for any average day of the year. In 2012, WSDOT calculated that the busiest section of US 195 within Washington was in Hangman Valley before the I-90 interchange in Spokane, serving 19,000 vehicles, while the least busiest section was between Pullman and Colfax, serving 3,100 vehicles. The entire route of US 195 is designated as a Highway of Statewide Significance by WSDOT, which includes highways that connect major communities in the state of Washington. History The Inland Empire Highway was originally a collection of gravel county roads that have existed since 1898 in the Spokane area and 1905 in the Pullman area. These roads roughly followed an early territorial highway built in the 1870s between Colfax and Spokane. The highway was added to the state highway system in 1913, traveling within the Palouse region between Colfax and Spokane. The Second Division of the Eastern Route of the Inland Empire Highway was also established in 1913, traveling northwest from Sampson Trail Y at the Idaho–Washington state line to Pullman. The Idaho portion of US 195 became part of the North and South Highway in 1916 and was not numbered under Idaho's state highway system in 1953. The gap in the Second Division between Pullman and Colfax was named by Whitman County as a highway of importance the following year and was not built until 1925 as part of State Road 3. State Road 23, connecting Spokane to Newport, was designated in 1915 before it was renamed to the Pend O'Reille Highway and renumbered to State Road 6 in 1923. The Inland Empire Highway was numbered as State Road 3 in 1923 and retained the designation as PSH 3 in 1937, while State Road 6 became PSH 6. The United States Highway System was established on November 11, 1926, during its adoption by the American Association of State Highway Officials (AASHO) and included US 195, traveling north from US 95 within Washington through Pullman and Spokane before ending at US 95 in Sandpoint, Idaho. The present four-lane divided highway along Hangman Creek in Spokane was constructed in 1939 as part of general improvements to Eastern Washington highways, relocating the route of the creek and a nearby Northern Pacific Railway line. The section of US 195 between Spokane and Sandpoint became co-signed with an extension of US 2 from Bonners Ferry, Idaho to Everett, Washington in 1946, and the highway was truncated to