active nodes, or marked nodes.

Editing all or all active nodes

1.  Select the nodes whose impedances you want to update. To do this, use

The selected nodes are active.

2.  In the Network window, right-click the Nodes button.

The Nodes shortcut menu opens.

3.  Select the entry Update impedances/Optimize signal controller.

The Update node impedances window opens.

4.  If necessary, select the Only edit active objects option.

5.  If you want to execute the signal cycle and split optimization for nodes with a signal controller, select the Signal cycle and split optimization option.

Element

Description

Signal cycle and green time optimization

If this option has been selected, Visum checks for all nodes with a signal controller which optimization method has been specified for the signal controller (Properties and options of signal controllers). Dependent on the specified optimization method, no optimization, only the signal split optimization or the signal cycle and split optimization is carried out.

Use global design hourly volume

If the option is selected, the global design hourly volume set under Calculate > General procedure parameters > PrT settings > Node impedances is used for optimization.

Use design hourly volume from attribute

If the option is selected, specify a numerical turn attribute for the optimization, which is multiplied by the specified factor.

If there are main turns, the selected attribute must also exist for main turns so that the optimization can be performed.

6.  Confirm with OK.

The impedances are updated. If the Signal cycle and split optimization option has been selected, for nodes with a signal controller either no optimization, only the signal split optimization, or the signal cycle and split optimization is carried out. This depends on the optimization method specified for the signal controller.

Note: If a node is allocated to a signal controller, impedances and optimizations are always calculated simultaneously for all nodes and main nodes that are allocated to this signal controller.

You can also execute the signal cycle and split optimization for individual or all active nodes (Optimizing signal cycles and split of a single signal controller and Optimizing signal cycle and split times).

Editing marked nodes

1.  In the network, mark all nodes whose impedances you want to update.

2.  Right-click in the network display.

A shortcut menu opens.

3.  Select the entry Update impedances/Optimize signal controller.

4.  If you want to execute the signal cycle and split optimization for nodes with a signal controller, select the Signal cycle and split optimization option.

5.  Confirm with OK.

The impedances are updated at the selected nodes. If the Signal cycle and split optimization option has been selected, for nodes with a signal controller either no optimization, only the signal split optimization, or the signal cycle and split optimization is carried out. This depends on the optimization method specified for the signal controller.

Tip: You can also call the function from the shortcut menu of the corresponding list and edit marked objects together.