The Red Line runs along Mill Plain Boulevard from downtown Vancouver to the eastern suburbs of the city; it opened on October 1, 2023.

[2][11] The Vine's stations consist of a 50-foot-long (15 m) platform that is raised for level boarding, and includes shelters and windscreens, ticket vending machines, real-time arrival signs.

[5] The Vine accepts the Hop Fastpass contactless smart card fare system, available throughout the Portland–Vancouver metropolitan area in coordination with TriMet and the Portland Streetcar.

[26][failed verification] The Southwest Washington Regional Transportation Council (RTC) began studying high-capacity transit for Vancouver and Clark County in 2008, and determined that bus rapid transit would be viable on four main corridors: Highway 99, Fourth Plain Boulevard, Interstate 205, and Mill Plain Boulevard.

[28] The Fourth Plain corridor had been served by local routes 4 and 44, the two busiest in the C-Tran system, which continued to northern Portland, Oregon.

[20] Design concepts for a Fourth Plan bus rapid transit service were presented in 2011 and 2012,[29] and a locally-preferred alternative was adopted by C-Tran, the Vancouver City Council, and RTC in 2012.

[30] On November 6, 2012, C-Tran placed a 0.1 percent sales tax increase on the general election ballot to fund a light rail extension from Portland to Downtown Vancouver via a new bridge, as well as operating costs of the Fourth Plain bus rapid transit project.

[39] Preliminary plans for the project was approved in 2019 and was followed by agreements with the city government on property acquisition and upgrading fiber optic lines along the corridor.

[40][41] The Mill Plain line, covering 9.9 miles (15.9 km) from the shared terminus at Turtle Place in Downtown Vancouver to Clark College's Columbia Tech Center near Southeast 192nd Avenue, will have 37 stations and is anticipated to cost $50 million.

[10][45] The Green Line is also planned to be extended east into Orchards and south along Northeast 162nd Avenue to Fisher's Landing Transit Center, a major regional hub near the Columbia River, by 2027.