Industry News

Updated US Tunnel Inspection Guidelines

Updated US Tunnel Inspection Guidelines

The National Tunnel Inspection Standards (NTIS) has a new guidance document, Compliance Review Manual, that gives guidance and direction to the FHWA Division Bridge Engineers in performing National Tunnel Inspection Program (NTIP) compliance reviews of State tunnel safety inspection programs.

The updates is being provided to States and other tunnel owners for informational purposes only. The document is guidance only and does not create any requirements other than those stipulated in statute or regulations.


In 2010, FHWA developed a new systematic, data-driven, risk-based oversight process for monitoring State compliance with the National Bridge Inspection Standards (NBIS). Based on the success of that process, FHWA has now developed a similar process for the recently implemented National Tunnel Inspection Standards (NTIS). 

This process utilizes 15 metrics, or measures, to define:
  1. the levels of compliance,
  2. items from the NTIS to be measured, and
  3. how those measurements affect the levels of compliance.
The metrics were developed over a 2-year period by a committee which consisted of FHWA Division, Resource Center, and Headquarters bridge and tunnel engineers. Refinements were made to the metrics based upon feedback received during development, including discussions based on pre-pilot evaluation of the metrics with a few States.

In 2017, the FHWA initiated a pilot program using the new process in eight additional States. The FHWA made further adjustments to the process and the metrics following these pilots, in preparation for nationwide implementation in June 2019.

Annual Review Schedule and 5-Year Review Cycle

According to the 23 U.S. Code § 144. National bridge and tunnel inventory and inspection standards the FHWA will annually review State compliance with the NTIS. A schedule is proposed for the different activities, and may need to be modified on a case-by-case basis when unique and unexpected extenuating circumstances arise.

As part of the 5-year review cycle the inspection program will examine the 5-year review history to identify trends in each metric area, to identify any gaps in the program or review process, and to develop a review strategy for the next 5 years.

The NTIS require tunnel owners to establish a program for the inspection of highway tunnels, to maintain a tunnel inventory, to report the inspection findings to FHWA, and to correct any critical findings found during these inspections.

Dealing with noncompliance deficiency

The FHWA Division Office will issue a signed report to the State detailing the issues of noncompliance for a metric determined to be noncompliant by December 31 of the review period. The report will list the regulatory code and title for each noncompliance deficiency, identify the deficiency, and specify that the deficiency has to be corrected, or a Plan of Corrective Action (PCA) submitted within 45 calendar days of notification. The State will have 45 days to either correct the issue of noncompliance or submit a PCA to FHWA as required. 

Read more: Link

Photo: Arild P. Sovik, Alaskan Way Replacement Tunnel in Seattle, June 2018

Author’s Posts


About us

Global news about road tunnels and technology in an operational perspective.

Tunntech AS

Markaneset 24a, 5251 Soreidgrend, Bergen, Norway

T: +(47) 950 88 793 • E:

© 2024 Tunntech. All Rights Reserved
Design & Developed by Tunntech AS