The purpose of this legislation, known as "Heidi's Law," is to enhance drug testing protocols in federal workplaces by specifically including methadone in the list of substances tested for. This aims to ensure that federal employees, particularly those in transportation roles, are subject to testing for methadone use, which is relevant for safety-sensitive positions. Key provisions of the law require the Secretary of Health and Human Services to update the Mandatory Guidelines for Federal Workplace Drug Testing Programs to include methadone within 90 days of the law's enactment.