The primary focus on the topic of fuel efficiency usually has the general public in mind. Looking for ways to save you, the consumer, money at the pump by making you go there less. It is not just the consumer concerned; fuel savings is a key issue for military.
The Army invests a huge sum of money into fuel-efficient technologies. The majority of which is focused on Future Combat Systems (FCS). The FCS is the Army’s program to modernize the military. The FCS is a $160 billion project; its goal is to create new manned and unmanned vehicles that are linked by a huge, fast, and flexible battlefield network.
Huge costs on the Army are their fuel costs. The U.S. military is the single largest consumer of oil in the world, consuming around 340,000 barrels per day ( With a fleet of:

The Buffalo Mine Protected Vehicle gets around 3.5 mpg

The Humvee gets less than 11 mpg

The Cougar Armored Vehicle gets about 9 mpg

The main battle tank of the U.S. is the M1 Abrams and it doesn't even get 1 mpg. It comes in around 0.6 mpg

The Army also employs other vehicles (Howitzer, Amphibious Assault, etc.) that come in at under 2 mpg. It is no wonder that the Army is looking to find ways to cut costs. The new vehicles that the army will be implementing will not get anywhere near what domestic vehicles get. The new tank that is to replace the M1 Abrams is going to get under 2 mpg, but that is still 3 times better than what is currently available. Other vehicles, like the Humvee, stand to see much better improvements. While still not ideal it is encouraging to see efforts being made.