All wheel drive (AWD) is a drivetrain configuration engineered to direct power to all four wheels of a car simultaneously. Most cars on the market today are front wheel drive, meaning that the front two wheels receive all of the power, though sports cars and trucks, remain, for the most part, rear-wheel-drive. There is some confusion over the differences of AWD versus the traditional four-wheel-drive systems, but just remember that, although both systems utilize a center differential, 4WD systems can be engaged and dis-engaged at will, while AWD systems are always on, all the time. All-wheel-drive provides serious advantages over front or rear-wheel-drive systems in terms of traction, and is the preferred drivetrain in snowy parts of America and the rest of the world. Most AWD systems adjust the power distribution (which wheels get how much power) depending on the situation, but for every day driving the usual delegation is 60% of the power to the front wheels and the remaining 40% to the rear wheels. A drawback of the AWD system is that it requires even tire wear, meaning that if you have to replace a single tire due to a flat or other damage, all four tires must be replaced. Overall, though, it remains a reliable and powerful system and can be found on cars such as the Volvo S60, Mitsubishi Lancer Evolution, Subaru Forrester, and Dodge Journey.