Is more than 2WD necessary?

All-Wheel Drive – As the name implies, all-wheel drive (AWD) configurations feed power to the four wheels on a vehicle, which requires more parts in the drivetrain, but provides maximum forward traction, especially handy to have in slippery conditions. Most AWD systems deliver power primarily to just a single set of wheels–either front or rear–until slippage is detected to lead to all four wheels receive power. AWD systems are particularly helpful in rapidly changing conditions or when driving on a road with intermittent ice and snow. AWD is commonly used on most car-based SUVs, as well as many minivans and cars.
Four-wheel drive – Albeit four-wheel drive (4WD) and AWD are designations are frequently used interchangeably, a difference exists: Generally, 4WD is optimized for off-road and rugged driving situations. Think vehicles like Jeeps and heavy-duty pickup trucks. Most 4WD systems have low and high gear ranges, the former you can make use of to increase low-speed climbing power while driving off-road.
Modern 4WD systems are either full-time, which means they stay engaged when driving; automatic, where the vehicle automatically changes between four- and two-wheel-drive mode; and part-time, which require a driver to manually shift between four- and two-wheel drive.
Aside from those serious about driving off-road, many drivers are never close to needing the capability that 4WD systems provide above and beyond AWD systems. That is why you see them mostly on heavy duty or off-road vehicles. Read More: AutosModel.com