This document reviews the use of fiber-modified stone matrix asphalt (SMA). SMA is a gap-graded asphalt concrete that uses fibers or polymers to prevent issues like drain-down. The document discusses how cellulose fibers, mineral fibers, and polymers can be used as stabilizing agents in SMA. It also summarizes several studies that have investigated using various fiber types like coir, jute, and pineapple fibers to modify SMA mixes and improve their mechanical properties and resistance to issues like rutting and drain-down. The optimal fiber content found in some studies was around 0.3-0.6% by weight of aggregates.