Byway

From the White Wolf Wiki, the most complete White Wolf reference

A Byway is a safe and steady route through the Tempest in Wraith: The Oblivion. Byways are the most critical infrastructure in the Underworld, since without them, the only means to travel anywhere except the Shadowlands requires skill in Argos and no small degree of risk. Several natural Byways exist, the most important being the River of Death, however, the majority of Byways are artificial - the roads of the Stygian empire and the Imperial Highway of the Yellow Springs are both examples of constructed Byways.