VISSIM 5.30-05 User Manual

6 The Traffic Network
6.3 Network Coding
The level of detail required for replicating the modeled roadway infrastructure
depends on the purpose of a VISSIM application. While a rough outline of
the analyzed intersection is sufficient for testing a traffic actuated signal logic,
a more detailed model is required for simulation analyses. With VISSIM it is
possible to model virtually any kind of intersection (or sequence/network of
intersections) with a precision down to one millimeter!
In the event of using VISSIM to test traffic actuated controls through interactive,
manual detector activation, it is recommended to create a rough
model of the analyzed intersection including all approaches. However, it is
not necessary to place the stop lines and detector loops at the exact
positions.
For the purpose of simulating traffic operations, it is necessary to replicate
the modeled infrastructure network to scale. This can be done as follows:
► Import of a scaled network from VISUM, CROSSIG, P2 (or other applications
that provide VISSIM network files)
► Import of a scaled network from the signal control optimization software
package SYNCHRO (additional module, cf. section 6.2 for details)
► Import of base maps or drawings as a background so that the VISSIM
network can be traced exactly according to a scaled map (cf. section 4.4
for details)
6.3.1 Links
Network elements can be moved not only within the same link/connector
but also to any other link/connector.
Also the start and end of a connector can be moved to a different link.
Input flows can be placed on another link in the Input flows window only.
The start of PT routes cannot be moved.
If you are starting with an empty network in contrast to an imported one, you
need to ensure that the scaling is right before you start to code the VISSIM
network. This is done using at least one scaled background graphic. For
details on how to load, move and scale a background images, please refer to
section 4.4.
The first step in coding a VISSIM network is to trace links. Therefore look for
all of the approaches to an intersection and determine the number of lanes
both on the approach and within the intersection. Each approach and section
will be represented by one link. Start with the major roads.
To generate the opposite direction of a link, option Generate Opposite
Direction has to be checked. The newly created link can have a different
number of lanes. A link always should represent the real shape in the road
network.
184 VISSIM 5.30-05 © PTV AG 2011