In the Renaissance Kingdoms, on any nodes that do not contain towns, it is possible for an individual or "group" (not an "armed group" or an "armed mob") to select the action "To steal from the travellers" as their work for the day (on the travel screen, under "Actions."
If you choose this action, one of the people you "meet on the road" that day (if you meet anyone on the road) will be attacked by you.
The outcome of the fight (if the victim selected the option to resist) is decided by a series of equations regarding detection and dice rolls and such, but a given fight is more likely to be won by the person or group with the higher fight coefficient:
From 0 to 49 Str -> fight coeff: 1
From 50 to 99 Str -> fight coeff: 2
From 100 to 149 Str -> fight coeff: 3
From 150 to 199 Str -> fight coeff: 4
From 200 to 255 Str -> fight coeff: 5
If the party that selected the robbery wins, they take all goods and money from the party they defeated (it is split among the group if the robbing party is plural). If the non-robber wins, no goods are exchanged. In either event, if the victor selected "I will not hesitate to kill my opponent" in their options (-1 coefficient if they don't), there is a chance that the loser will suffer a death.
There are almost always legal consequences for the robber if they do not manage to leave the county they performed it in before reports come to the attention of the prosecutor.