This article is considered accurate for the current version (1.54) of the game.
Fitted with all-terrain treads, the Highlander brings significant all-terrain mobility and performs especially well in snowy and mountainous environments.
— In-game description
The O'Brien V.121 Highlander (also known as a Tracked Armored Car or a TAC) is a Warden anti-infantry Armored Car with improved off-road mobility and equipped with a twin short-barreled 7.92mm machine gun.
The O'Brien V.121 Highlander has 900 HP and is disabled under 30% health. It has "Light Armor" resistance: it can soak small arms fire and shrapnel, and it is immune to Flamethrowers. But it won't last long when faced with 12.7mm machine guns, heavy explosives, or anti-tank weaponry. It has Tank Armor. With it, in best case scenario, penetrating projectiles only have a 85% chance of penetrating and doing damage. That chance goes up quickly if the armor is worn or if it is shot from up close, or on the side or rear from a direct angle, or with ammo that has penetration bonuses. It takes 115 Basic Materials to fully repair it from 1% to 100% health with a Hammer. Its health and Tank Armor can be instantly repaired at a Garage for 100 Basic Materials.
The O'Brien V.121 Highlander is a lightly armored car solely designed to combat infantry. In terms of mobility, it has decent on-road speed and slightly worse off-road speed, which gives it greater flexibility in where it can effectively fight (in addition to its movement not being affected by snow storms). Along with its slow-turning turret, it is better to stay on roads so the crew can react faster if they're being flanked (though this is slightly mitigated). Additionally, due to its low health, a single anti-tank mine will nearly destroy it.
Due to the vehicle equipped with 7.92mm ammunition (a light kinetic ammo type), it cannot damage defensive structures and struggles to suppress them due to its bad accuracy. As such, it shouldn't be used to push defenses, especially those with active AI. It is better suited to attacking enemy infantry out in the open or behind certain defenses (such as Trenches, Sandbags, etc.), as well as protecting friendly infantry from enemy forces by suppressing them or killing them.
Similar to all armored cars, as soon as heavier anti-armor weapons become more common, (such as anti-tank rifles) the O'Brien V.121 Highlander quickly becomes obsolete on the front line, as they will quickly be destroyed, as longer ranged weapons prevent the crew from reacting fast enough before being destroyed.