In this tutorial we will build a simple circular net with netedit and use rerouters to make vehicles drive in circles. All definition files can also be found in the <SUMO_HOME>/docs/tutorial/circles directory.
Build a network#
First open netedit and create edges to form a
closed loop. To do that press
Ctrl-N to create a new network and then
e to enter the edge editing mode. Now create a closed loop of
edges (you might consider to check 'chain' just right from the edit-mode
selection, see figure).
The result should look more or less like shown in the figure. The
important thing is the circular shape. Now save the network somewhere
Ctrl-Shift-S) in an empty directory (we will refer to that place by
baseDir). As name for the created net-file type in
Create vehicles and run SUMO#
baseDir create two empty text-files, call them
circles.sumocfg. These files will define our
vehicles and the run configuration.
First, we edit
circles.rou.xml and define a vehicle flow of five
standard passenger cars. The file contents should look like this:
<routes> <vType id="car" type="passenger" length="5" accel="3.5" decel="2.2" sigma="1.0"/> <flow id="carflow" type="car" beg="0" end="0" number="5"/> </routes>
To use the route-file and the generated net-file with SUMO, we edit the
circles.sumocfg to tell SUMO where it finds vehicle
and net definitions:
<configuration> <input> <net-file value="circles.net.xml"/> <route-files value="circles.rou.xml"/> </input> </configuration>
First attempt to run the simulation
Now let us try to start sumo with the config that we have just created.
To do so either double-click on the configuration-file
(under Windows, if your installation was done with default settings) or
change to the
baseDir in a terminal and start sumo (with graphical
user interface) there by typing
sumo -c circles.sumocfg. (If this does
not start sumo, you might have to add the SUMO/bin directory to your
Did it work? No.
Let us have a look at the Message Window at the bottom of the GUI to endeavor what went wrong (by the way: the Message Window is often a very useful resource for information for setting up a simulation take a look at it first, if you run into problems).
Error: The route for flow 'carflow' has no edges. This means
that SUMO does not know from where to where the vehicles of the flow we
circles.rou.xml should take. To do this, we need to add
from, and provide corresponding edge-ids to the
Renaming an edge in netedit
The edge-ids can be inspected and modified in netedit: open your
circles.net.xml and press
i to enter the inspect-mode.
Left-click on an arbitrary edge and rename it to
edge1. Left-click on
a different edge and rename it to
edge2. Then save your network
Now we add the from-edge and the to-edge to the flow in
... <flow id="carflow" type="car" beg="0" end="0" number="5" from="edge1" to="edge2"/> ...
Running five cars on the circular net
Let's try to run SUMO again. The window should now show the network you have created before in netedit and you can start the simulation by clicking on the play button () or the step button (). If you use , be sure to adjust the value for the animation delay time between consecutive simulation steps (the field labeled "Delay (ms):", see figure). Otherwise SUMO will run the simulation as fast as possible and you will probably see nothing happening at all. (Note that the the figure uses the style "real world" from the representation-dropdown-menu in the toolbar.)
The cars will drive from the beginning of edge1 to the end of edge2 and then leave the net (side remark: you can control the positions of departure and arrival by additional arguments to the flow, see Flow Definitions). The simulation ends when all vehicles have left the net.
Now let us make the vehicles drive in circles around the track again and again. To this end we will create a rerouter
Create a rerouter in netedit (full implementation pending!)
Editing rerouters in netedit is not implemented completely currently. Alter the tutorial correspondingly, when this has been done! (See netedit#Rerouter)
In the future the editing of rerouters will be possible in netedit. Up to now rerouters have to be added manually (see below). Here is what can be done in netedit so far: Open your network
circles.net and press
a to enter the additionals edit-mode. From the dropdown menu "Additional element" on the left select
rerouter and from "Edges" select
edge1 (see figure). Then click somewhere in the editing window to create the rerouter (the rerouter icon is placed at the location where you click, but the location has no further meaning). Repeat the steps to create a rerouter for
Since in SUMO the additional elements are not considered as elements of
the net, we have to specify them in a separate file (the
"additionals-file"). Create and open a file
circles.add.xml in the
baseDir and add the following xml-code (see Rerouter/Assigning a new
<additionals> <rerouter id="rerouter_0" edges="edge1"> <interval end="1e9"> <destProbReroute id="edge2"/> </interval> </rerouter> <rerouter id="rerouter_1" edges="edge2"> <interval end="1e9"> <destProbReroute id="edge1"/> </interval> </rerouter> </additionals>
Then we have to tell SUMO to include the rerouters into the simulation
by adding a line to the config
circles.sumocfg. Within the
add a child:
This will add two (destination-)rerouters to our network making the
vehicles go around the circle until the given end time (i.e., until one
hundred million seconds have passed). Effectively, each rerouter will
update the destination for each vehicle entering its edge (specified by
edge-attribute) and set it to the edge given in the
destProbReroute-element. So as soon as a vehicle enters
(its current destination), its destination will be updated to
and vice-versa, when entering
edge2 it will be rerouted towards
edge1, thus following a circular route.
Here are some simple ideas to extend this toy example:
A net with two loops
- add more lanes in netedit and another vehicle flow with faster cars to observe SUMO's overtaking behavior.
- add a scooter flow and use the Sublane Model to observe SUMO's sublane model.
- add another loop (see figure) and trigger the next loop for each vehicle by a probabilistic choice of the destination (Rerouter/Assigning a new Destination), observe merging at the location where both loops are connected.
- Insert more vehicles, lower the simulation time-step length and try to observe stop-and-go waves, experiment with different car-following models, color the vehicles by speed.
If you create solutions for the exercises post them on this page!
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