The freeway begins southwest Richland at a trumpet interchange with I-82 and US 12, located near Badger Mountain. The concurrent I-182 and US 12 travel northeast through Goose Gap in the Horse Heaven Hills and enters Richland, where it passes through housing subdivisions and a retail district surrounding the Queensgate Drive interchange. The freeway then crosses over the Yakima River and intersects SR 240, beginning a short concurrency along the southern outskirts of central Richland. SR 240 splits from the freeway at the following junction, a cloverstack interchange with George Washington Way, and travels southeast towards Kennewick. I-182 and US 12 continue across the Columbia River on the Interstate 182 Bridge, formally the Lee-Volpentest Bridges, which carry six freeway lanes and a section of the Sacagawea Heritage Trail on twin concrete spans. The freeway continues northeast into Franklin County and the city limits of Pasco. I-182 enters Pasco and turns 90 degrees southeast towards the city center after intersections with Broadmoor Boulevard and Road 68 at Gesa Stadium. The freeway intersects US 395 in a trumpet interchange, beginning a third concurrency, and 20th Avenue in a partial cloverleaf interchange near Columbia Basin College and the Tri-Cities Airport, utilizing an eastbound collector-distributor lane. I-182 continues east, forming the northern boundary of downtown Pasco, intersecting 4th Avenue before crossing over a BNSF-owned railyard. The freeway reaches a cloverleaf interchange with SR 397, where US 395 splits off to travel north towards Spokane. I-182 ends southeast of the interchange, while the roadway continues southeastward towards Burbank and Walla Walla as US 12. I-182 is defined by the Washington State Legislature as SR 182, part of the Revised Code of Washington as §. As a component of the Interstate Highway System, the highway is listed as part of the National Highway System for its entire length, classifying it as important to the national economy, defense, and mobility. The Washington State Department of Transportation maintains the freeway and designates the corridor as a Highway of Statewide Significance, which includes highways that connect major communities in the state of Washington. WSDOT also conducts an annual series of surveys on its highways in the state to measure traffic volume, which is expressed in terms of annual average daily traffic, a measure of traffic volume for any average day of the year. WSDOT calculated that the busiest section of I-182 is between its interchange with SR 240 and the Interstate 182 Bridge in Richland, where approximately 60,000 vehicles used the freeway on average each day in 2013; in contrast, the lowest traffic level on I-182 was 8,900 vehicles at its western terminus with I-82.
History
As part of Washington's first connected state highway system, the Washington State Legislature designated the Inland Empire Highway between Ellensburg and Laurier in 1913. The State Highway Board selected a route that would connect the main cities of Eastern Washington and the Inland Empire, which were Ellensburg, Yakima, the Tri-Cities, Colfax, and Spokane. In 1923, by which time the entire road had been improved, the highway became State Road 3, but retained its name. By that time, all of the route of Interstate 182 became a part of US 410 and US 395; both were established in 1926. When I-82 was approved in 1956, the Tri-Cities wanted an Interstate, since Interstate 82 bypassed the cities. Interstate 182 was the solution and created a connection to the Tri-Cities. Legally, I-182 is defined by the Revised Code of Washington § 47.17.372.
