VISSIM 5.30-05 User Manual

6 The Traffic Network
The illustration shows both scenarios.
The South approach is a combination
turn lane and the West approach is an
exclusive turn lane. The lighter bars are
signal heads and the darker are stop
signs.
6.6.4 Merging and Weaving Sections
In order to get the best vehicle behavior it is important to implement merging
and weaving sections in VISSIM properly.
Here are the important things to remember:
► The merge section (weaving section) should be one link with the number
of lanes equal to the number of lanes on the main freeway plus the
number of lanes merging onto the freeway.
► There should be only one connector after the merge link (weaving
section) to the main freeway. For graphical reasons an additional dummy
link (not a connector) can be added at the end of the merging lane(s) to
smoothen the lane reduction.
► The through movement needs to follow a route in order to prevent it from
using the acceleration lane(s). This route must end no sooner than on
the main link after the merge link. Additionally the Lane Change distance
for the connector downstream from the merge link (weaving section)
must be larger than the length of the merge link itself. If this is not the
case, a vehicle from a through lane may change to the acceleration lane
(merging lane) and then needs to get back to the main link thus
producing unrealistic lane changes.
► The routes of the merging traffic must also extend past the merge link
(weaving section). If not, vehicles on the merge link will not know that
they need to change lanes in order to get on to the main link prior to the
end of the merging lane(s).
See below for an illustration of a one-lane merge into a three-lane freeway:
280 VISSIM 5.30-05 © PTV AG 2011