The logistical complexity behind the front line is visualised in this Third Army road traffic map of 1918.
Bold lines highlight the main roads for the use of motor vehicles and animals, whilst dotted lines denote single track roads, arrows giving the direction of travel. Exceptions are provided for officers and messengers, and animals are prohibited from being exercised on any roads.
Supply lines had failed during the Somme offensive of 1916, and a civilian, Sir Eric Geddes, was drafted in to improve British Expeditionary Force transport arrangements. By 1918 an efficient system of moving supplies, men and ammunition as quickly as possible to the front, and casualties and information away from it, had developed.
At the time of this map, the German Spring Offensive struck at the front in the bottom right corner of the map. In such circumstances the speed of logistics could be the difference between success and failure.