{
  "title": "Silver Bridge: dated events from design to the 1971 inspection rule",
  "description": "Dated events from the bridge's design to the 1971 inspection standards: one row per event, with start and end dates where a source gives a range, the precision of the date, and the days after the collapse counted two ways (calendar dates and day numbers). Where two sources give different dates, both are in the row and the qualifier says so; the date the standards took effect is reckoned as 30 days after publication, as the rule states.",
  "license": "CC BY 4.0",
  "license_url": "https://creativecommons.org/licenses/by/4.0/",
  "creator": "From the Surviving Record",
  "page": "https://fromthesurvivingrecord.com/failures/silver-bridge/",
  "derived_from": [
    "National Transportation Safety Board, Highway Accident Report NTSB-HAR-71-1 (adopted 16 December 1970), pages named in each label",
    "Federal-Aid Highway Act of 1968, Pub. L. 90-495, 82 Stat. 815, sec. 26 (82 Stat. 829)",
    "Federal Register vol. 36 no. 81 (27 April 1971), pp. 7851-7852, 23 CFR Part 25"
  ],
  "method": "Compiled by From the Surviving Record from the data listed",
  "data_credit": [
    "National Transportation Safety Board, Highway Accident Report NTSB-HAR-71-1, Collapse of U.S. 35 Highway Bridge, Point Pleasant, West Virginia (1970), retrieved 2026-11-01, public domain",
    "Federal-Aid Highway Act of 1968, Public Law 90-495, 82 Stat. 815 (1968), retrieved 2026-11-01, public domain",
    "National Bridge Inspection Standards, 23 CFR Part 25, Federal Register vol. 36, pp. 7851-7852 (1971), retrieved 2026-11-01, public domain"
  ]
}