When NAT translations (xlates) and rules do not determine the egress interface, the system uses the routing table to determine the path for a packet.
Routes in the routing table include a metric called “administrative distance” that provides a relative priority to a given route. If a packet matches more than one route entry, the one with the lowest distance is used. Directly connected networks (those defined on an interface) have the distance 0, so they are always preferred. Static routes have a default distance of 1, but you can create them with any distance between 1-254.
Routes that identify a specific destination take precedence over the default route (the route whose destination is 0.0.0.0/0 or ::/0).