In the 1920s, the Army built and tested a few trucks. The truck builders didn't do much. Then, in 1930, the Army built an test group of trucks. The standard fleet come in different sizes. They were strong and reliable, but only test trucks were built. The American truck builders said the Army was taking their business away. The Army had to stop building trucks. It was the Great Depression and the Army had very little money for trucks. Builders starting making test models in 1935. By 1939, more than 20 builders had made and improved test models.