An armored vehicle-launched bridge (avlb) [1] is a combat support vehicle, sometimes considered a subtype of military engineering vehicle, designed to assist armies in quickly dispersing (and primarily) across gap-type obstacles such as tanks and other armored combat vehicles across rivers. .

The AVLB is usually a tracked vehicle converted from a tank chassis to carry a folding metal bridge instead of a gun. The task of the AVLB is to allow armored or infantry units to cross craters, anti-tank ditches, swollen bridges, railroad crossings, canals, rivers and valleys [2]), when a river is too deep for vehicles to cross and there is no suitable bridge (or strong enough) , a major problem when transporting 60-ton tanks).

The bridge layer unfolds and launches its payload, providing a ready bridge over the obstacle in just a few minutes. Once the opening is in place, the AVLB vehicle leaves the bridge and pulls over to allow traffic to pass.

After all vehicles have passed, it crosses the bridge and reconnects to the bridge on the other side. It then retracts the opening, ready to move again. A similar procedure can be used to allow passage of small cliffs or similar obstacles. AVLBs can carry bridges 60 feet (19 meters) or longer.

By using a tank chassis, the bridge layer can cover the same terrain as main battle tanks, and providing armor allows them to move even in the face of enemy fire. But this is not a universal attribute: some exceptionally tough 6x6 or 8x8 truck chassis lend themselves to bridge layer applications.