'Red Ball' was the US system of one-way express truck routes through northern France from the English Channel ports to keep the Allied armies supplied with all necessities between the break-out achieved in 'Cobra' and the 16 November opening of Antwerp as a forward supply port (25 August/16 November 1944).

The French railway system having been effectively destroyed by Allied air power before the 'Overlord' invasion, with the express intention of denying the Germans the use of this transport system for the rapid movement of large numbers of men as well as substantial quantities of matériel and supplies, a truck-based system was the only means available to the Allies to move their own supplies forward. After the break-out and race to the Seine river there were 28 Allied divisions in the field, and for sustained offensive operations each division required between 700 and 750 tons of supplies of all types per day, for an overall daily total of about 20,000 tons.

At its peak, the 'Red Ball Express' operated some 5,960 vehicles and carried about 12,500 tons of supplies per day. In order to keep the supplies flowing without delay, two routes were created from Cherbourg to a forward logistics centre at Chartres. The northern route was used for the movement of supplies toward this centre, and the southern route for trucks returning empty to Cherbourg. No civilian traffic was allowed on either route. The route was used by convoys of no less than five trucks each escorted in front and behind by a Jeep. In reality it was not uncommon for individual trucks to move off as soon as they were loaded. The convoys were a primary target of the Luftwaffe, but by 1944 this service’s strength was so reduced that even these tempting and typically easy targets were rarely attacked. The biggest problems were maintenance, sleep, and the provision of a sufficient number of drivers.