Tunnel Inspection

National Tunnel Inspection Program

FHWA requires inspections of all tunnels carrying traffic on public roads to insure their safety and reliability. This program was initially mandated in the Moving Ahead for Progress in the 21st Century Act (MAP-21). The establishment of the requirements were detailed in the Federal Register in August 2015 defining the National Tunnel Inspection Standards (NTIS).

• Maintain an organization of performing the inspections, collect and submit the data, and insuring repairs
• Maintain an accurate inventory of tunnel data
• Perform regular inspections of tunnels, normally not to exceed a 24-month interval
• Use nationally certified tunnel inspector personnel
• Calculate each tunnel's safe vehicular load-carrying capacity in accordance with the Sections 6 or 8 of the AASHTO Manual for Bridge Evaluation (MBE).
• Notify FHWA within 24 hours of any critical findings and the activities taken, underway, or planned to monitor the critical finding. Provide FHWA regular updates or as requested on the states of each critical findings until it is resolved.

Washington State Tunnels

The data provided below for the State of Washington is based on the National Tunnel Inventory (NTI) data that was submitted into the Federal database in March 2021 and released as of June 15, 2021. In Washington State, there are 61 tunnels carrying public roads that are subject to the Federal inspection requirements. Of those structures, 51 tunnels are State owned, 3 tunnels are owned by local agencies, 1 tunnel is owned by a railroad, and 6 tunnels are owned by the National Park Service (NPS).