Ultimate Interstates:Corridor 7
Ultimate Interstate 7 is an interstate highway corridor that would connect the Tri-Cities region in Washington State with Spokane, WA via I-90. the routing would travel along US-395 for most of its lenghth except for the southern section which would travel along US-12 to a new river crossing and new terrain route connecting to I-82 somewhere south of Pasco, WA. Much of the route would be upgraded as a result of the project from an at-grade expressway to a fully access controlled freeway facility with 2 lanes running in either direction.
Purpose and Need
The I-7 corridor is a critical corridor connecting northeastern Washington and the southwestern US. this would greatly reduce travel times and make a marked improvement to the Interstate System.
Alternate Routing
Another possible routing option is to keep the routing of I-7 east of the Columbia River connecting directly to I-84 instead of I-82 avoiding having to build a new river crossing. the routing would still have the intended interregional impact with the alternate routing with a lower cost due to not having to build the new river crossing. Additionally the south leg of I-7 would not serve Pasco directly and only serves to connect to I-84 and the rest of the interstate system negating the need for a new river crossing. Traffic from the I-390 route would access the Tri-Cities via SR-240 and existing I-182 which would both connect to the new I-7 corridor. This would also move through traffic away from the city center to the new southern leg of I-390.
Cascadia Corridor
The route could be designated as I-7 as part of a greater inland "Cascadia Corridor" that would connect to I-5 at US-97 in California. The route could also extend northward into Canada if need be as well providing another CANAM connection.
Auxiliary routes
This would open up the possibility for interstate spurs such as I-107 to Walla Walla or Clarkston, WA.
Plausibility
Interstate 7 is a logical designation for this highway due to its regional importance and connection to the greater interstate corridor. it is entirely likely that the section between Tri-Cities and I-90 will be upgraded to interstate standards. However the "Cascadia Corridor" will likely never be built.