The engagement of four-wheel drive (4WD) in a vehicle refers to the activation of a drivetrain system that provides power to all four wheels simultaneously. This contrasts with two-wheel drive (2WD) systems, which deliver power to only two wheels. Operating a vehicle in this mode enhances traction and control, particularly in challenging terrains and adverse weather conditions. An example of its use is when traversing a snow-covered road where increased grip is necessary to maintain forward momentum.
Utilizing a four-wheel drive system offers significant advantages in situations demanding heightened traction, such as off-road driving, navigating slippery surfaces, or ascending steep inclines. The increased power distribution improves stability and minimizes the risk of wheel slippage. Historically, 4WD systems were primarily found in utility vehicles and trucks designed for rugged use. However, advancements in automotive technology have led to the integration of 4WD in a broader range of vehicles, including SUVs and even some passenger cars.