Turning a modern mechanized division loose means supplying those troops at the rate of 20-30 gallons of fuel per man per day. As the 3rd Infantry Division moves from Kuwait to Baghdad, some 20,000 troops are involved. That's a need for some 200 tanker loads of fuel per day. Initially, the vehicles carry enough fuel to go 200-300 kilometers on internal fuel. But you don't want your vehicles to run until their tanks are dry, so at least once a day, you try to top everyone off. The route of the 3rd Infantry Division covers about 700 kilometers of road. In addition to fuel, you need about a 100-200 pounds of other supplies per man per day (mostly ammo, but also batteries, food and the like.) Once inside Baghdad, and no longer moving all the time, the fuel requirement come way down. But on the march, the advancing combat brigades are tethered by convoys of fuel trucks going back and forth to the supply bases in Kuwait.