23 U.S.C. § 409 : US Code - Section 409: Discovery and admission as evidence of certain reports and surveys

      Notwithstanding any other provision of law, reports, surveys,
    schedules, lists, or data compiled or collected for the purpose of
    identifying, evaluating, or planning the safety enhancement of
    potential accident sites, hazardous roadway conditions, or railway-
    highway crossings, pursuant to sections 130, 144, and 148 of this
    title or for the purpose of developing any highway safety
    construction improvement project which may be implemented utilizing
    Federal-aid highway funds shall not be subject to discovery or
    admitted into evidence in a Federal or State court proceeding or
    considered for other purposes in any action for damages arising
    from any occurrence at a location mentioned or addressed in such
    reports, surveys, schedules, lists, or data.