From the release:
Your players have set out on a long journey over the lawless land between cities and villages. During these times of war, petty rulers have their army stretched. They must defend their strongholds but also march out to contain their enemies. This has left the road to chaos. Bandits and worse take what they can, from those who are not swift enough to avoid them, or cannot hold their possessions through force of arms.
The road is a place where the curtain of civilisation is torn apart, and the stage is given to the beasts and killers amongst men. Yet there are those who take the gamble on barren paths; facing starvation, robbery and the elements, in the hope of gaining a reprieve from poverty or the confinement of besieged cities.
100 Travel Encounters - Tales for Dark Roads can be used as an idea-generator for whenever PCs begin a perilous overland journey.