I'll through in my experiences with driving in snow and brakes in general. The HMMWV has a few things going against it for driving in snow on the roads. First are the stock tires. They work great in 3 feet of snow but on 1 inch they are nearly useless, they just aren't made for traction on the roads in snow.
Second, the brakes are a problem also. In a normal vehicle the rotors are directly attached to the wheel hubs and wheels. Of course you all know the HMMWV's are attached inboard at the differential. When you apply the brakes there is a lot of play before it applies the stopping power to the wheel. You see this merely coming to a stop at a red light and the vehicle kind of bounces back and forth after you stop. This is due to play in all the contact points like the inner CV, the outer CV and the reduction gears. Also the flex in the axle shaft itself (acts like a torsion bar). When applying the brakes in the snow, none of this helps.
Third, full time 4 wheel drive. You would think that would help and it does in 3 feet of snow. On the roads the lockers are not helping especially with cornering. In a regular open differential 1 tire is not applying power to the road and is merely there for the ride. It has better traction because it is not applying force and is less likely to slip in the snow. My HMMWV slips all the tires, especially on corners if you apply any power, when you need to traction the most.
IMO, you can only do so much to help these issues. A Mud and Snow or All Terrain tire verses a Mud knobby tire will help some. I've found it better in the snow with BFG 37x12.5x17's All Terrain tires than the stock off road mud tires. That said, it's like driving a giant rollerskate on ice. The more snow there is, the better it does. 1" of snow and you take your life in your hands on the road.
