Every year the Washington State Department of Transportation (WSDOT) conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of annual average daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that between 2,000 and 2,400 vehicles per day used the highway, mostly at Coles Corner.[6]
History
A road connecting a Great Northern rail line to Lake Wenatchee was built by 1904,[7] and was designated as part of SSH 15C in 1937, traveling from PSH 15, concurrent with US 10,[8] at Coles Corner to PSH 15 and US 10 in Leavenworth via Lake Wenatchee State Park.[9][10] SSH 15D was also established in 1937,[9] traveling west from SSH 15C to Telma.[10] US 10 was moved south in the 1940s and replaced by US 10 Alternate,[11] which was later replaced by US 2 in 1946.[12] After the 1964 highway renumbering, SSH 15C was split between SR 207 and SR 209, with SSH 15D becoming an extension of SR 207.[2][13][14] SR 209 and a 5.99-mile-long (9.64 km) segment of SR 207 from Chiwawa Loop Road to Telma were removed from the state highway system in 1991,[2][4][15] and no major revisions to the highway have occurred since 1991.[16]
^ abWashington State Legislature (March 18, 1937). "Chapter 207: Classification of Public Highways". Session Laws of the State of Washington (1937 ed.). Olympia, Washington: Washington State Legislature. pp. 1010–1011. Retrieved January 21, 2013.
^ abWeatchee, 1948(JPG) (Map). 1:250,000. United States Geological Survey. 1948. Retrieved January 21, 2013.