As you're certainly aware, most cars these days have four wheels. So why do people make a distinction between all-wheel drive and four-wheel drive when driving ...

We describe how all-wheel drive (AWD) and four-wheel drive (4WD)—also known as 4x4—work, explain their similarities and differences, and how these two systems can be confused for one another.

If they aren’t AWD or 4WD, vehicles will use either front-wheel drive (FWD), in which the front wheels are powered by the engine, or rear-wheel drive (RWD), where power goes to the rear wheels.

AWD has snuck into 4WD vehicles as a setting, too. Some 4WD Fords, such as the F-150, include 4A (for “4WD Auto”) alongside the 4WD’s traditional 4L and 4H (4-High) modes.

The system utilizes electro-hydraulic AWD coupling to precisely activate the multi-plate clutch plate, constantly redistributing the amount of power transferred to the front and rear wheels.

So you only really ever use 4WD off-road, or in deep snow. Just to make matters as complicated as possible, some 4WD vehicles can also operate in AWD. Wes’ Land Rover Discovery is a great example.

"For the average driver, AWD is better – It automatically kicks in as needed," says Raynald Marchand, CSC general manager of programs, in an email. "4WD has to be manually selected, and it's ...

Part-time 4WD systems are often found in older off-road vehicles and trucks, such as the Suzuki Samurai, early Land Crusiers, and Jeeps. Wind-up causes transfer case components to snap or break.

However, not all 4WD systems feature this capability. Most have a limited slip differential system which senses which wheel is turning the slowest and sends power to it.

Basically, 4WD is of very little use on-road, so if you never plan to venture well off the pavement and into the rough stuff, you'll likely be better off with AWD. There are a couple of obscure on ...

Dynamax's AWD system on the new Kia Sportage has all of this, plus sensors that read the road ahead for ice, potholes, and flooding. See All 185 Photos ...