Sources and method
Built for public reference.
Multiplex is built for public reference and curiosity. Route records combine seeded data for active and federally recognized routes with generated records for every possible number slot.
Mileage and year figures are rounded reference values organized from public route logs and encyclopedic route lists. They are not survey measurements.
Planning, engineering, or legal work should be verified against current records from the Federal Highway Administration, AASHTO, and the relevant state departments of transportation.