Critical Findings for Tunnel Functional Systems

In the National Tunnel Inspection Standards (NTIS) Final Rule, FHWA used the same definition of critical findings for highway tunnels as for highway bridges. The Tunnel Operations, Maintenance, Inspection, and Evaluation (TOMIE) Manual, incorporated into the regulation by reference, does not provide criteria for defining critical findings in functional systems. Tunnels have unique characteristics, which may include functional systems such as ventilation, lighting, drainage, fire/life safety/security, communications and signage for traffic management, and emergency evacuation. The intent of the NTIS and TOMIE Manual is that tunnel owners will define critical findings for each tunnel based on its unique characteristics. The operation of functional systems is highly variable between different tunnels. Some may have different modes of function for emergencies such as fires in tunnels, while others do not. Some have automatic or remote controls that can alter operation modes in response to changing conditions, while others may have fixed modes of operation that can only be adjusted manually, or cannot be adjusted at all. The objective of this synthesis is to document state DOT methods and criteria for defining critical findings for tunnel functional systems. Information to be gathered includes (but is not limited to): (1) Identification of state DOTs that have tunnels with functional systems as defined by NTIS section 650.505; (2) State DOT procedures for defining critical findings in functional systems (e.g., statewide criteria, criteria for individual tunnels, inspector recommended); (3) Basis for the critical findings criteria (e.g., original design, level of complexity, functional analysis, maintenance records, level of service, potential for imminent danger, AHJ involvement); (4) Location of critical findings criteria documentation (e.g., tunnel specific documentation, generic state DOT inspection manuals); and (5) Protocol for reporting critical findings to FHWA. Information will be collected through a literature review, a survey of state DOTs, and follow-up interviews with selected agencies for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.


  • English


  • Status: Active
  • Funding: $45000
  • Contract Numbers:

    Project 20-05, Topic 53-16

  • Sponsor Organizations:

    National Cooperative Highway Research Program (NCHRP) Synthesis

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Gause, Jo

  • Performing Organizations:

    Gannett Fleming, Incorporated

    209 Senate Avenue
    Camp Hill, Pennsylvania  United States  17011
  • Principal Investigators:

    Averso, Martha

  • Start Date: 20211014
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01771605
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 53-16
  • Files: TRB, RIP
  • Created Date: May 18 2021 7:54PM