<P> Mass production improved productivity, which was a contributing factor to economic growth and the decline in work week hours, alongside other factors such as transportation infrastructures (canals, railroads and highways) and agricultural mechanization . These factors caused the typical work week to decline from 70 hours in the early 19th century to 60 hours late in the century, then to 50 hours in the early 20th century and finally to 40 hours in the mid-1930s . </P> <P> Mass production permitted great increases in total production . Using a European crafts system into the late 19th century it was difficult to meet demand for products such as sewing machines and animal powered mechanical harvesters . By the late 1920s many previously scarce goods were in good supply . One economist has argued that this constituted "overproduction" and contributed to high unemployment during the Great Depression . Say's law denies the possibility of general overproduction and for this reason classical economists deny that it had any role in the Great Depression . </P> <P> Mass production allowed the evolution of consumerism by lowering the unit cost of many goods used . </P>

Who pioneered the use of mass production for motor cars