The American D.B. of 1940 was inspired by the Pz.Ds which had just won a resounding victory in Europe. It consisted of a reconnaissance battalion, an armored brigade (with six battalions of light tanks and three of medium tanks, plus a battalion of 105 mm self-propelled vehicles a little later), an infantry regiment two battalions equipped with semi-tracked and armored T.T. vehicles, a towed 105 mm group, an engineer battalion and a service battalion, for a total of 108 medium tanks and 273 light tanks. br class='autobr' />The following organization was based on two armored regiments (with two battalions of medium tanks and one battalion of light tanks each), an infantry regiment with three battalions, and three groups of self-propelled of 105 mm, for a total of 375 tanks. In execution of General Chaffee's subsequent directives, the American armored division was reorganized on the basis of two inter-arms battle groups, which gave the large unit great flexibility and remarkable tactical efficiency.
The number of battle groups was then increased to three, while the light tank units were disbanded, which resulted in a decrease in the number of battalions, while the command units of the regiments were abolished. This new organization chart was applied to 14 of the 16 operational Armored Divisions in 1944-45. The other two retained the heavier structures inherited from 1942.