-Colorado Department of Transportation, (2018), “Colorado Tunnel Inventory and Inspection Manual”.
-Federal Highway Administration (FHWA) and Federal Transit Administration (FTA), (2005 Edition), “Highway -and Rail Transit Tunnel Inspection Manual”, (HRTTIM).
-Federal Highway Administration (FHWA) and Federal Transit Administration (FTA), (2005 Edition), “Highway and Rail Transit Tunnel Maintenance and Rehabilitation Manual”, (HRTTMRM).
-Federal Highway Administration, (2009), “Technical Manual for Design and Construction of Road Tunnels – Civil Elements”, Publication No. FHWA-NHI-10-034, Washington, DC.
-FHWA, (2015), “Tunnel Operations Maintenance”, Inspection and Evaluation (TOMIE) Manual.
-FHWA, (2015), “Specifications for the National Tunnel Inventory (SNTI)”.
-The Massachusetts Department of Transportation (MassDOT), (2018 Edition), “Tunnel Inspection Handbook”.
-Transportation Research Board, (2010), “Development of Guidelines for Rehabilitation of Existing Highway and Rail Transit Tunnels”, NCHRP Project 20-07/Task 276. Washington, DC.
-Transportation Research Board, (2011), “Best Practices for Roadway Tunnel Design”, Construction, Maintenance, Inspection, and Operations, Domestic Scan 09-05, NCHRP Project 20-68A.