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. From here it ran east of the northbound I-205 lanes to just north of SE Division St. where it once again entered into a tunnel under both directions of I-205 and ran along the west side of the I-205 southbound lanes to SE Foster St. where it ended.
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. Among them was the transitway, a bike path and reconfigured interchanges. The transitway was intended to connect into the proposed Banfield Transitway at Gateway which originally was to have been a busway and would have run along I-84 to the Lloyd District and Downtown.
By the mid- to late-1970s, light rail became the selected transit mode in the Banfield corridor and opened in 1986 as Portland's first light rail line (now a portion of the MAX Blue Line). When light rail was selected over the busway option in the Banfield corridor, the fate of the proposed I-205 busway was sealed (as the busway made little sense without a downtown connection) although the corridor was, since the late 1970s, considered a potential future light rail line.
The Blue Line uses a short portion of the transitway between the Gateway station and Burnside Street opened in 1986. The portion of the route north from Gateway opened in September 2001 as the MAX Red Line. The portion south from Burnside (and beyond to the Clackamas Town Center) will become the MAX Green Line light rail line slated to open in late 2009.