Much of the Transportation subseries relates to Interstate 90. Construction of the final portion of I-90 over Lake Washington and through the Mount Baker neighborhood was put on hold by the courts after a group of citizens sued to stop the project. The court lifted its injunction in 1979 and the freeway was eventually completed. Another major topic is the West Seattle Bridge, where materials document the discussions about location and design and include a fair amount of citizen input. Files also cover the Jefferson bus barn, the monorail and mass transit, and the First Avenue South Bridge.