Armoured personnel carriers

An armoured personnel carrier (APC) is a type of armoured fighting vehicle (AFV) designed to transport infantry to the battlefield. APCs are colloquially referred to as 'battle taxis' or 'battle buses', among other things. Armoured personnel carriers are distinguished from infantry fighting vehicles by the weaponry they carry.

The Treaty on Conventional Armed Forces in Europe defines them as "an armoured combat vehicle which is designed and equipped to transport a combat infantry squad and which, as a rule, is armed with an integral or organic weapon of less than 20 millimetres calibre." By convention, they are not intended to take part in direct-fire battle, but are armed for self-defence and armoured to provide protection from shrapnel and small arms fire.

Examples include the American M113, the French VAB, the Dutch-German GTK Boxer and the Soviet BTR.

The genesis of the armoured personnel carrier was on the Western Front of World War I. In the later stage of the war, Allied tanks could break through enemy lines, but the infantry following — who were needed to consolidate the gains — still faced small arms and artillery fire. Without infantry support, the tanks were isolated and more easily destroyed. In response, the British experimented with carrying machine-gun crews in the Mark V* tank, but it was found that the conditions inside the tanks rendered the men unfit for combat. Britain therefore designed the first purpose built armoured troop transport, the Mark IX, but the war ended before it could be put to use.

...
Wikipedia