Since the 1950's, heavy gage wire mesh has been used along North American highways to control rockfall on actively eroding slopes. More robust fabrics, such as cable nets, have more recently been introduced to improve the capacity of these rockfall protection systems. To date, however, the design of these systems has been based primarily on empirical methods, engineering judgment, and experience. This report summarizes research that characterized existing performance, tested critical system components, back-analyzed system failures, evaluated typical loading conditions, and developed analytical models to refine engineering design of these systems. Finally, guidelines were developed to support the design of these systems for a variety of loading conditions. Specifically, the report provides design guidance on site suitability, characterizing external loads, fabric selection, anchorage requirements, and system detailing.