Overview

• The Board of Audit reported 457 expressway segments crossing sediment-disaster warning zones where landslides could endanger traffic.
• It identified 290 locations that should have been designated as dangerous and flagged 2,876 more for detailed investigation, requesting NEXCO to expand selection efforts.
• Required records on external-risk sites were missing at 65% of management offices, and only one designated site had documented coordination with a municipality.
• Seventy-two management offices said they had not proactively initiated discussions with local governments, often assuming such oversight rested with municipalities.
• Risks were concentrated in NEXCO West with 269 unselected sites, led by the Himeji office with 82, and expressways saw 13 related damage cases in five years with roughly ¥12.4 billion in repair costs.