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 average annual daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that the busiest section of SR 3 was between SR 16 in Gorst and SR 304 in Navy Yard City, serving 69,000 vehicles, while the least busiest section was southwest of Allyn-Grapeview at an intersection with Grapeview Loop Road, serving 6,600 vehicles. SR 3 is designated as a STRAHNET corridor within National Highway System, connecting Naval Base Kitsap to the state highway system between Gorst and Bangor, while the rest of the highway is part of the system, which includes roadways important to the national economy, defense, and mobility. WSDOT designates the entire route of SR 3 as a Highway of Statewide Significance, which includes highways that connect major communities in the state of Washington.