 Transport infrastructure in France was severely disrupted by Allied bombers and the French Resistance, making it difficult for the Germans to bring up reinforcements and supplies.Much of the opening artillery barrage was off-target or not concentrated enough to have any impact, but the specialised armour worked well except on Omaha, providing close artillery support for the troops as they disembarked onto the beaches.The indecisiveness and overly complicated command structure of the German high command was also a factor in the Allied success.