Approved Products List (APL) The Approved Product List (APL) is updated every month. The link will take you to the current list. Changes to the APL are approved by the ADOT Product Evaluation Committees and are implemented by the first working day of the month following their action.  Please review FHWA memorandums and documents for product Category I, II, III, IV Certification requirements and approvals FHWA.  A copy of NCHRP Report 350 can be found at the Transportation Research Board web site. Documents are posted as they become available in PDF format, which requires Adobe Reader to view.