To help safeguard tunnel users and to ensure reliable levels of service, the FHWA developed the National Tunnel Inspection Standards (NTIS), the Tunnel Operations Maintenance Inspection and Evaluation (TOMIE) Manual, and the Specifications for National Tunnel . To help safeguard tunnel users and to ensure reliable levels of service, the FHWA developed the National Tunnel Inspection Standards (NTIS), the Tunnel Operations Maintenance Inspection and Evaluation (TOMIE) Manual, and the Specifications for National Tunnel . Tunnels represent a significant financial investment with challenging design, construction, and operational issues. Tunnels that are not adequately maintained usually require more costly and extensive repairs. To help safeguard tunnel users and to ensure reliable levels of service, the FHWA. unnel closures, increase public safety, and ensure adequate levels of service. It is commonly. Power supply and distribution in a tunnel Tunnels are home to a variety of applications that need to be supplied with power in a high-availability configuration. Phasing and sequencing is a. The work of Standardization) ha to be preparing International is a worldwide Standards federation is normally of standards governmental and non-governmental, with the International Electrotechnical Commission (IEC) on all matters of the in liaison represented interested on in a subject committee.