strongest and best-developed market in bike design, Dutch framemakers either copied them or imported them from England. In 1895, 85 percent of all bikes bought in the Netherlands were from Britain; the vestiges of that influence can still be seen in the solid, gentlemanly shape of a traditional Dutch bike even now. Though the ladies' version of the roadster largely fell out of fashion in England and many other Western nations as the 20th century progressed, it remains popular in the Netherlands; this is why some people refer to bicycles of this design as Dutch bikes. In Dutch the name of these bicycles is Omafiets ("grandma's bike"). Popularity in Europe, decline in US Cycling steadily became more important in Europe over the first half of the twentieth century, but it dropped off dramatically in the United States between 1900 and 1910. Automobiles became the preferred means of transportation. Over the 1920s, bicycles gradually became considered children's toys, and by 1940 most bicycles in the United States were made for children. In Europe cycling remained an adult activity, and bicycle racing, commuting, and "cyclotouring" were all popular activities. In addition, specialist bicycles for children appeared before 1916. From the early 20th century until after World War II, the roadster constituted most adult bicycles sold in the United Kingdom and in many parts of the British Empire. For many years after the advent of the motorcycle and automobile, they remained a primary means of adult transport. Major manufacturers in England were Raleigh and BSA, though Carlton, Phillips, Triumph, Rudge-Whitworth, Hercules, and Elswick Hopper also made them. Technical innovations Bicycles continued to evolve to suit the varied needs of riders. The derailleur developed in France between 1900 and 1910 among cyclotourists, and was improved over time. Only in the 1930s did European racing organizations allow racers to use gearing; until then they were forced to use a two-speed bicycle. The rear wheel had a sprocket on either side of the hub. To change gears, the rider had to stop, remove the wheel, flip it around, and remount the wheel. When racers were allowed to use derailleurs, racing times immediately dropped. World War II Although multiple-speed bicycles were widely known by this time, most or all military bicycles used in the Second World War were single-speed. Bicycles were used by paratroopers during the war to help them with transportation, creating the term "bomber bikes"