The US Department of Transportation (DOT) regulation — 49 CFR Part 40 — defines the Substance Abuse Professional (SAP) as a person who evaluates employees who have violated a DOT drug and alcohol regulation and makes recommendations concerning education, treatment, follow-up testing, and aftercare.  In order to be a SAP, you need to have certain credentials, possess specific knowledge, receive training, and achieve a passing score on a DOT approved examination.