The Armored Personnel Carrier (APC) transports and protects up to five troops heading to and from battle locations. Its heavy armor, fast speed, and long sight range make it an ideal scouting unit. It is also useful for crushing infantry - Tiberian Dawn manual(src)
Issued to GDI in the early stages of the First Tiberium War, the armored personnel carrier is a fully tracked armored vehicle designed for transporting soldiers through active warzones. Though lightly armed, the APC is durable and fast thanks to the alloys used for its armored plating, allowing it to penetrate enemy defensive lines and deliver its occupants where they are needed.
The APC is a step up from the Humvee. Although it mounts the same machine gun, it is far more durable, just as fast, and is capable of crushing infantry. It gives GDI forces an effective counter to enemy infantry: The APC has to stop and turn in order to use its machine gun, but infantry can simply be ground beneath its armored tracks. In fact, some scenarios rely on effective use of APCs to nullify Nod's advantage in numbers.
Notably, while engineer rushes can be very effective, the APC is very vulnerable to Obelisks of Light, which can destroy it in two shots, dumping its occupants on the battlefield unprotected.