AASHTO R 44-07 (2022)

Independent Assurance (IA)—Independent assurance is used in industry as an internal audit and review to support the accuracy of data and processes. In the highway industry, it is the outgrowth of a report from the Congressional House Committee on Oversights and Investigations (“Blatnik Committee”) that requires state departments of transportation (DOTs) to perform IA sampling and testing whenever federal funds are involved.

Purpose of IA—Independent assurance is an unbiased and independent assessment of all sampling, testing, and workmanship. This assessment includes evaluation of procedures and equipment used for the acceptance of highway materials and construction. 23 CFR Part 637 requires each state to have an IA Program. Independent assurance is used for verification of sampling procedures, testing procedures, and testing equipment.

Independent assurance is distinct from, and not intended as an acceptance process or for use in, verification of contractor sampling and testing results. Independent assurance is distinct from, and not intended for, quality control (QC) purposes. If IA results indicate a potential problem with quality, the results may be used to initiate additional testing.

Independent assurance sampling shall be done in such a manner as to minimize variability. In order to eliminate material and process variability, split samples should be used. Independent assurance samples may be taken independently of verification or acceptance samples, or may be a split of a verification or an acceptance sample.

Deficiencies in acceptance or QC processes that are identified through the IA program must be investigated and resolved. Otherwise, there is no purpose in identifying deficiencies.

This standard practice is applicable to design/build and warranty specifications as well as more conventional contracting methods. As a management principle, IA is a responsibility of the DOT that cannot be delegated to the contractor. (For example, contractors shall not hire their own IA inspectors or testers.)

Independent assurance is an essential tool that helps to ensure integrity within the quality assurance (QA) program. Independent assurance helps to prevent fraud and other criminal activities by evaluating sampling and testing procedures and competency. Independent assurance must be consistent throughout the agency. (It keeps the honest people honest by providing a “level playing field” for all contractors.)

Note—Many of the principles included herein have universal application. Although this standard practice for IA programs is developed specifically for construction materials, it can be applied to other processes. The principles inherent in the use of unbiased, consistent, and reliable information are applicable for any management effort. For example, construction workmanship is frequently inspected by either measurement or examination.