I-205 busway

The transitway, which was physically separate from the parallel freeway lanes, was planned in the mid- and late 1970s as part of the final segment of I-205.

The transitway's right-of-way started in the median of I-205 near Portland International Airport and ran south to the junction of I-205 & I-84, where it continued through an underpass under the northbound lanes of I-205.

In the mid-1970s, Multnomah County officials negotiated a number of improvements to the proposed I-205 freeway with the Oregon Department of Transportation in order to win their support.

The Blue Line uses a short portion of the transitway between the Gateway station and Burnside Street, opened in 1986.

The portion south from Burnside (and beyond to the Clackamas Town Center) opened in September 2009 as the Green Line.

A MAX Green Line train at the north portal of one of the I-205 busway's two tunnels in 2015. Built in the late 1970s, the tunnels were first brought into use more than two decades later, by the MAX Red Line and later the Green Line.