AWD systems, by nature, result in lower fuel economy than front-wheel-drive systems as there are simply more mechanical parts in play. It's an unfortunate aspect of physics. The trick to HTRAC is that it only turns on when needed, doing its best to save precious MPGs while driving. According to Hyundai, the "intelligent" aspect of the system deciphers up to 100 inputs from the wheels and sensors per second to ensure the best driving performance. It can also shift power between the front and rear wheels to better handle itself when driving conditions take a turn for the worse, or you get a little too zealous behind the wheel.
The HTRAC system can also be adjusted to fit whatever your driving habits are. If you don't ever drive in the rain, it can essentially be turned off with what Hyundai calls "Smart Mode" which directs all power to the front wheels, improving fuel economy. If you want to get a little more "dynamic" with your driving, there is "Sport Mode" evenly shifts power between the front and rear sets of wheels to improve handling.
The HTRAC system shines the most with the Genesis brand. In addition to offering AWD capabilities, HTRAC controls braking and works with the cars suspension system, to a degree. That not only ensures that all four wheels stay controllable, but the weight of the car itself isn't shifting around in a way that can compromise safe driving.