A DOT physical drug test is a mandatory examination for commercial drivers to ensure they are physically and mentally fit to operate vehicles safely. This test includes a complete medical check-up and a drug test to find substances that might affect your ability to drive safely. A person who clears a DOT physical test is considered fit and assures that his driving ability is not defective. For detailed information on the DOT physical drug test and how to prepare, visit the NYUCC website.