Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

News Archive

General Content

DOT Order 3910.1 Series Appendix A

Categorization of Employees for Testing

Testing Designated Positions (TDPs).

Safety/Security Critical - These are positions characterized as having critical safety or security...