century, particularly before the popularization of the automobile, railroads became dominant and largely supplanted the state's roadways as means of long-distance transportation. 20th century The Wisconsin constitution had to be changed in order for the state to be able to pay for its new highway projects. After approval by the state legislators, an amendment was passed allowing Wisconsin to use funds for highway construction, in 1908. In 1911, the Wisconsin Highway Commission was established as a central planning organization for the state's first motorized roadways. Countless "auto trails" were created in the mid-1910s. Many of these used inefficient routes and were inconsistent. In 1917, the Commission began developing a standardized numbering system in response to the proliferation of privately marked highway systems. The state legislature made this practice illegal in 1917, in a law that also provided for the creation and marking of a state trunk highway system, that would be required to provide access to every county seat and all towns with a population over 5,000 and was limited to a total length of . The first signposts were erected in May 1918. Thus, Wisconsin became the first state in the country to officially mark and number its state highways. This highway system was quickly copied by Michigan, and eventually to all other states. Wisconsin's first distinctive route marker (required by the 1917 legislation) was an inverted triangle. The triangle by itself was found in practice not to use space efficiently. The distinctive route marker was eventually redesigned and codified to be the union of an inverted triangle and a rounded rectangle in 1933; this shape remains in use today. In 1925, a state highway fund was established, including a two-cent-per-gallon fuel tax. In 1929, the original highway commission was abolished and replaced with a new commission. The commission had 375 employees by 1930. The first U.S. Numbered Highways were established in Wisconsin in 1926, in many cases taking the place of highways the state had already established. As a result, the goals of the state highway system were expanded, aiming to reach every town with a population over 2,500 and relaxing its previous upper bound on network length. During the Great Depression, the state of Wisconsin launched a large number of public works projects in accordance with the New Deal, which led to massive expansions of the state system. By the 1940s, the system reached , approximately its