The Federal Highway Administration recently observed the 50th anniversary of its National Bridge Inspection Standards (NBIS), the basis for the federal program that helps to protect nearly 620,000 structures across the country. The NBIS requires regular and thorough highway bridge inspections to detect potential structural problems early and ensure maintenance efforts are being carried out.
State departments of transportation inspect bridges, on average, once every 24 months and report the results to FHWA. If a bridge is rated as potentially unsafe, immediate actions are taken, including closure, prompt repairs, or load posting to restrict use by heavy vehicles. In addition to specialized training for bridge inspectors, the NBIS program also requires collection of structure condition data for inclusion in FHWA’s National Bridge Inventory, informing transportation officials’ funding priority decisions.
“For a half-century, NBIS standards have been at the core of federal infrastructure safety efforts,” says Acting FHWA Administrator Stephanie Pollack. “The data we collect under the program help keep bridges safe and identify areas where maintenance is needed before problems arise.” Even as the number of NBIS crossings has grown from 588,735 to 618,456 over the last 20 years, she adds, the program has ensured the structures are safe for the Americans who rely on them for travel and commerce.
FHWA officially adopted the NBIS regulations in 1971 after West Virginia’s Silver Bridge collapsed into the Ohio River because of a suspension chain crack. The 1967 tragedy, which cost the lives of 46 people, brought national attention to the issue of bridge condition safety and led to a systematic effort to ensure oversight at the national level. Since its inception, FHWA has worked to strengthen the program by updating inspector training requirements and replacing narrative bridge inspection summaries with specific assessment criteria to improve consistency.
The Federal Highway Administration’s National Bridge Inspection Standards program feeds data for the National Bridge Inventory, a transparent assessment of performance and integrity by structural material type and Interstate or other route classification.