1970s highway plans
Alternative 4 in the 1970's T-2000 plan called for extending the WEP (it wasn't called that yet) along the train tracks through Whiteaker. The WEP's "purpose and need" states the highway is needed to connect Oregon 126 with Interstate 105 -- and therefore would require some sort of additional connector (extension?) of I-105. See the plans for the 6th / 7th Freeway.