Awesome. Good luck to 'em.
The linear city concept has been proposed by many geniuses over the years, in many creative ways. For example, Le Corbusier's Plan Obus for Algiers (a viaduct city fourteen stories tall and God-knows-how-many lanes wide winding along the Mediterranean coast), or Cedric Price's Potteries Thinkbelt (a mobile university with portable capsule housing and modular classrooms-on-rails strung along a hundred square miles of disused rail corridors in the English Midlands). Often proposed, but never built. Will the Saudis finally make the dream come true?