A Seattle group opposes the premise of a rebuilt viaduct freeway, a replacement tunnel or a combination of improved surface streets and transit. It says those options don't solve any regional transportation needs.
Instead, the group suggests a system of transit lines that echos the role of the now-defunct Seattle Monorail.
The group, headed proposes a new tunnel for cars and transit under downtown Seattle, with lines leading to West Seattle, the north end and the suburbs. Unlike the monorail, which competed with under-construction light rail line, this plan, called Sea-REX, supposedly would complement other transit modes.
The group tries to make the case for more transit infrastructure by juxtaposing other cities' transit lines on a map of Seattle, located on this web site. It notes that even with the light rail line and Sounder commuter trains, Seattle's system will be far from regional.