Mandating highway tunnel inspections
Mandating highway tunnel inspections Dec 2008
Legislation to set a minimum standard for inspecting highway tunnels is being advanced by the US Department of Transportation Federal Highway Administration (FHWA) in efforts to avert major failures and catastrophes that arise from lacks or non-existent inspection procedures.
Tunnel owners in the US are not mandated to inspect tunnels routinely. Inspections by agencies vary from daily to once every 10 years. This was roundly criticized by the National Transportation Safety Board (NTSB) when, after investigating the fatal July 2006 collapse of a suspended ceiling in the Central Artery Tunnel in Boston. The NTSB report stated that “had the Massachusetts Turnpike Authority conducted regular inspections of the tunnels in the area above

Central Artery Tunnel Collapse, July 2006

the suspended ceilings, the anchor creep that led to this accident would likely have been detected and action could have been taken that would have prevented this accident’’.
In response the Inspector General of the DOT, in his testimony before Congress in October 2007, highlighted the need for a tunnel inspection and reporting system to ensure the safety and security of the nation’s tunnels and stated the FHWA will seek legislative authority to establish a mandatory tunnel inspection program that would identify critical inspection elements and specify an appropriate inspection frequency. He added that the Administration ‘‘should move aggressively on this rulemaking and establish rigorous inspection standards as soon as possible.’’
To advance the process the FHWA is soliciting comments from industry, tunnel owners and operators towards creating a National Tunnel Inspection Standards (NTIS). The regulation would set minimum standards for inspection of all Federal-aid highway tunnels on public roads and cover inspection of structural, mechanical, electrical, hydraulic, and ventilation systems and would include the qualification and training of inspectors. Topics of discussion range from the definition of a ‘tunnel’ to the prevention and control of highway tunnel fires. Research conducted by the FHWA and others, related to tunnel design, construction, operation, rehabilitation, and inspection will also be reviewed. These include the Memorial Tunnel Fire Ventilation Test Program of 1993 and the Safety, Operations, and Emergency Response studies of Underground Transportation Systems in Europe.

Caldecott tunnel construction, Circa 1930s
Courtesy Caltrans

As well as setting the inspection procedures, the consultation process is also aimed at creating a national inventory of highway tunnels on that vast system of federal highways and public roads in the US. With no official inventory, the FHWA estimates that there are more than 300 highway tunnels in the nation and that these represent more than 100 linear miles of Interstate, State and local routes. The majority of these tunnels are said to range in age from 51 to 100 years with some, including the Caldecott Tunnel in California, constructed in the 1930’s and 1940’s. Statistics further show that the Lincoln Tunnel in New York carries approximately 120,000 vehicles per day, making it the busiest vehicular tunnel in the world. The Fort McHenry Tunnel in Maryland handles a daily traffic volume of more than 115,000 vehicles. These figures confirm the paramount importance of highway tunnels to the nation’s economic wellbeing and its defense.
The US Federal Highway and Federal Transit Administrations (FHWA and FTA) did develop guidelines for the inspection of tunnels in 2003. These were updated in 2005 and the FHWA subsequently developed Tunnel Management Software to help tunnel owners manage their tunnel inventory, but these have not been adopted uniformly. Those interested in contributing can download the guidelines for developing the legislation at the government website or from the Government Printing Office. Copies of the 2005 ‘Highway and Rail Transit Tunnel Inspection Manual’ are available at the Federal Highway Administration. Comments can be submitted and retrieved online through the Federal Docket Management System.
Comments must be received by February 17, 2009 with any received after that date considered to the extent practicable. Comments can also be submitted faxed to +1 (202) 493–2251 or posted to Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE, Washington, DC 20590–0001.


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