Official websites use .gov
A .gov website belongs to an official government organization in the United States.
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.
The revision history file is a companion file to the National Transportation Dataset (NTD), Data Model, Version 2.1.2, summarizing the changes to the data model poster.
Public Domain.
