These are two of Portland's most famous "ghost ramps".

Both of these ramps were to connect the Marquam bridge traffic to the never to be completed Mt. Hood freeway. The Marquam was completed in 1966 and was planned with the Mount Hood as the next step. The top two northbound lanes were to connect to the Mt. Hood. The lower ramp (exit 300A) was to connect to the eastbound Mt. Hood. In 1992, the Marquam was modified and eliminated the "ghost ramps" on the top level. The ramp below still remains.

What is a "ghost ramp"? A partially or fully constructed freeway ramp that was never used or closed.