circular.add.xml

<?xml version="1.0" encoding="UTF-8"?>
<additional xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/additional_file.xsd">
    <route id="routeRight" edges="bottom right top left"/>
    <route id="routeLeft" edges="top left bottom right"/>
    <route id="routeTop" edges="top left bottom right"/>
    <route id="routeBottom" edges="bottom right top left"/>
    <rerouter id="rerouterBottom" edges="bottom">
        <interval begin="0" end="100000">
            <routeProbReroute id="routeRight" />
        </interval>
    </rerouter>
    <rerouter id="rerouterTop" edges="top">
        <interval begin="0" end="100000">
            <routeProbReroute id="routeLeft" />
        </interval>
    </rerouter>
</additional>