Although seemingly the same as four-wheel drive (4WD), the term all-wheel drive
(AWD) is generally used in reference to vehicles that are not designed to be
driven off-road or over harsh terrain.
AWD vehicles typically drive only two wheels most of the time and only engage
the other two wheels “on-demand” – in other words, when the road is slippery
and the on-board computer detects tyre slip.
‘Proper’ 4WD vehicles, on the other hand, can be manually switched to 4WD mode
and come with a low-range gear function, or transfer case, for off-road