Between 1922 and 1929, the American economy experienced a massive boom which saw the average income expand by 27% and the annual wealth produced by 40%. These years became known as the Roaring Twenties.

             The boom happened for a number of reasons such as the introduction of assembly lines, the start of radio, and an increased demand for radio sets, and increased share prices.

             The single factor which contributed more to the boom than anything was the motor industry. Between 1918 and 1925, millions of jobs were created across America in car production. The car industry also boosted the petrol industry and 7 billion gallons of petrol was used up in people"s cars every year. More roads had to be built, so the road building industry prospered. The leisure business profited because Americans could now afford to travel "beyond their back yards" to be entertained. Petrol stations (or 'gas stations"), roadside 'Motels" and roadside restaurants sprang up everywhere and millions more were employed to work in these. The US film industry took off, because American"s could now travel to the cinema in their cars, and by the 1920s, 100 million cinema tickets were being sold every week. The cinema also featured cars, which boosted sales worldwide. Industries such as the rubber industries, the glass industry and the steel industry also prospered. For example car making used up 20% of America"s steel, 80% of her rubber, 75% of her plate glass and 65% of her leather.

             The introduction of Assembly lines, where production was broken down into separate jobs by each worker who did one job again and again and then passed the item on to the next stage of production. Because goods can be produced faster, with less manpower and using up less space and less electricity with this method, goods became much cheaper to produce. For example, the price of a Ford Model T fell from $850 to $295 by 1926.