The "Drug and Alcohol Clearinghouse Public Safety Improvement Act of 2025" mandates that motor carriers operating vehicles weighing at least 10,000 pounds submit positive hair drug test results from pre-employment or random screenings to the Federal Motor Carrier Safety Administration's Drug and Alcohol Clearinghouse. This aims to enhance public safety by expanding the scope of reported drug test data. For these results to be valid, the hair drug tests must be administered using a covered device cleared under the Federal Food, Drug, and Cosmetic Act. Additionally, the testing laboratory must be accredited by the College of American Pathologists for forensic hair drug testing and incorporate Department of Health and Human Services guidelines. The Secretary of Transportation is directed to issue implementing regulations within one year, including updating the definition of "actual knowledge" to include these hair drug test results.