(Oregon/Washington border to Exit 1; MP 0.00-1.00, 1.00 miles)
Interstate 82 was created under the National System of Interstate and Defense Highways Act of 1956 along with several other freeways in Oregon. However, the freeway (the last of Oregon's original planned routes to be built) wasn't built until the early 1980's, as the route in Washington wasn't definite yet, and remained that way for awhile. It seemed as if Washington's plan kept changing every few years; a 1965 Chevron map shows the "Satus Alignment," which left the Yakima River around Satus before heading south over the Patterson Ridge before stopping around Plymouth (just across the Columbia from Umatilla, Oregon); a 1968 Texaco map shows the "Prosser Alignment," which stayed with the Yakima a little longer to Prosser, then traversing the Patterson Ridge and stopping at Plymouth; a 1970 Enco map shows the Satus Alignment; finally, a 1972 Arco Map shows the Prosser Alignment.
Neither of these alignments were ultimately used because of two factors: A population boom and the lobbying that resulted. Because of the amount of time it took to build I-82 (I-82 was built only around Yakima in 1968 and then from Ellensburg to South Yakima in 1972), the Tri-Cities of Washington, Kennewick, Pasco, and Richland, were able to grow into a major metropolitan area and lobbied for a closer connection to the Interstate highway system. Thus, I-82 was shifted even further east to skirt the Tri-Cities, and a spur route (I-182) was built along US-12's path into the Tri-Cities. It is unclear if a spur or loop route was planned in the Tri-Cities before the shifted alignment, but a small freeway, WA-240, was built before 1965. In any event, with I-82's route planned in Washington, construction began, culminating with the opening of the highway in 1987. US-395, which originally had multiplexed with US-730 from Umatilla, OR (and previously from Cold Springs, OR) to Jct US-12 near Wallula, WA, then multiplexing with US-12 until Pasco, was realigned with I-82 for about 20 miles beginning from Exit 1 in Oregon across to Washington's Exit 113.
The odd thing is that this route runs more North-South than it does East-West, and the I-82 number is troubling, as it is above I-84 and thus violating the Interstate numbering rules. Originally, however, it didn't technically; I-84 until 1980 was called I-80N, as it connects with I-80 proper in Utah. When AASHTO decreed that split and suffixed routes were no longer allowed, I-80N became I-84, therefore creating an anomaly in the numbering. My fix would be to number I-82 as I-86, and then connect it to I-86 in Idaho, therefore utilizing a Boise-Seattle connection and fixing the numbering glitch.
Additionally, according to AARoads.com, I-82's alignment was proposed to start in Tacoma, WA rather than Ellensburg, then travel over the Naches Pass of the Cascades directly to Yakima. While this proposal has been dead since the 1960s, the desire to build some kind of highway over Naches Pass survives as WA-168, an unbuilt but planned highway that would connect to WA-410 and provide the direct Tacoma-Yakima connection I-82 would've done if it was routed this way. Also, Oregon has been batting around the idea of extending I-82 further south along a new freeway. Three routes have been proposed:
Budget crises aside, while I'd love to see a new Interstate built in Oregon, I doubt that any one of these routes is feasible enough to get major support. The John Day alignment, while the most reasonable alignment with respect to I-82's current routing, also seems the most useless; I don't see much of a need for an Interstate through John Day, Burns, or Lakeview, and the southern terminus is questionable. It could connect with I-80 in Reno, Nevada or be routed over the mountains to I-80 or I-5 near Sacramento, but is a Reno/Sacramento to Tri-Cities connector necessary? The Madras route seems decently feasible because it at least places the route through Central Oregon, a fast-growing area. However, a road built from Hermiston to Madras would seem a little out of place and would be too close to I-84 to yield decent results; plus, the way that I-82 is aligned already, it would look a little odd to have a highway shifted 60 miles to the east and then 60 miles back to the west. The Prineville alignment seems the most feasible of them all; it would act like a true north-south route, gradually shifting the 60 miles west that would be so dramatic with the Madras Route. It would utilize the recently built Bend Parkway (which would be upgraded) and the freeway in Klamath Falls, and both cities have climbing populations. The problems would be environmental in nature and would also stem from people who live in Sunriver, a posh summer retreat just south of Bend. I have my own plan too, and you can see that plan here.