chapter  10
54 Pages


Road networks comprise links and nodes. The nodes are the points at which links (highways, roads or streets) cross. The three general types of crossings are at-grade, grade separations without ramps and grade separations with ramps – otherwise interchanges. They are referred to in most countries as intersections, differentiating between three-legged, four-legged and multi-legged intersections although, in the United Kingdom, reference is to three-, four-and multi-armed junctions. In this book, reference is to ‘intersections’ and ‘legs’.